US3302695A - Air conditioning means including controls therefor - Google Patents

Description

H. F. PAYNE Feb. 7, 1967 AIR CONDITIONING MEANS INCLUDING CONTROLS THEREFOR 6 Sheets-Sheet 1 Filed Dec. 2, 1964 l INVENTOR H urns Fosfe r Payne BY WXW ATTORNEYS Fig.2

Feb. 7, 1967 H. F. PAYNE 3,302,695

AIR CONDITIONING MEANS INCLUDING CONTROLS THEREFOR Filed D60. 2, 1964 6 Sheets-Sheet 2 INVENTOR Hams Fosrer Payne W%/% ATTORM X Feb. 7, H. F. PAYNE AIR CONDITIONING MEANS INCLUDING CONTROLS THEREFOR Filed Dec. 2, 1964 6 Sheets-Sheet 3 Fig.4

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H. F. PAYNE Feb. 7, 1967 AIR CONDITIONING MEANS INCLUDING CONTROLS THEREFOR 6 Sheets-Sheet 5 Filed Dec. 2, 1964 O T N E V m Harris Fosrer Payne @m M WZIZJV%& 7; ATTORNEYS MM N QNN ANN MNN mww mm W3 AIR CONDITIONING MEANS INCLUDING CONTROLS THEREFOR 6 Sheets-Sheet 6 Filed Dec. 2. 1964 INVENTOR Horns Foster Payne W m lfYs United States Patent 3,302,695 AIR CONDITIONING MEANS INCLUDING CONTROLS THEREFOR Harris Foster Payne, Arlington, Tex., assignor to Frigiking Company, Dallas, Tex., a division of Cummins Engine Company, Inc., a corporation of Indiana Filed Dec. 2, 1964, Ser. No. 415,293 11 Claims. (Cl. 165-27) This invention relates to control circuits and apparatus controlled thereby.

An object of the invention is to provide a new and improved control circuit for controlling operation of an apparatus which may be energized by alternating current of two different frequency ranges.

Another object is to provide a new and improved control circuit for an apparatus having drive means provided with two sets of windings which are adapted to be energized by alternating current of different frequency ranges, the control circuit selectively connecting one set of windings to an input circuit when the latter is connected to an alternating current source of one frequency range and connecting the other set of windings to the input circuit when the latter is connected to an alternating current source of another frequency range.

Still another object is to provide an air conditioning apparatus having a refrigerant system including a compressor for compressing a refrigerant gas, a condenser for cooling and liquefying the compressed refrigerant gas, an evaporator in which the cooled and liquefied gas evaporates and expands wherein the electric motors for driving the compressor, circulating air through the evaporator to cool the circulated air, and circulating air through the con-denser to cool the hot compressed gas are connectable to main electric conductors which may supply alternating current of two different frequency ranges, the motors each having one set of windings adapted to be energized by alternating current of one frequency range and another set of windings adapted to be energized by alternating current of another frequency range.

Still another object is to provide an air conditioning apparatus having a control circuit responsive to the frequency of the alternating current in the main conductors for selectively connecting the sets of motor windings across the main conductor as determined by the frequency of the alternating current.

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FIGURE 4 is a fragmentary end view of the apparatus with some parts removed, some parts broken away, and some parts in section;

FIGURE 5 is a fragmentary top view of the apparatus with a portion of the top broken away;

FIGURE 6 is a schematic diagram of one portion of the control circuit of the apparatus;

FIGURE 7 is a continuation of FIGURE 6 and shows another portion of the control circuit; and,

FIGURE 8 is a continuation of FIGURE 7 and shows a third portion of the control circuit.

Referring now to the drawings, the air. conditioning apparatus 20 includes a housing 21 having a bottom 22, a top 23, front and rear walls 24 and 25, respectively, and end walls 26 and 27 which are rigidly secured to one another and to a rectangular housing frame 28 in any suitable manner, as by bolts or screws. The bottom has an upstanding peripheral aflnge 29 within which the four corner columns 30a-d of the frame are received. The end walls are provided with vertical side flanges 31 which abut the sides of adjacent corner columns. The side walls extend between the end flanges 31 of the two end walls and their end portions also abut the sides of the columns.

The top or cover 23 of the housing has a continuous peripheral flange 34 which telescopes over the top portion of the support frame 28 and which may also be secured to the frame by screws or bolts.

. The front wall 24 is substantially L-shaped with its top edge disposed below or butting the bottom edge of the flange 34 of the top, its bottom edge abutting the top edge of the front longitudinal portion of the bottom flange and the front sides of the corner columns 30b and 300. A grill assembly is mounted in the rectangular opening provided by the L-shaped front wall 24. The grill assembly includes a rectangular grill frame A further object is to provide an air conditioning apparatus having means for circulating air therethrough, a refrigerant system for cooling the circulated air, a heating means for heating the circulated air and control means for selectively placing either the refrigerant system or the heating means in operation.

An important object is to provide an air conditioning apparatus for heating or cooling air in a closed compartment, such as a room for a building structure, and for introducing fresh air into the compartment.

Another object is to provide an air conditioning apparatus of the type described having a control circuit for selectively causing the apparatus to heat or cool the air in the compartment or to introduce fresh air thereinto.

Additional objects and advantages of the invention will be readily apparent from the reading of the following description of the device constructed in accordance with the invention, and reference to the accompanynig drawings thereof, wherein:

FIGURE 1 is a perspective view of the air conditioning apparatus embodying the invention showing the front side thereof;

FIGURE 2 is a perspective View of the apparatus showing the rear side thereof;

FIGURE 3 is a perspective exploded view, with some parts broken away, of the apparatus;

41 having top and bottom horizontal members 42 and 43, and vertical end members 43 and 44 which provide a continuous inwardly extending flange 45 which extends into such opening. The outer flange of the grill is disposed in a vertical plane and abuts the outer surface of'the annular column 30, a dependent flange of the front horizontal top frame member 46, a vertical dependent flange 47 of a horizontal partition 48 and the front flange 50 of a baflle 51. The grill frame 41 has an upper horizontal divider 52 and a lower horizontal divider member 53 which divide the grill into top, middle and bottom horizontal passages 55, 56 and 57, the top and middle pas sages being of greater height than the bottom passage. Suitable vertical brace members 59 are positioned between the divider members and the frame and are rigidly secured thereto in any suitable manner, as by welding or the like.

The grill assembly also includes a grill 60 having a plurality of spaced horizontal wires 61 which are rigidly secured by welding or the like to the vertical wires 62 which are provided at their top and bottom ends with eyes 64. The eyes 64 extend perpendicularly from the vertical wires and are securable to the grill frame by means of bolts 65 which may extend through the eyes into the horizontal flanges of the grill frame.

The partition 48 divides the housing into a top chamber 66 and a bottom chamber 68. The grill assembly permits flow of air into the top chamber at the front side of the housing for passage through a filter 70, an evaporator 71 and a heater assembly 72 and then to the exterior of the housing through a blower 75 mounted in the top chamber whose outlet duct 76 extends through a suitable aperture 77 of the end wall 27. The end wall may be provided with a suitable internal bracket or frame 78 into which the outer end of the outlet duct of the blower 75 may extend.

The evaporator has end plates 79 and 80 whose flanges 81 and 82 abut and are secured to the flanges 83 and 84 of the vertical brackets 51 and 86. The filter 70 extends between the baflies 51 and 86 and between the top and bottom channel members 87 and 88 which are secured to the top 23 and the horizontal partition.

The baflle 51, the end wall 27, the baffle 57, the end wall 26, the top 23, the horizontal partition 48, the bafile 86 and the channel members 87 and 88 form a passage to insure that all air being moved through the grill assembly 40 by the blower 75 moves through the filter, the evaporator and the heater assembly 72.

A drain pan 90 extends rearwardly of the filter below the evaporator to receive any condensate from the evaporator. Two or more condensate drain tubes 91 which open to the drain pan extend downwardly from the drain pan and outwardly through an outlet duct 92. An insulating material 93, such as asbestos, rockwool or the like is disposed between the drain pan and the partition.

