US1851998A

US1851998A - Temperature compensator

Info

Publication number: US1851998A
Application number: US471944A
Authority: US
Inventors: Yearsley Eugene Wilson
Original assignee: Otis Elevator Co
Current assignee: Otis Elevator Co
Priority date: 1930-07-31
Filing date: 1930-07-31
Publication date: 1932-04-05
Anticipated expiration: 1949-04-05

Description

April 5, 1932. E. W. YEARSLEY LSSL TEMPERATURE COMPENSATOR Filed July 31, 1930 4 sheets-Sheet l ELEVATOR N 1 ELEVATOR N 2.

CONDUIT CONTROL CONTROL TEMPERATURE COMPENSATING PANEL PANEL MECHANISH omvmc MOTOR ELEVATOR HmsTms DPWING MOTOR HOISTING BHEAVE SHEAVE l2 "2 EXCITER GENERATOR Emu- GENERATOR I F nAKEna s AKE n3 t H vd v T4 1 T 1 1 /i V 72 HOISTING ROPES HOISTING RoPEsj- 3AFETY SWITCH 5b SAFETY SWITCH 56 START 5WlTC H CARSWITCH 5 5 STARTSWITCH j 50 CAR CAR COUNTERWHGflT I COUNTERWEIGhT naw- W INVENTOR BY ATTORNEY p i 5, 1932- E. w. YEAl RSLE Y 1,851,998

TEMPERATURE COMPENSATOR Filed July 31, 1930 4 Sheets-Sheet 4 u i I II V J 0%8 R4 19 55 0 null I 048 P49 5'50 II INVENTOR ATTORNEY Patented Apr.- 5, 1932 PAT FFlE

EUGENE WILSON YEARSLEY, F BROOKLYN, NEW YORK, ASSIGNOR TO OTIS ELEVATO B COMPANY, OF NEW YORK, N. Y., A CORPORATIONOF NEW EY TEMPERATURE comrnnsaron Application filed July 31, 1980. Serial 310. $71,944.

The invention relates to control systems and especially to control systems for elevators.

In apparatus of this character, especially in high speed elevator installations, one of the problems that has been experienced is to secure uniform operation of the elevator car.

The temperatures of the electrical apparatus,

in particular such units as the elevator hoistm ing motor and, in installations employing the Ward Leonard system of control, the motor generator set, vary considerably due to service conditions. The electrical apparatus is usually comparatively cold when the elevator to is put in service in the morning and heats up to a maximum at some time during the day and then cools down when the elevator is partially or wholly put out of service. The changes in temperature oi the windings of the so drive units cause changes in the operating performance of the elevator. The changes in' temperature of certain control apparatus may also ailect the operating performance of the elevator. llhese changes in performance have been particularly noticeable in certain installations in which automatic stops are made and in certain installations in which self-levelling is employed.

The principal object of this invention is to obviate the effects of temperature changes and insure uniform operation of the elevator car.

(lne feature of the invention is to obtain uniform operation of an electrical drive unit regardless of the heating of its windings.

Another feature of the invention is to obtain. uniform operation of an elevator car operated by a comloination of drive units, w regardless of the heating of the windings W of such units, by controlling the field strength one or mo-e of said units. Another feature of the invention is to obtain unitorm operation on? elevator car by controlling the operation at the switching;

mechanism which controls retardation and acceleration of the car in such manner as to compensate forchanges in temperature in one or more of the drive units or or the switchso ing mechanism itself.

Other features and advantages will becomev strength of the magnetic field of such unit or units by employing resistance electrically connected with the winding or windings thereof and varying the value or" resistance in accordance with the changes in temperature.

For the purpose of illustrating the genus of the invention, a typical concrete embodiment is shown in the accompanying drawings in connection with a Ward Leonard system of control.

In the drawings:

Figure l is a schematic representation of an elevator installation illustrating the adaptation of the invention to a plurality of elevators;

l 'gure 2 is a simplified schematic diagram of the power and control circuits for one elevator;

Figure 3 is a diagrammatic represen ation of the control panel for one elevator, illustrating the relation oi: the coils and contacts and other component parts of the switches employed in the control system; and

Figures 4-, 5 and 6 are diagrammatic views illustrating further applications the in vention.