The passages 55, 56 and 57 of the grill frame are closable by doors 95, 96 and 97, respectively. The door 95 is pivotally secured by the hinge 99 to the horizontal divider 52, the door 96 is pivotally secured by a hinge 100 to the horizontal divider 53 and the door 97 is pivotal- 1y secured by the hinge 101 to the bottom horizontal member 43 of the grill frame and also to the horizontal partition 48. The bottom door 97 when in its lower position illustrated in FIGURE 4 closes an aperture 103 in the partition 48 which provides communication between the chambers 66 and 68. The doors are movable from their horizontal positions illustrated in FIGURE 4 wherein the bottom door 87 closes the passage 90 and wherein the passages 55, 56 and 57 of the grill frame are open by an operating mechanism which includes two operator bars 104 at opposite ends of the doors. Each of the operator bars has inwardly extending pins 105 and 106 which extend slidably through the slots 107 and 108 of the side flanges 109 and 110 at opposite ends of the top and middle doors, respectively. The bottom door 97 has vertical arms 114 at its sides pivotally connected by pins 115 to the operator bars. The relatively thin operator bars extend downwardly through the aperture 103 at the opposite ends thereof. The upper ends of the operator bars are pivotally connected by pins 119 to brackets 210 pivotally secured to the top member 42 of the grill frame by hinges 121. A drive link 122 is connected at its upper end by means of the pin 115 to one of the operator bars. The drive link is threaded in the bore of a rotatable drive shaft 124 of an electric drive unit 124a, such as is commercially available under the name Actuator from Air Research Corporation Company. The drive shaft 124 is pivotable at its lower end and is rotated when the drive unit 124a is connected to a source of electric current. When the drive shaft is rotated in one direction relative to the drive link, the drive link is moved outwardly and upwardly and when the drive shaft is rotated in the opposite direction the drive link is moved inwardly and downwardly. It will be apparent that as the drive link 122 is moved upwardly, the operator bars are moved upwardly until all three doors are in their vertical positions, the bottom door 97 then abutting the inner end of the bottom horizontal divider 53 to close the bottom passage, the door 96 abutting the inner edge of the upper divider 52 to close the middle passage, and the top door 95 abutting the inner end of the top horizontal frame member 42 to close the top passage. At this time the aperture 103 of the horizontal partition is open.

It will be apparent that when the doors are in their upper positions and the blower 75 is in operation, air flows upwardly from the bottom chamber 68 through the aperture 90 in the partition 48 and then through the filter, the evaporator and the heating coils before moving to the exterior of the housing through the outlet duct of the blower.

The heating assembly 72 which includes a plurality of heating elements 125, which may be Calrods or the like,

.4 is mounted by means of suitable brackets 127 and 128 inwardly of the evaporator so that all air being moved by the blower through the evaporator also passes through the heating assembly. The blower 75 is driven by a suitable electric motor 130 mounted by means of a bracket 131 on the horizontal partition 48. The housing of the blower itself is, of course, secure-d to the partition 48 by any suitable means.

The rear Wall 25 is preferably formed of a top section 25a and a side section 25b to form with the bottom and frame of the housing a rectangular aperture or passage through which air may be drawn into the bottom chamber 68 past the condenser 141 mounted in the bottom chamber. The condenser 141 has the usual end or mounting plates 142 and 143 whose vertical outer flanges 144 and 145, respectively, are rigidly secured to a retainer strip 146 and to the side wall section 25b by any suitable means as by screws or bolts. Suitable spacer strips 148 and 149 are interposed between the side section 25b and a bottom retainer strip 150. The retainer strips 146 and 150 may be rigidly secured as by welding or the like to the corner post 30d of the housing frame and the flange 29 of the bottom 22. The two sections of the rear wall are secured to the housing frame by screws or the like.

Air is movable inwardly into the bottom chamber 68 through the aperture 140 and the condenser 141 by a pair of blowers 154 and 155 which are driven by the electric motors 156 and 157, respectively. The outlet ducts 159 of each of the blowers is connected and opens to the air outlet duct 92 so that the air warmed in its movement past the condenser 141 is moved to the air outlet duct above the opening or passage 141 of the rear wall of the housmg.

The compressor 160 for compressing the refrigerant gas, which is then transmitted to the condenser 141 by suitable conduits for cooling and condensation, is mounted in the bottom chamber 68 and is driven by an electric motor 161 also mounted in the bottom chamber. The blowers and their motors and the compressor and its motor are rigidly mounted by suitable brackets, bolts and the like to the bottom 22 of the housing. The cooled and condensed refrigerant gas from the condenser is conducted by suit able conduits to the tubes of the evaporator '71 and from the evaporator back to the compressor for compression thereby. It will be apparent that the compressor 160, the condenser 141 and the evaporator 71 constitute a refrigerant system for cooling air which is moved past the tubes of the evaporator 41 and, accordingly, such system will not be described in greater detail. If desired, the refrigerant system may also include a reservoir or tank in which the cooled and condensed refrigerant gas, after passing through the compressor, may be stored before its passage to the evaporator.

Electric current is transmitted to the motors 130, 157, 156, 161 and to the heating elements from the main conductors 201, 202, 203 and 204 by means of a suitable outlet plug 205 which is mounted on the end wall 26. It will be apparent that various electric conductors extend from such plug to the motors and to the various components of the electrical control system which are, of course, mounted in appropriate locations within the housing. The conductors connecting such components to each other and to the plug 205 extend through suitable aperture or apertures in the horizontal partition 48. The control assembly 210 for controlling operation of the air conditioning apparatus is connectable to the various electrical components of the apparatus by cable 211 and the plug 212 mounted on the wall 27.

It will now be apparent that when the apparatus is to be employed to cool the air within a closed space for example, a room or compartment of a building structure, the housing is secured to and adjacent an outer wall of the building structure provided with an aperture with the grill of the front wall in alignment and communication with such aperture soiair may be drawn from such room through the grill assembly 40 into the upper chamber 66 of the housing. The outlet duct 76 of the evaporator blower 75 is connected by a suitable duct to such compartment preferably at a location spaced from and lower than the location at which air is drawn from the compartment into the upper chamber through the grill assembly 40. Air from the compartment may then be circulated from the compartment through the upper chamber 66 and then back to the compartment. If it is desired that the air be cooled, the refrigerant system is set in operation and the refrigerant gas evaporating and expanding in the tubes of the evaporator absorbs heat from the air being circulated therepast. The condenser blower motors 156 and 157 are then in operation moving the air inwardly into the bottom chamber through thecondenser 141 from the atmosphere, such air absorbing heat from the refrigerant gas as it moves through the tubes of the condenser, and then blowing the heated air from the bottom chamber to the atmosphere through the air outlet duct 92.

If it is desired to merely circulate fresh air through such compartment, the drive unit 124a is energized to move the doors 95, 96 and 97 to their upper positions wherein the passages of the grill assembly are closed and the operation of the blower 75 then causes fresh air from the atmosphere to be drawn into the bottom chamber 68 through the passage 140 of the housing and the heat exchanger and then upwardly through the now opened aperture 103 of the partition into the top chamber 66, through the filter 70 and past the evaporator and the heater assembly into the room.

If it is desired merely to recirculate and heat the air 'in such closed chamber, doors 95, 96 and 97 are moved to their closed position and the air is circulated therethrough such closed chamber and the upper chamber of the housing by the operation of the blower 75 and while the heating assembly 72 is energized.

Each of the motors for driving the compressor, the evaporator blower and the condenser blowers is a three phase induction motor having one set of stator windings A, B and C which are connected in Y and are energizable by a three phase alternating current of 47-63 cycles per second frequency and a second set of windings A, B and C which are energizable by a three phase alternating current of between 380 and 420 cycles per second frequency. The 60 cycle stator windings are wound to provide a two pole motor while the 400 cycle frequency windings are wound to provide a twelve pole motor in order that the speed of rotation of the motors be substantially the same whether the main conductors are connected to a three phase, source of 47-63 cycle frequency or of 380-420 cycle frequency. The 60 cycle frequency windings A, B and C of the compressor motor 161 and the condenser blower motors 156 and 157 are connectable across the main conductors 201204 by a contactor 210 when its winding 211 is energized. The movable contacts 214, 215 and 216 connect the terminals 217, 218 and 219 of a terminal board 220 to the main conductors 201, 202 and 203, respectively, when the winding 211 of the contactor is energized. The contact 214 and the conductors 221, 222 and 223 connect the terminal 217 to the main conductor 201. The contact 215 and the conductors 225, 226 and 227 connect the terminal 218 to the main conductor 202. The contact 216 and the conductors 228 connect the terminal 219 to the main conductor 203. The main common conductor 204 is connected to the common terminal 231 of the terminal board by the conductors 232, 233 and 234.

The common terminal 231 of the terminal board is connected to the common connection of the stator windings A, B and C of the compressor motor 161 by the conductor 235 while the other sides of the stator windings A, B and C are connected to the terminals 217, 218 and 219 by the conductors 236, 237 and 238, respectively. The conductors 236, 237 and 238 may have overload 6 fuses connected therein. It will be apparent therefore that when the winding 211 of the contactor 210 is energized, the 60 cycle frequency windings A, B and C of the compressor motor are connected across the main conductors 201, 202, 203 and 204.

The common connection of the 60 cycle frequency stator windings A, B and C of the condenser blower motor 156 are connected to the terminals 217, 218 and 219 by the conductors 241, 242 and 243 while their common connection is connected to the common terminal 231 by the conductor 244, so that the 60 cycle stator winding of the motor 156 are also connected across the main conductors when the winding 211 of the contactor 210 is energized.

The stator windings A, B and C of the other condenser blower motor 157 are similarly connected to the common terminals 217, 218 and 219 by the conductors 246, 247 and 248 while their common connection is connected to the common terminal 231 by the conductors 249 and 244. It will thus be apparent that whenever the contactor 210 is moved to closed position the 60 cycle stator windings of the compressor motor and the condenser blower motors are connected across the main conductors and these motors are placed in operation. As will be explained below, the winding 211 of the conductor 10 is energized only when the frequency of the three phase alternating current across the main conductors is of 60 cycle frequency. When the winding 250 of another contactor 251. is energized, the movable contacts 253, 254 and 255 of the contactor 251 are in their closed positions and connect the terminals 257, 258 and 259 of the terminal board 220 to the conductors 229, 227 and 223, respectively, and thus to the main conductors 203, 202 and 201, respectively. The contact 253 and the conductors 261 and 262 connect the terminal 257 to the conductor 229. The

contact 254 and the conductors 263 and 264 connect the terminal 258 to the conductor 224 and the contact 255 and the conductors 265 and 266 connect the terminal 259 to the conductor 223.

The 400 cycle frequency stator windings A, B and C of the compressor motor 161 are connected to the terminals 257, 258 and 259 by the conductors 271 and 272, 273 and 274, and 275 and 276 while their common connection is connected to the terminal 231 by the conductor 277. It will thus be apparent that when the contacts of the contactor 251 are in their closed positions, the 400 cycle frequency stator windings are connected across the main conductors 201-204. The conductors 271, 273 and 275 may have overload fuses, not shown, connected therein.

In order to improve the power factor of the apparatus when the compressor motor is energized with three phase alternating current of 400 cycle frequency, the capacitors 281, 282 and 283 are connected across the windings A, B' and C, the common connection of the capacitors 281 and 283 being connected by the conductor 285 to the winding A by the conductors 285 and 271, the common connection of the capacitors 282 and 283 being connected to the winding B by the conductors 286 and 273, and the common connection of the capacitors 281 and 282 being connected by the conductors 287 and 273 to the stator winding C. It will thus be apparent that whenever the 400 cycle stator windings of the compressor motor are connected across the main conductors, the capacitors 281, 282 and 283 are also connected thereacross.

The 400 cycle stator windings A, B and C of the condenser blower motor 165 are also connectable by the contactor 251 across the main conductors 201-204, the

terminal 257 being connected to one end of the stator I 7 connected to the terminal 231 by the conductors 298 and 299.

The stator windings A, B and C of the other condenser blower 157 also connected across the terminals 275, 258, 259, and 230 since the winding A is connected to the conductor 291, the winding B is connected to the conductor 293, the winding C is connected to the conductor 296 and the common connection of these windings is connected to the conductor 298.

The delta connected capacitors 301, 302 and 303 are connected across the 400 cycle stator windings of the two condenser blower motors, the common connection of the capacitors 301 and 303 being connectors to the conductor 291 by the conductor 305, the common connection of the capacitors 301 and 302 being connected to the conductor 293 by the conductor 306 and the common connection of the capacitors 302 and 303 being connected to the conductor 296 by the conductor 307.

The 60 cycle frequency stator windings A, B, and C of the evaporator blower motor 131 are connected across the main conductors 201-204 when the contacts 311, 312 and 313 of the contactor 314 are moved to their closed position when the winding 315 of the contactor is energized. When the winding 315 is energized, the stator winding A is connected to the conductor 223 by the conductor 317, the contact 311 and the conductor 318, the winding B is connected to the conductor 297 by the conductor 319, the contact 312 and the conductor 320, the winding C is connected to the conductor 229 by the conductor 322, the contact 313 and the conductor 323, and the common connection of the windings A, B, and C is connected to the conductor 233 by the conductor 324.

The 400 cycle stator windings A, B and C of the evaporatod blower motor 131 are connectable across the main conductors 201-204 by the contacts 326, 327 and 328 of the contactor 330 when its winding 331 is energized. When the contactor winding 331 is energized, the stator winding A is connected to the conductor 229 by the conductor 334, the contact 326 and the conductor 335, the winding B is connected to the conductor 227 by the conductor 337, the contact 327 and the conductor 338, the stator winding C is connected to the conductor 223 by the conductor 339, the contact 328 and the conductor 340, and the common connection of these windings is connected to the conductor 233 by the conductor 341.

The set of heater elements 125a, 125b and 125a are connected in delta across the main conductors 101, 102 and 103 when the winding 350 of the contactor 351 is energized and moves its contacts 352, 353 and 354 to their closed positions. When the winding 350 is energized, the common connection of the heating elements 152a and 1250 is connected to the conductor 223 by the conductor 356, the contact 352 and the conductor 357, the common connection of the heating elements 125a and 125b is connected to the conductor 227 by the conductor 358, the contact 353 and the conductor 359, and the common connection of the heating elements 125b and 125:: is connected to the conductor 229 by the conductor 360, the contact 354 and the conductor 361. The other set of heating elements 125d, 125a and 125] is similarly connected across the conductors 201 and 202 by the contactor 363 when its winding 364 is energized and moves the contacts 366, 367 and 368 to their closed positions. When the winding 364 is energized, the common connection of the heating elements 125d and 125 is connected to the conductor 123 by the conductor 368, the contact 366, and the conductor 369, the common connection of the heating elements 125d and 125a is connected to the conductor 227 by the conductor 371, the contact 367 and the conductor 372, and the common connection of the heating elements 125e and 125 is connected to the conductor 229 by the conductor 374, the contact 368 and the conductor 375. If desired, either the set of heaters 125a, 1251) and 1250 may be energized or if an increased rate of heating is desired, the other set of heaters d, 125e and 125 may also be energized. Since the heating elements are resistances with no appreciable inductance, they may be energized either by 400 cycle or 60 cycle frequency alternating current without decreasing the power factor of the apparatus.

The energization of the windings 211, 250, 315 and 331 of the contactors 210, 251, 314 and 330 is controlled by a frequency selector circuit 380 and two relays 381 and 382 whose operation is controlled by the frequency selector circuit. The winding 384 of the relay 381 is energized by the frequency selector circuit 380 when an alternating current within a frequency range of between 47 and 63 cycles per second is impressed across the main conductors 202 and 204 and the winding 385 of the relay 382 is energized by the frequency selector circuit when an alternating current within afrequency range of 380 to 420 cycles per second is impressed across the main conductors 202 and 204. The frequency selector circuit has a first resonant or frequency responsive circuit which includes an inductance 390 and a capacitor 391 which are connected in series with a heating element 392 across the main conductors 202 and 204 by means of the conductors 394, 396, 397 and 234, When an alternating current within the range of 47 to 63 cycles per second is applied across this resonant circuit current flows through the heating element 392 causing it to heat the bimetallic contact 401 which closes. The contact 401 when in its closed position connects the relay winding 384 across the output conductors 402 and 403 of a rectifier 404 by means of the conductors 405, 406 and 407.

The frequency selector circuit also includes a second resonant or frequency responsive circuit which includes an inductance 410 and a capacitor 411 which are connected in series with a heating element 412 across the main conductors 202 and 204 by means of the conductors 394, 396, 397 and 234. When the frequency of the alternating current applied across this second resonant circuit is within the range of 380 to 420 cycles per second, current flows through the heating element and a bimetallic element 415 is heated thereby to cause it to move to its closed position and connect the relay winding 385 across the output conductors 402 and 403 of the rectifier 404 by means of the conductors 405, 409, 410 and 407.