Referring to Figure l in which the various parts of two elevator systems are indicated lay legend, the elevator car and counterweight of elevator No. l are raised and lowered the elevator motor. The hoisting cables con nected to the car and counterweig t over the hoisting sheave in accor the principles of the traction l he compensating cables are connected the bottom or the car and counterweight illustrated as being tensioned by a comp ing sheave. The elevator motor is of rect-current type and is supplied with current at a variable voltage by a direct-current till Til

let?) generator in accordance with the principles of the Leonard system. The driving means for the generator is preferably an electric motor, and maybe of either the direct-current or alternating-current type.

The temperature compensating mechanism for elevator No. 1 is mounted on the control panel for that elevator. The details of this mechanism are not illustrated in this figure and will be described later. Briefly, however, this mechanism comprises temperature responsive elements placed so as to .be subject to the temperature of the drive or control unit for which it is desired to provide compensation or which is to be utilized to efiect compensation and connected to compensating mechanism on the control panel. According to the embodiment chosen for purposes of description, bulbs containing expansible fluid are employed as the temperature responsive means and these bulbs are connected to the compensating mechanism by tubes.

This arrangement is indicated schematically for efi'ecting compensation for variations in temperature of windings of the elevator motor and its supply generator by connecting tubes leading from each of these units to the control panel. This showing is simply illustrative for the principles of the invention are applicable to other parts of the system as will be shown by later description.

' Inasmuch as in most elevator installations in which more than one elevator car is employed to serve the building and particularly in the case of elevators in a group, the elevators are usually placed in service in the mornings and discontinued from service in the evenings about the same time and average about the same in the amount of operation, the temperature compensating mechanism for one elevator may be employed to effeet compensation for units of the other elevators. Such arrangement is illustrated in Figure 1 for two elevators, it being understood that the mechanism may be employed for more than two elevators so long as the operating conditions for the elevators remain substantially the same. The connection of the temperature compensating mechanism for elevator No. 1 to the compensating control switches for elevator No. 2 is indicated in Figure l by a conduit which extends between the control panels and through which the connecting wires extend. 0n the other hand, each elevator may have its own compensating mechanism, if desired.

The control panel for elevator No. 1 with its various switches is illustrated in Figure 3. No description of the switches or the panel will be given at this time, as it is believed that their construction and operation will be sufiiciently understood from the description which follows,

Reference may now be had to Figure 2 which illustrates diagrammatically the various control and power circuits. In this figure, the coils and contacts of certain of the electromagnetic switches are not shown in them assoc1ated positions, a simplified diaillustrated in cross-section.

The various electromagnetic switches employed in the control system chosen to illustrate the principles of the invention are designated as a whole as follows:

A-Potential switch B-Up direction switch C-Down direction switch E, FAccelerating switches GMaintaining relay H-Brake switch J Minimum current field relay K-Driving motor starting switch L- Driving'motor running switch M,Driving motor starting relay N, O, PGenerator field compensating relays Q, R, S-Elevator motor field compensating relays T, U, V-Accelerating mechanism compensating relays 1 ZSpeed re lating switch The letter is employed to designate an inductance coil.

Throughout the description which follows, these letters, in addition to reference numerals, will be applied to the parts of the above designated switches. For example, B 119 will indicate that the contacts are on the up direction switch, while operating coil A 53 will indicate that the coil operates the potential switch. This will be made clear by reference to Figure 3. In the case ofthe numerals employed in the control system, the.

gram being employed wherein the coils and from left to right, downwardly of the sheet of drawings. The arrangement of the. numerals in -this sequence facilitates the ready location of any element referred to in the description. The electromagnetic switches are shown in their deenergized positions.

The driving motor of the motor generator set is illustrated as of the alternating current type. The stator windings are designated 164, and 166 and therotor is designated 167. The generator driven by the driving motor is of the variable voltage direct current type. The armature of the generator is designated 127, its separately excited field winding 123 and its series field winding 126. The series field winding'126 may have any to the elevator motor field desirednumber of turns to efiect the desired compounding of the generator to compensate for variations-in load. The driving motor also drives an exciter for supplying current to the separately excited field windings of the elevator motor and generator and also to the operating coils of various control switches. The armature of the exciter is designated 22, its shur field winding 21 and its series field winding 20. The armature of the elevator motor is designated 128 and the separately excited field winding of the elevator motor is designated 23.