When the relay winding 384 is energized its lower contact 411 is moved upwardly and connects one side of the winding 211 of the compressor motor contactor 210 to the negative conductor 402 of the output circuit of the rectifier to the positive side or conductor 402 through the conductors 413 and 414, the lower contact 415 of the relay 382 which is now in its lower position, the conductors 416 and 417, the emitter collector circuit of a control transistor 418 of a temperature control circuit 420, the conductor 421, the stationary contact 422, the movable contact 423 of a rotatable wafer switch W1 when it is rotated to the position wherein the radially outwardly protruding portion 424 of the movable contact engages the stationary contact 422, the stationary contact 425 which is always in engagement with the movable contact 423 and the conductors 426 and 427. The other side of the contactor winding 211 is connected to the negative output conductor 403 of the rectifier by a conductor 430, a temperature sensitive switch 431 which senses the temperature in the compressor crankcase and is provided to prevent operation of the compressor motor when liquid refrigerant is present in the compressor crankcase, the switch closing when the compressor crankcase temperature reaches 118 degrees Fahrenheit, a conductor 432, a compressor overload switch 434 which senses the temperature of the compressor motor and opens if the latter overheats, the conductor 435, a switch 436 which is sensitive to the temperature of the condenser blower motor 157 and opens if. the latter overheats, the conductor 437, a pressure responsive switch 438 responsive to the discharge and suction pressures of the compressor which opens it the suction pressure falls below a predetermined low level, for example, p.s.i.g., and closes when the suction pressure increases to 50 p.s.i.g. and which also opens if the discharge pressure of the compressor increases to a point above a safe value, for example, 435 p.s.i.g., the conductor 439, a switch 440 which is sensitive to the temperature of the other condenser blower motor 156 and opens when the latter overheats, the conductors 442, 443 and 444, the switch 445 which is responsive to the temperature of the evaporator blower motor 131 and which opens when the evaporator motor overheats, and the conductor 447.

It will be apparent that if the movable contact 423 is in the position wherein it engages stationary contact 422, and the emitter-collector circuit of the control transistor 418 is conductive, the winding 211 of the contactor 210 will be connected across the conductors 402 and 403 and consequently the 60 cycle stator windings A, B and C of the compressor motor and of the condenser blower motors 156 and 175 will be connected across the main conductors and will operate as long as the switches 431, 434, 436, 440 and 445 remain in closed condition. Should the suction or discharge pressures of the refrigerant gas at the inlet and outlet of the compressor fall below or above predetermined value or should any one of the compressor or blower motors becomeoverloaded and overheat, the contactor winding 211 will be disconnected from across the output conductors 402 and 403 of the rectifier thus causing the contactor 210 to move to its open condition and stop operation of the compressor motor and of the condenser blower motors.

When the relay winding 3 84 is energized one side of the winding 315 of the contactor 314, which controls connection of the 60 cycle windings A, B and C of the blower motor 131 to the main conductors 201204, is connected to the positive output conductor 402 of the rectifier 404 through the conductor 451, the upper contact 452 of the relay 482 which is now in its lower position, the conductor 454, the upper contact 455 of the relay 382 which is now in its upper position, the conductor 456, the stationary contact 458 of a wafer switch W2, the movable contact 459 with which the stationary contact 458 is always engageable, one of the stationary contacts 461, 462 or 463 when the wafer switch W2 is rotated to any one of three positions wherein its radially outwardly protruding portion 465 of its movable contact 459 engages any one of the stationary contacts 461, 462 and 463, the conductor 427 which is connected to these stationary contacts by the conductors 468, 469 and 470, respectively. The other side of the contactor winding 315 is connected to the negative output conductor 403 of the rectifier by the conductors 471, 443 and 444, the switch 445 and the conductor 447. It will now be apparent that when a 60 cycle alternating current is applied across the main conductors 201-204, the evaporator blower motor 131 will be in operation as long as the overload switch 445 remains closed if the wafer switch W2 is in any one of its three positions wherein the movable contact 459 is in engagement with one of the stationary contacts 461, 462, or 463.

When a 400 cycle alternating current is impressed across the main conductors 201204, the winding 250 of the contactor 251 is connected to the positive output conductor 402 of the rectifier by the conductor 481, the lower contact 411 of the relay 381 which is now in its lower position, the conductor 482, the lower contact 415 of the relay 382 which is now in its upper position, the conductor 417, the emitter collector circuit of the control transistor 418, the conductor 421 and the stationary contact 422 of the rotatable wafer switch W1 when its movable contact 423 is in the position wherein its radially outwardly extending portion 424 is in engagement with the stationary contact 422, the stationary contact 425 and the conductors 426 and 427. The other side of the contactor winding 250 is connected to the negative output conductor 403 of 10 the rectifier through the switches 431, 434, 436, 438, 440 and 445 in the same manner as the contactor winding 211 so that the contactor winding 250 like the contactor winding 211 will be deenergized whenever the pressure conditions of the refrigerant gas on opposite sides of the compressor inlet and outlet are out of predetermined ranges or an overload condition ocurs in any one of the blower and compressor motors.

When the contactor winding 250 is energized, of course, the condenser blower motors 156 and 157 and the compressor motor 161 are connected across the main conductors 201204 in the manner described above.

When an alternating current of 400 cycle frequency is impressed across the main conductors 201204, the winding 331 of the contactor 330 is connected to the positive output conductor 402 of the rectifier 404 by means of the conductor 491, the upper contact 452 of the relay 381 which is now in its upper position, the conductor 492, the upper contact 455 of the relay 382 which is now in its lower position, the conductors 494 and 456, the contacts 458 and 459 of the wafer switch W2, one of the contacts 461, 462 or 463 of the wafer switch W2 when its movable contact 459 is in engagement with one of them and the conductor 427. The opposite side of the contactor winding 331 is connected to the negative output conductor 403 by the conductors 496, 443 and 444, the evaporator blower motor overload switch 444, and the conductor 447.

The cooling control circuit 420 is responsive to the temperature of the air being moved inwardly into the upper passage 66 through the grill, which is sensed by a thermistor 500 positioned preferably within the upper chamber 66 upstream of the filter 70 in any suitable location. The thermistor is connected between the conductors 421 and 502, which have the capacitor 503 connected thereacross, by the conductor 504, the conductor 506, a variable resistance 507, diode 508, a variable resistance 509 and a resistance 510. When the wafer switch W1 is moved to the position wherein its movable contact 423 engages its stationary contact 422, the conductor 421 is connected to the positive output conductor 402 of the rectifier and thus has positive or plus 28 volts applied to it and simultaneously the other movable contact 510 of the wafer switch W1 is in position wherein its radially outwardly extending end portion 511 is in engagement with the stationary contact 512 which is connected to the conductor 502. The conductor is thus connected to the output conductor 514 of the voltage regulator 515 by means of the stationary contact 517 which is always in contact with the movable contact 510. The voltage regulator 515 maintains a constant negative voltage, for example, 12 volts, on the conductor 514.

It will thus be seen that the thermistor is connectable in series with the variable resistance 507, the diode 508, the variable resistance 509 and the resistance 510 across the conductors 421 and 502 and constitutes one element of a voltage divider bridge formed by these elements. The common connection of the diode 508 and the resistance 509 is connected to the base of a transistor 520 whose emitter is connected to the conductor 502 by the resistance 521. When the temperature of the thermistor is below a certain value and its resistance is high, the emitter-collector circuit of the transistor 520 is con" ductive, its emitter being connected to the conductor 502 by the resistance 521 and its collector to the conductor 421 by the resistance 524. When the temperature of the thermistor rises and its resistance decreases below a certain value, the emitter-collector circuit of the emitter becomes less conductive or nonconductive. The output of the transistor 520 is applied the base of a transistor 526, which is connected to the common connection of the resistance 524 and the collector of the transistor 520. The base of the transistor 526 is also connected to the common connection of the resistances 527 and 524 connected in series across the conductors 421 and 502.

The emitter of the transistor 528 is connected to the conductor 502 by the resistances 529 and 521 and its collector is connected to the conductor 521 by the relay winding 531. A diode 533 is connected between the common connection of the collector of the transistor 521 and the conductor 421 to prevent any inductive surge in the emitter-collector circuit of the transistor 526. As the conductivity of the emitter-collector circuit of the transistor 520 decreases, the conductivity of the emitter-collector circuit of the transistor increases. The relay winding 531, when a suflicient current flows therethrough and through the emitter-collector circuit of the transistor 526, moves its contact 535 to connect the resistances of which divide the resistances 536 and 537a in series across the conductors 421 and 537 to render the emitter-collector circuit of the transistor 418 conductive since its base is connected to the common connection of the resistances 536 and 537. The conductor 537 is connected to the negative output conductor 403. A diode 538 is connected across the base-collector circuit of the transistor 41% and the resistance 536.

The resistances 509 and 507 may be adjusted to vary the temperature of the inflowing air at which the transistor 418 is rendered conductive. Since the windings 211 and 250 of the contactors 210 and 251 which control the operation of the compressor motor and the condenser blower motors are thus controlled by the conductivity of the transistor 418 of the control circuit 420, which in turn is controlled by the thermistor 500 which senses the temperature of the air being drawn into the upper chamber 66, the thermistor 500 controls the operation of the refrigerant system of the apparatus and causes the refrigerant system to function each time the temperature of the air being drawn into the upper chamber through the grill assembly rises above a predetermined temperature and to stop operation of the refrigerant system when this temperature drops below the predetermined value.

The evaporator blower motor 131, however, operates whenever the wafer switch W2 is in any one of the three positions wherein its movable contact 459 engages any one of the contacts 461, 462 and 463 and, as will be explained below, whenever either the compressor motor or the heater assembly is connected across the main conductors 201204.

The winding 350 of the contactor 351 which controls the connection of the set of heating elements 125a, 12517 and 125a across the main conductors 201, 202 and 203 is connected to one side of the positive output conductor 403 by the conductor 545, the stationary and movable contacts 546 and 547 of a relay 548 when its winding 549 is energized, and the conductors 551, 552 and 553. The other side of the contactor winding 350 is connectable to the negative output terminal 403 by the conductor 555, a temperature sensitive switch 557 which is located in the upper chamber adjacent the heating element 125 and which opens when the temperature at such location exceeds a predetermined value, the conductors 558, 443, 444, the evaporator blower overload motor switch 445, and the conductor 447.

One side of the winding 364 of the contactor 363, which controls the connection of the second set of heating elements 125d, 125:: and 125f across the main conductors 201, 202 and 203, is connectable to the positive output conductor 403 by the conductor 561, the stationary and movable contacts 562 and 563 of a relay 564 when its winding 565 is energized, and the conductors 552 and 553. Its other side is connectable to the negative output conductor 403 through the conductors 567, 555, the switch 557, the conductors 558, 443 and 444, the evaporator blower overload switch 445 and the conductor 447.

The energization of the relay windings 549 and 565 is controlled by a control circuit 570 which includes a thermistor 571 which is also positioned in the chamber 66 upstream of the filter 70 to sense the temperature of the air being drawn into the upper chamber 66 through the grill assembly of the housing and which is connected by the conductors 573 and 574 in series with a variable resistance 575, a diode 576, a variable resistance 577 and a resistance 578 across the conductors 581 and 582. A capacitor 583 is also connected across the conductors 581 and 582. The conductor 581 is connected to the output conductor 514 of the voltage regulator 515 when the movable contact 510 of the wafer switch W1 is rotated to such position that its radially outwardly extending portion 511 engages the stationary contact 586 to which the conductor 581 is connected since the contact 517 of the wafer switch W1 is always in engagement with the movable contact 510. When the wafer switch W1 is in the position wherein its movable contact 510 engages its stationary contact 586, its other movable contact 423 engages its stationary contact 588 which is connected to the conductor 582 and thus connects the conductor 582 to the positive output conductor 402 of the rectifier through the contact 425 and the conductors 426 and 427. When the temperature of the inflowing air drops below a predetermined value and the resistance of the thermistor 571 increases to a predetermined value, the conductivity of the emitter-collector circuit of a transistor 590 increases since its base is connected to the common connection of the resistance 577 and the diode 576, its collector is connected to the conductor 581 by the conductor 591 and its emitter is connected to the conductor 582 through the diode 593 and the serially connected resistance 594 and 595. The output of the transistor 590 controls the conductivity of the emitter-collector circuit of the control transistor 598 whose base is connected to the common connection of the emitter of the transistor 590 and the diode 593. The collector of the control transistor 598 is connected to the conductor 581 by the resistance 601 and its emitter is connected to the conductor 582 by a differential trim resistance 602, whose adjustable contact 603 is connected to the emitter, and the relay windings 605 and 606 which are connected to opposite ends of the trim resistance. Diodes 609 and 610 are connected across the relay windings 605 and 606. It will be apparent that the relative current flow through the two relay windings may be adjusted as desired by adjusting the position of the adjustable contact 603 on the differential trim resistance 602. If the contact 603 is in the exact electrical midpoint of the resistance 602, both relay windings will have the same amount of current flowing therethrough and will cause their contacts 611 and 612 to close at the same time when the conductivity of the emitter-collector circuit of the control transistor 598 reaches a predetermined value. If the adjustable contact is moved from the electrical mid point the current flow toward the right so that the relay winding 605 will move its contact 611 to closed position and an increased flow of current must take place through the emitter-collector circuit of the control transistor before the sutficient current will flow through the other relay windings 606 to cause it to move its contact 611 to its closed position. This will, of course, occur if the resistance of the thermistor is sufficiently great due to an increased drop in temperature of the air flowing therepast.

The conductivity of the emitter-collector circuit of the control transistor 598 increases as the resistance of the thermistor 571 and the conductivity of the emittercollector circuit of the transistor 590 increases. The con tact 611 when in its closed position connects one side of the relay winding 549 to the positive output conductor 402 through the conductors 615, 616, 617 and 582, the contacts 588, 423 and 425 of the wafer switch W1, if it is in its position wherein the contact 588 engages the contact 423, and the conductors 426 and 427. The other side of the relay winding 549 is connected to the negative output conductor 403, through the conductors 620 and the conductor 537. A diode 622 is connected between the conductor 615 and 620 and therefore across the relay winding 549 to bypass inductive surges.

One side of the winding 565 of the relay 564 is conhectable to the positive output conductor 402 by a conductor 625, the relay contact 612 and the conductors 626 and 582, the contacts 588, 423 and- 425 of the wafer switch W1 when it is in its appropriate position, and the conductors 426 and 427. The opposite side of the winding 565 is connected to the negative output conductor 403 by the conductors 628, 620 and 537. The diode 629 is connected across the conductor 625 and 620, and therefore across the relay winding 565, to bypass inductive surges.

It will now be apparent that if the adjustable contact 603 of the differential trim resistance 602 is so set that the relay winding 605 is in a circuit having a higher resistance than the resistance of the circuit of the relay winding 606 and the air flowing into the chamber 66 when the blower motor is in operation is very cold so that the thermistor resistance is very high, both relay contacts 611 and 612 will be moved to closed position when the wafer switch W1 is rotated counterclockwise to cause its movable contact 423 to engage its contact 588 and its movable contact 510 to engage its contact 586 and thus connect the heater control unit 570 across the output conductors 402 and 403. As a result both sets of heating elements are connected across the main conductors 201, 202 and 203 to provide maximum heating of the air being circulated through the housing chamber 66 by the blower motor. As the temperature of such air rises to a predetermined value, and the resistance of the thermistor decreases to a predetermined value, the conductivity of the emittercollector circuit of the control transistor 598 decreases to such degree that the current flow through the relay winding 606 decreases to such degree that its contact 612 moves to its open position and the second set of heating elements 125d, 125e and 125 is disconnected from the main conductors 201, 202 and 203 thus decreasing the degree of heating of the circulated air since only the first set of heating elements is now connected across the main conductors. When the temperature of the air drawn into the upper chamber rises to a second higher predetermined value, the resistance of the thermistor decreases still further and the current flow through the relay winding 605 decreases to such extent that its contact 611 moves to open position thus causing the first set of heating elements also to be disconnected from the main conductors.

The voltage regulator 515 supplies a regulated voltage across the conductors 421 and 502 and across the conductors 581 and 582, depending upon the position of the wafer switch W1, since a regulated voltage is necessary for the proper functioning of the cool control circuit 420 and heat control circuit 570, The voltage regulator may be of any suitable type such as the series transistor type illustrated having a transistor 700 whose emitter collector circuit is connected in series with the conductors 403 and 514 by conductor 701. The variations in the voltage across the conductors 402 and 701 are amplified by an amplifier circuit which includes the transistors 701, 702 and 703 and a voltage divider bridge which includes the resistances 705, 706 and 707 connected across the conductors 402 and 701 which senses such variations. The structure and mode of operation of the voltage regulator 515 will not be described further since they are well known to those skilled in the art and any suitable voltage regulator may be employed in its place.

The rectifier 404 may also be of any suitable type and includes a transformer 715 whose primary winding 716 is connected across the conductors 201 and 204 by means of the conductors 223, 718, 719 and 234. The secondary winding 720 has one of its sides connected to the positive output conductor 402 through a diode 21 and an inductance 723 and its other side to the negative conductor 403 through a diode 724. A diode 725 is connected between the conductor 402 and the common connection of one side of the secondary winding and the diode 721 while a similar diode 726 is connected between the common connection of the diode 724 and the other side of the 14 secondary winding 720 and the common connection of the inductance 723 and the diode 721. The inductance 723 and a capacitor 728 connected across the conductors 402 and 403 comprise a filter or pulse smoothing network for the output of the rectifier 404.