Acceleratin resistances 156, 157 and 158 are provided 501' the driving motor. Resistance 117 is-provided for controlling the voltage applied to the generator separately excited field winding 123. Resistance 117 is arranged in steps to be controlled by the accelerating switches to bring the generator voltage up to full value. Resistance 32 is provided for controlling the voltage applied winding 23.

In addition to resistance 117, a resistance 118 is provided for controlling the voltage applied to the generator field winding 123. Resistance 118 is also arranged in steps to be controlled by compensating relays N, O and P subject to the control or the temperature compensating mechanism unit for the genf erator field winding. Similarly, an additional resistance 33'is rovided for controlling the voltage applie to the elevator motor eifected. The

field winding 23. This resistance also is arranged in steps to be controlled by compensating relays Q, R and S subject to the control of the temperature compensating mechanism unit for the elevator motor field winding. Additional compensating resistances 69' and 85 are provided for the accelerating switches E and F, resistance 69 being connected in series with the actuating coils of these switches while resistance 85 is adapted to be connected in a dischar e circuit for the coil of accelerating switch The temperature compensating mechanism employed is illustrated as three separate units, one for the elevator motor field winding 23, another for the generator field winding123 and the remaining one for the accelcrating switches. These units are illustrated only diagrammatically and their construction may vary considerably from that indicated in the drawings. Referring to the compensating mechanism unit for the elevator motor field winding, for example, this unit comprises a pivoted switch lever 36 provided with a contact segment 41 on its outer end.

Stationary contacts

44, 43 and 42 are positioned to be engaged by contact segment 41 as movement of lever 36 about its pivot is lever is actuated by a bellows device 40 which is connected to the lever by a slot and pin connection. A spring 39 is 5 provided for biasing the contact lever into 'tacts L 159, L 160 position in which its segment 41 is disengaged from its stationary contact. An adjusting screw 38 regulates the pressure of this sprin and thus affords an adjustment for the initial operating point of the unit. The bellows to a bulb 24 illustrated as arranged in the field winding 23. The actual location of bulb 2A in the elevator motor may be varied, it being understood that any location is suitable so long as the bulb is subject to temperature of the motor, particularly to the temperature of the field winding. The bulb, connectingtube and bellows device, contain fluid of a type such as will expand due to increase in temperature. Oil may be found suitable for this purpose. The bulb 124 for the compensating unit for the enerator field winding. is similiarly locate in the generator so as to be subject to temperature changes. The bulb 7 8 of the unit for the accelerating switches is positioned to be subject to the temperature of one of the switch coils and may be located within the coil itself as illustrated in Figure 3. v

The various safety switches, limit switches and door and gate contacts may be employed, some of which have been omitted for convenience of description; others will he reerred to in connection with the description of the various circuits and in connection with the operation of the system.

It will be assumedthat the car is stationary at a floor with the car gate and batchway door at that floor open and that the motor generator set is at rest. To start the motor generator set in operation, the start switch 150 within the car is closed. This causes the operation of starting its actuating coil M 151 across alternating

current mains

145 and 146 through knife switch 152, this knife switch being on the control panel for operation by the penthouse attendant. Relay M engages its contacts M 147 to connect coil K 148 of the starting switch across alternating

current mains

144 and 145 through contacts L 149 of running.

switch L. Switch K 0 rates to engage its contacts K 153, K 154 and K 155, connecting the stator ,windings of the driving motor to the alternating current mains through resist ances 156, 157, and 158. Relay M also engages its contacts M 163 to connect coil L 162 of the running switch across the stator windings of the driving motor so that, as the driving motor comes up to speed and the voltage applied to coil L 162 increases to a certain value, switch L operates to engage its conand L 161. This connects the driving motor directly to the alternating current ma ns. Switch L also separates its contacts L 149 to deenergize coil K- 148 of starting switch K, disconnectingresistances 156, 157- and 158 Switch L is providedw ithadditional contacts L 25 and L 54; Contacts relay M by connecting device is connected by a tube 0011 J 27 does not receive current until the L54 are arranged in the circuit with the actuating coil A 53 of the potential switch,