The electric drive unit or motor 124a which moves the doors 95, 96 and 97 between their horizontal and vertical positions has a pair of windings 730 and 731, the drive shaft 124 being rotated in one direction when the winding 730 is connected across the conductors 402 and 403 and being rotated in the opposite direction when the winding 731 is connected across the output conductors 402 and 403. One side of each of the windings 730 and 731 are connected by the conductor 733, a current limiting resistance 734 and a conductor 735 to the negative output conductor 403. The other side of the winding 730 is connected to the positive output conductor 402 through a limit switch 737 which opens when the drive unit has moved the doors to their vertical positions, the conductor 738, the stationary contact 739 of a relay 740 when its winding 741 is energized and its movable contact 743 is moved to its lower position and the conductor 553. The other side of the winding 731 is connectable to the positive output conductor 403 through the limit switch 744, which is open when the doors are in their horizontal positions and is moved to its closed position as the doors move toward their vertical positions, the conductor 745, the upper stationary contact 746 of the relay 740 when its winding 741 is deenergized, and the conductor 553.

One side of the relay winding 741 is connected to the negative output conductor 403 by the conductors 748 and 407 and its other side is connectable to the positive output conductor 402 by the conductor 751, the stationary contact 752 of the wafer switch W2, the movable contact 753 when it is moved to the position wherein its radially outwardly extending portion 755 engages the stationary contact 752, the stationary contact 757 which is always in contact with the movable contact 753, and the conductors 758 and 427. It will thus be apparent that when the wafer switch W2 is rotated one position to the right, the doors are moved upwardly to their vertical positions. Once their doors reach their vertical positions, the limit switch 737, which may be mechanically movable by the doors or the drive shaft 724 in any suitable manner, opens to deenergize the winding 730. As the doors move toward their vertical positions, the limit switch 744, which is similarly mechanically engageable by the doors or the drive shaft 124, moves to its closed position.

When the relay winding 741 is thereafter deenergized by movement of the wafer switch W2 to another position, the relay contact 743 moves back to its upper position connecting the winding 731 across the output conductors 402 and 403 since the limit switch 744 is now closed an the drive unit now moves the doors to their horizontal positions at which time the limit switch 744 opens. Upon movement of the doors from their vertical towards their horizontal position, the limit switch 737 closes so that if the wafer switch W2 is moved again to position wherein it connects the relay winding 741 across the conductors 402 and 403, the doors will again be moved to their vertical positions.

The movable contact 753 of the wafer switch W2 is also engageable with the stationary contacts 761, 762, 752 and 763 to connect the lamps L1, L2, L3 and L4 across the conductors 402 and 403 to indicate that the apparatus is in its heat, otf, ventilation and cooling operation conditions or modes, respectively. The wafer switch W2 is mechanically linked with the wafer switch W1 so that both rotate at the same time. When the wafer switches are rotated in a counter-clockwise manner to cause the apparatus to heat the air moved through the upper passage 66 of the housing, the movable contact 753 engages the contact 761 to connect the lamp L5 across the conductors 402 and 403. The lamp L5 which indicates that the refrigerant system is in condition 15 for operation is connectable across the conductors 402 and 403 through the conductors 780 and 781, the compressor ready switch 431, the conductor 432, the compressor motor overload switch 434, the conductor 435, the condenser blower motor, the overload switch 436-, the conductor 437, the compressor pressure switch 438, the conductor 439, the other condenser blower motor, the overload switch 440, the conductors 442 and 443, the evaporator blower motor overload switch 445, .and the conductor 447. The lamp L when it is lit thus indicates that the refrigerant system of the apparatus is in condition to operate.

The lamp L6 indicated the condition of the filter 70 being lit when the filter becomes clogged. The operation of the lamp L6 is controlled by a pressure differential switch 785 which senses the pressure differential across the upstream and downstream sides of the filter and closes when the filter becomes unduly clogged and the pressure differential thereacross rises above a predetermed value. The pressure differential swicth 785 may be of any suitable type such as the type commercially available as Model S830A from Minneapolis-Honeywell Controls Co. When the pressure differential switch 785 closes, the filter lamp L6 is connected across the conductors 403 and 402 by the conductors 787 and 789.

In use, when the main conductors 201, 202, 203 and 204 are connected to a three phase alternating current source by a suitable switch (not shown) and an alternating voltage is applied across the primary winding 716 of the transformer 750 of the rectifier 404 since the primary winding is connected across the common main conductor 204 and the conductor 201. As a result, direct current voltage is impressed across the conductors 402 and 403 and if the wafer switches W1 and W2 are in the positions illustrated in FIGURE 6, the lamp L2 lights indicating that the air conditioning apparatus is not in operation even though the main conductors are now connected to a source of alternating current. If the refrigerant system is now in condition for operation and therefore, none of the switches 431, 434, 436, 438, 440 and 445 are open, the lamp L5 is lit. If the three phase alternating current having a frequency in the range of 47 to 63 cycles per second is impressed across the main conductors for at least a predetermined period of time, the frequency selector circuit which includes the inductance 390 and the capacitor 391 causes sufficient current to flow through the heater 392. to cause the bimetallic contact 401 to move its closed position thus energizing the relay winding 384 and moving its contacts 411 and 452 to their upper and lower positions, respectively. The eneugization of the winding 384 of the relay 381 places the control circuit in condition to connect the 60 cycle frequency windings A, B and C of the compressor motor, the condenser blower motors and the evaporator blower motor across the main conductors in the manner described below when the wafer switches .are moved to appropriate positions to cause the operation of either the blower motor alone or of all these motors. If it is now desired to operate the air conditioning apparatus to ventilate a compartment, the wafer switches are rotated to the positions wherein the movable contact 753 of the wafer switch W2 contacts its stationary contact 752 whereupon the lamp L3 is connected across the conductors 402 and 403 and is lit to indicate that the apparatus is in its ventilation mode of operation. Simultaneously, the winding 741 of the door relay 740', which is now connected across the conductors 402 and 403, as the contacts 752 and 753 moves its movable contact 743 to its lower position, thus connecting the winding 730 to the drive unit 124a across the conductors 402 and 403 whereupon the drive unit moves the doors to their upper vertical positions and as soon as they reach such vertical positions, the limit switch 737 opens. At the same time, the engagement of the movable contact of the 459 of the WflffiI Switch. W2 with the contact 458 connect across the winding 315 of the contactor 314 across the conductors 402 and 403 and the contactor .connects the 60 cycle frequency stator winding of the evaporator blower motor across the main conductor in the manner described above. The evaporator motor will now operate as long as the wafer switch W2 is in this position or unless the evaporator blower motor overheats in which case the overload switch 445 opens. If the evaporator blower motor overload switch opens, the blower motor will, of course, cease to operate even though the ventilation light L3 will remain lit thus indicating to the operator some malfunction of the evaporator blower motor.

If it is then desired to stop the ventilation operation, the wafer switches are moved back to the positions shown in FIGURE 6, the contactor 314 opens to stop operation of the evaporator blower motor and the movable contact 743 of the relay 740 moves to its upper position, as its winding 741 is deenergized, connecting the other winding 731 of the door drive unit acnoss the conductors 402 and 403 whereupon the drive unit moves the doors downwardly from their upper vertical positions to their lower horizontal positions. When the doors reach their horizontal positions, the limit switch 744 opens and discon nects the winding 731 from across the conductors 402 and 403.

If it is desired to operate the refrigerant system of the apparatus the wafer switches W1 and W2 are moved to the positions wherein the movable contacts 753 and 459 of the wafer switch W2 engage the contacts 763 and 461, respectively, thus connecting the lamp L4 and the contactor winding 314 across the conductors 402 and 403 to light the lamp and place the evaporator blower motor in operation and wherein the movable contacts 423 and 510 of the wafer switch engage the contacts 422 and 512, respectively, thus connecting the conductor 421 of the cool control circuit 420 to the positive conductor 402 and its conductor 502 to the negative conductor 403 through the voltage regulator 515. If the temperature of the air being moved inwardly into the upper chamber 66 past the thermistor 500 is now above a value which is predetermined by the values of the variable resistances 509 and 507 of the cool control circuit 420, the winding 211 of the contactor 214 is energized due to the closure of the contact 535 and the compressor condenser blower motors are connected across the main conductors 201-204 causing operation of the compressor and of the condenser blower motors which now circulate air through the condenser 141 of the refrigerant system thus causing cooling and liquification of the refrigerant gas which then flows to the evaporator to evaporate therein and thus absorb heat from the air being moved therepast by the evaporator blower. When the temperature of the air being circulated through the evaporator drops to a predetermined value, the contact 535 opens and thus stops operation of the compressor and of the condenser blower motors. If the pressure conditions within the refrigerant gas system on opposite side of the compressor fall out of predetermined ranges or any one of the compressor and condenser blower motors overheats, the pressure responsive switch 458 or the overload switch of such overloaded motor opens and deenergizes the contactor winding 211 since these switches are connected in series with the contactor winding.

If it is desired to heat the air being circulated through the upper chamber 66, the wafer switches W1 and W2 are rotated one position to the left wherein the movable contacts 753 and 459 of the wafer switch W2 engages the stationary contacts 755 and 463, respectively, and thus connect the lamp L1 and the contactor winding 315 of the contactor 314 across the conductors 402 and 403. The 60 cycle stator winding A, B and C of the evaporator blower motor are thus connected across the main conductors 201-204, and the blower motor is placed in operation. Simultaneously the movable contacts 423 and 510 of the wafei switch W1 engage theif stationary contacts '588 and 586, respectively, and thus connect the input conductor 582 of the heat control circuit 570 to the positive conductor 402 and the input conductor 581 to the conductor 403 through the voltage regulator 515. If the temperature of the air being circulated into the upper chamber 566, which is sensed by the thermistor 571, is now below a predetermined value, either the relay winding 605 alone or both the relay windings 605 and 606 are energized to the degree necessary to move their contacts 611 or 612, respectively, to their closed positions, to cause the relays 547 and 564 to connect the contactor windings 350 and 364, respectively, of the contactors 351 and 363 across the main conductors 402 and 403 to cause one or both, as the case may be, of the two sets of the heater elements across the main conductors. The relay windings 605 and 606 will then cause the contacts 611 and 612 to open and close as required to maintain the temperature of the circulated air at a predetermined value.

In the event that the temperature of the air in the upper chamber adjacent the heating elements exceeds a predetermined value, for example, 125 degrees Fahrenheit, the switch 557 opens thus disconnecting the contactor windings 350 and 364 from the main conductors 402 and 403 and thus disconnecting the heater elements from the main conductors.

It will be apparent that if the main conductors 201, 202, 203 and 204 are connected by a suitable switch to a source of three phase alternating current of a frequency .in the range of 380 to 420 cycles per second, the frequency selector circuit which includes the inductance 410 and capacitor 412 cause sufficient current to flow through the heater element 412 to cause the bimetallic contactor 415 to move to its closed position thus causing energization of the relay winding 385 of the relay 382 and in this event when the wafer switches are moved to their appropriate positions, as described above in connection with the operation of the apparatus when a 60 cycle frequence three phase alternating current is impressed across the main conductors 201-204, and thus connect the Winding 250 and 331 of the contactors 251 and 330, respectively, across the conductors 402 and 403 so that the 400 cycle winding A1, B1 and C1 of the compressor and .blowermotors will then be connected across the main conductors as determined by the various switches and control elements of the control circuit. The power factor correcting capacitors are, of course, connected across the main conductors when the contactor 251 is closed.

If due to some malfunction of the relays 381 and 382 the contacts of both of the relays are in their operative positions, which would occur if both windings 384 and 385 were energized at the same time as due to a short circuit, the windings of the contactors 210, 251, 314 and 330 can not be connected across the conductors 402 and 403 regardless of the frequency of the alternating current impressed across the main conductors since the winding of these contactors are connectiable across the conductors 402 and 403 only if the contacts of one relay 381 or 382 are in the positions illustrated in FIGURE 7 and of the other relay in their actuated positions. It will thus be apparent that the frequency selector circuits and the frequency selector relays must all be in proper operating condition to permit energization of the motors and this prevents energization of the stator windings by alternating current of frequencies for which they are not designed. The operation of the windings 350 and 364 of the contactors 351 and 363 which connect the two sets of heating elements to the main conductors 201-204 is independent of the operation of the frequency selector relays 381 and 382 since the resistive heating elements may have alternating current of any frequency flow therethrough without damage thereto. If the blower motor does not operate due to any reason, the temperature of the air adjacent the heating elements will rapidly increase 18 above 125 degrees and the temperature responsive switch 557 will open.

In addition, should the blower motor become overheated and its switch 445 open, the contactor winding 350 and 364 will be immediately disconnected from the conductors 402 and 403 and the contactors 351 and 363 will disconnect the two sets of heating elements from the main conductors.

The bimetallic contacts 401 and 415 will not close upon momentary energization of their frequency selector circuit by transient alternating currents since current must flow through the heating elements 322 and 412 for a predetermined period of time before the bimetlalic contacts are heated to such degree that they move to their closed positions and accordingly the relay windings 384 and 385 and the frequency selector relays therefore are not actuated when alternating voltages, which fall within appropriate frequency ranges, of short duration are applied across the main conductors and therefore across the frequency selector circuits.

It will now be seen that a new and improved control circuit has been provided for an apparatus provided with two sets of electrically energizable means, such as the two sets of stator windings of each of the compressor and blower motors, which are energizable by alternating currents of different frequency ranges.

It will further be seen that the control circuit includes a pair of relay means such as the relays 381 and 382 which are selectively actuated by frequency selector circuits and that one of these relays must be in its nonactuated position and the other in its actuated position in order that the sets of the windings may be individually energized by an alternating current of appropriate frequency ranges.

It will further be seen a new and improved air conditioning apparatus has been illustrated and described having a blower motor 131 for circulating air therethrough; a refrigerant system which includes a compressor for compressing a refrigerant gas, a condenser 141 for cooling and liquefyin-g the refrigerant gas, and an evaporator 70 in which the refrigerant gas evaporates and expands to cool the circulated gas; a heating means such as the heating elements for heating the circulated air; and control means which includes the wafer switches W1 and W2 for placing the blower motor 31, the refrigerant system and the heating means in operation.

It will further be seen that the control means includes means responsive to the temperature of the air being circulated through the apparatus for controlling the operation of the refrigerant system and of the heating means to maintain the air at predetermined temperatures.

The foregoing description of the invention is explanatory only, and changes in the details of the construction illustrated may be made by those skilled in the art, within the scope of the appended claims, without departing from the spirit of the invention.

What is claimed and desired to be secured by Letters Patent is:

1. An air conditioning apparatus including: a housing providing a first chamber and a second chamber; a refrigerant gas cooling system including an electrically energizable compressor for compressing a refrigerant gas, a condenser for cooling and liquefying the compressed gas and an evaporator wherein the liquified gas evaporates and expands, said evaporator being mounted in said first chamber and said condenser being mounted in said second chamber, said housing having a first inlet aperture and a first outlet aperture spaced from each other and opening from the exterior of said housing to said first chamber; first electrically energizable air mov-' ing means for moving air into said first chamber through said first inlet aperture, through said evaporator and to the exterior of said housing through said first outlet aperture, said housing having a second inlet aperture and a second outlet aperture spaced from each other and opening to said second chamber; second electrically energizable air moving means for moving air into said second chamber through said second inlet aperture, through said condenser and to the exterior of said housing through said second outlet aperture, said housing having a connecting aperture providing communication between said first and said second chambers; closure means for closing said first inlet aperture and said connecting aperture; electrically operable drive means for moving said closure means to close said first inlet aperture and simultaneously open said connecting aperture and to open said first inlet aperture and simultaneously close said connecting aperture; and control means for selectively energizing said compressor, said air moving means and said electric drive means, said control means having selector means operable to cause said closure means to open said connecting aperture and close said first inlet aperture and cause operation of said first air moving means, said selector means also being operable to cause said closure means to close said connecting aperture and open said first inlet aperture and cause simultaneous operation of said compressor and both of said air moving means.

2. An air conditioning apparatus including: a housing providing a first chamber and a second chamber; a refrigerant gas cooling system comprising an electrically energizable compressor means for compressing the refrigerant gas, a condenser for cooling and liquifying the compressed gas and an evaporator wherein the liquified gas evaporates and expands, said evaporator being mounted in said first chamber and said condenser being mounted in said second chamber; air heating means in said first chamber, said housing having a first inlet aperture and a first outlet aperture spaced from each other and opening from the exterior of said housing to said first chamber; first electrically energizable air moving means for moving air into said chamber through said inlet aperture, through said evaporator and heating means and to the exterior of said housing through said first outlet aperture, said housing having a second inlet aperture and a second outlet aperture spaced from each other and opening to said second chamber; second electrically energizable air moving means for moving air into said second chamber through said second inlet aperture, through said condenser and to the exterior of said housing through said second outlet aperture, said housing having a connecting aperture providing communication between said first and second chambers; closure means for closing said first inlet aperture and said connecting aperture; electrically operable drive means for moving said closure means to close said first aperture and simultaneously open said connecting aperture and to open said first inlet aperture and simultaneously close said connecting aperture; and control means for selectively energizing said compressor, said air moving means, said electric drive means and said air heating means, said control means having selector means operable to cause said drive means to move said closing means to open said connecting aperture and close said first inlet aperture and simultaneously cause operation of said first air moving means, said selector means also being operable to cause said air heating means to be energized when said first air moving means is operating and said connecting aperture is closed, said selector means also being operable to cause said drive means to move said closure means to close said connecting aperture and open said first inlet aperture and cause simultaneous operation of said compressor and both of said air moving means.

3. An air conditioning apparatus including: a housing providing a first chamber and a second chamber; a refrigerant gas cooling system including an electrically energizable compressor for compressing refrigerant gas, a condenser for cooling and liquifying the compressed gas, and an evaporator wherein the liquified gas evaporates chamber and said condenser being mounted in said second chamber; air heating means mounted in said first chamber, said housing having a first inlet aperture and a first outlet aperture opening to said first chamber at spaced locations; first electrically energizable air moving means for moving air into said first chamber through said first inlet aperture, through said evaporator and said heating means and to the exterior of the housing through said first outlet aperture, said housing having a second inlet aperture and a second outlet aperture spaced from each other and opening to said second chamber; second electrically energizable air moving means for moving air into said second chamber through said second inlet aperture, through said condenser and to the exterior of said housing through said outlet aperture, said compressor and said first and second air moving means each having two op erative means energizable by alternating current of different frequency ranges; an input circuit; and a control cir= cuit having means for selectively permitting connection of one of said operative means of each of said compressor means and said air moving means to said input circuit when an alternating current of one predetermined fre* quency range is applied across said input circuit and for permitting connection of the other operative means of each of said compressor means and said air moving means to said input circuit when alternating current of another predetermined frequency range is impressed across said input circuit.

4. The apparatus of claim 3 wherein said control cin cuit includes selector means for selectively causing simultaneous operation of said first and second air moving means and said compressor means, said heating means and said first air moving means, and of said first air moving means only.

5. The apparatus of claim 4 wherein said control means includes means for controlling operation of said heating and cooling means in accordance with the temperature of the air being moved into said first chamber.

6. The apparatus of claim 5 wherein said control means includes means for preventing operation of said compressor and said second air moving means when said first air moving means is inoperative.

7. The apparatus of claim 6 wherein said control means includes means for preventing operation of both said com pressor and said second air moving means when either of said compressor and said second air moving means is inoperative.

8. The apparatus of claim 3, wherein said means for selectively permitting connection of said operative means across said input circuit includes a pair of frequency selector circuits connected across said input circuit, said frequency selector circuits being responsive to alternating current voltage of different predetermined frequency ranges; first relay means operable by one of said frequency selector circuits when the frequency of the alternating current voltage across the input circuit is within one frequency range for permitting connection of one of said operative means of each of said compressor means and said air moving means across said input circuit; and second relay means operable by the other of said frequency selector circuits when the frequency of the alternating current voltage across the input circuit is within said another predetermined frequency range for permitting connection of the other operative means of each of said compressor means and said air moving means across said input circuit.

9. The apparatus of claim 8, wherein said first'and second relay means have contact means connectable when said first relay means is actuated and said second relay means is not actuated to permit connection of said one of said operative means of each of said compressor means and said air moving means across said input circuit and connectable when said second relay means is actuated and said first relay means is not actuated to permit connection of the other of said operative means of each of said compressor means and said air moving means across said input circuit.

10. An air conditioning apparatus including: a housing providing a first chamber and a second chamber; a refrigerant gas cooling system including an electrically energizable compressor for compressing refrigerant gas, a condenser for cooling and liquifying the compressed gas and an evaporator wherein the liquified gas evaporates and expands, said evaporator being mounted in said first chamber and said condenser being mounted in said second chamber, said housing having a first inlet aperture and a first outlet aperture spaced from each other and opening to said first chamber; first air moving means for moving air into said first chamber through said first inlet aperture and said evaporator and to the exterior of the housing through said first outlet aperture, said housing having a second inlet aperture and a second outlet aperture spaced from each other and opening to said second chamber; second air moving means for moving air into said second chamber through said second inlet aperture, through said condenser and to the exterior of said housing through said outlet passage; a three phase alternating current input circuit; electric motors for operating each of said compressor and said first and second air moving means, said motors each having two stator windings individually connectable to said input circuit and each stator winding of each motor being energizable by alternating current of a different frequency range than the other stator winding of each motor; a pair of frequency selector circuits connected in parallel across one phase of said input circuit, one of said frequency selector circuits being responsive to alternating current of one of said two frequency ranges and the other of said frequency selector circuits being responsive to alternating current of the other of said frequency ranges; first relay means actuatable by one of said frequency selector circuits when the frequency of the alternating voltage across the input circuit is of one of said frequency ranges; and second relay means actuatable by the other of said frequency selector circuits when the frequency of the alternating current across the input circuit is of the other of said two frequency ranges, said first and second relay means having contact means connectable when said first relay means is actuated and said second relay means is not actuated to connect one of said two stator windings of each of said motors to said input circuit and connectable when said second relay means is actuated and said first relay means is not actuated to connect the other of said stator windings of each of said motors to said input circuit.

11. The apparatus of claim 10, wherein the frequencies of the alternating current in said other of said frequency ranges are higher than the frequencies in said one of said frequency ranges and said apparatus includes a plurality of power factor correcting capacitors, said capacitors being connected across said other of said stator windings of said motors.

References Cited by the Examiner UNITED STATES PATENTS 2,332,730 10/1943 Kucher 98-94 2,436,302 2/1948 Hyde et al. 318-200 2,522,286 9/1950 Lehane et a1 27 2,705,770 4/1955 Suhr 318200 2,800,306 7/1957 Freeman 16527 2,886,955 5/1959 Bauman 16548 X 3,009,332 11/1961 Spiegelhalter 62-180 3,040,543 6/1962 Atchison 62-181 3,194,028 7/1965 Bell 62-180 ROBERT A. OLEARY, Primary Examiner.

M. A. ANTONAKAS, Assistant Examiner.

Claims (1)

1. AN AIR CONDITIONING APPARATUS INCLUDING: A HOUSING PROVIDING A FIRST CHAMBER AND A SECOND CHAMBER; A REFRIGERANT GAS COOLING SYSTEM INCLUDING AN ELECTRICALLY ENERGIZABLE COMPRESSOR FOR COMPRESSING A REFRIGERANT GAS, A CONDENSER FOR COOLING AND LIQUEFYING THE COMPRESSED GAS AND AN EVAPORATOR WHEREIN THE LIQUIFIED GAS EVAPORATES AND EXPANDS, SAID EVAPORATOR BEING MOUNTED IN SAID FIRST CHAMBER AND SAID CONDENSER BEING MOUNTED IN SAID SECOND CHAMBER, SAID HOUSING HAVING A FIRST INLET APERTURE AND A FIRST OUTLET APERTURE SPACED FROM EACH OTHER AND OPENING FROM THE EXTERIOR OF SAID HOUSING TO SAID FIRST CHAMBER; FIRST ELECTRICALLY ENERGIZABLE AIR MOVING MEANS FOR MOVING AIR INTO SAID FIRST CHAMBER THROUGH SAID FIRST INLET APERTURE, THROUGH SAID EVAPORATOR AND TO THE EXTERIOR OF SAID HOUSING THROUGH SAID FIRST OUTLET APERTURE, SAID HOUSING HAVING A SECOND INLET APERTURE AND A SECOND OUTLET APERTURE SPACED FROM EACH OTHER AND OPENING TO SAID SECOND CHAMBER; SECOND ELECTRICALLY ENERGIZABLE AIR MOVING MEANS FOR MOVING AIR INTO SAID SECOND CHAMBER THROUGH SAID SECOND INLET APERTURE, THROUGH SAID CONDENSER AND TO THE EXTERIOR OF SAID HOUSING THROUGH SAID SECOND OUTLET APERTURE, SAID HOUSING HAVING A CONNECTING APERTURE PROVIDING COMMUNICATION BETWEEN SAID FIRST AND SAID SECOND CHAMBERS; CLOSURE MEANS FOR CLOSING SAID FIRST INLET APERTURE AND SAID CONNECTING APERTURE; ELECTRICALLY OPERABLE DRIVE MEANS FOR MOVING SAID CLOSURE MEANS TO CLOSE SAID FIRST INLET APERTURE AND SIMULTANEOUSLY OPEN SAID CONNECTING APERTURE AND TO OPEN SAID FIRST INLET APERTURE AND SIMULTANEOUSLY CLOSE SAID CONNECTING APERTURE; AND CONTROL MEANS FOR

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