and their purpose will be explained. later.v

exciter E. M. F. is built up to substantially full value. Furthermore, until the elevator motor field builds up to substantially full for the value, this field having a'certain time constant, the current supplied to coil J 27 is of a. Y cient value to cause the operation of relay J. As soon as the elevator motor field builds up to substantially full value, relay J operates to engage its contacts J in the circuit for coil A. -53 of the potential switch. This completes the potential switch actuating coil circuit, the circuit being through potential switch contacts A 51 and safety switch 56 in the elevator car. Thus, the operation of the potential switch is prevented until the exciter E. M. F. has built up substantially to full value and until the elevator motor field has built up tosubstantially full value.

The potential switch operates to engage its contacts A 57 and A 58,.preparing the circuit and various control circuits. Potential switch A also separates its contacts A 51 to insert a cooli resistance 52 in series with actuating coil 53. This is the condition of the circuits with the motor set in operation and the elevator car stopped at a floor with the door and gate open. 7

Assume that the car gate and hatchway.

ating coil B 88 of the up direction switch and actuating coil H 94 of the brake switch through door contacts D092 (a single set of contacts being illustrated in lieu ofthe several pairs ofdoor contacts connected in series relation), gate contacts GC 93, down direction switch contains C 87 and safetyswitch 56. Switch B operates to engage its contacts B 119 and B 131. This completes a circuit for V the generator separately excited field winding 123 through resistances'117' and 118 and actuating coil G 122 of the maintaining relay.

enerator separately excited field menses Switch B also engages its contacts B 101 to prepare a circuit or auxiliary coil B 102 for the up direction switch and auxiliary coil H 105 for the brake switch and separates its contacts 13 96 in the circuit for actuating coil G 97 of the down direction switch. Switch H operates simultaneously with switch B to engage its contacts H 108, completing a circu t for the brake release coil 112 throu h contacts 110 in a position to be operated y the brake mechanism. Switch H also separates its contacts H 125 to disconnect the generator field winding 123 from across the generator armature 127.

Voltage being applied to the generator field winding 123 and the brake release coil 112 being energized to release brake 113, the elevator motor starts the car in the up direction. The brake, upon being released, efiects the separation of contacts 110 to insert cooling resistance 109 in circuit with brake release coil 112.

Switch His provided with additional contacts H which engage to prepare a circuit for the actuating coil E 77 of the first accelcrating switch. This circuit is completed upon car switch segment engaging contact 81 and is through resistance 69, inductance coil X 73 and safety switch 56. The operation of switch E is delayed due to the action of inductance coil X 73. Upon operation, switchE engages itspontacts E 114 to shortcircuit a step of generator field resistance 117. This aincreasesl the voltage applied to the generator separa tely excited field winding, thus increasing the generator voltage and the speed of the elevator motor. Switch E also engages its contacts E 107 to complete the circuit for the auxiliary coils B 102 and H 105 of the up direction switch and brake switch res ctively. Switch E is provided with additional contacts E 5 which engage to prepare a circuit for the actuating coil F 74 of the last accelerating switch. This circuit is completed by the engagement of car switch segment 90 with stationary contact 76 and .is through resistance 69, inductance coil X 73 and safety switch 56. The operation of switch F also is delayed by the action of inductance coil X 73. U on operation, switch F engages its contacts 116 to shortcircuit the remaining step of generator field resistance 117. This increases the excitation of the generator field winding to full value, increaslng the generator voltage and the speed of the elevator motor. Switch F also separates its contacts F 29 in shunt-to re; sistance 32 in the circuit for the elevator motor field winding 23. The separation of these contacts has no effect at this time inasmuch as contacts Z 30 of the speed regulatin switch Z are engaged. The actuating coil 129 of switch Z is connected across the generator armature 127 so as to be subject to generator voltage and is set to cause the operation of switch Z upon the enerator voltage increasing to substantially lull value.

Upon operation, switch Z separates its contacts Z to insert resistance 32 in circuit with elevator motor field winding 23. This weakens the elevator motor field causing the elevator motor to increase its speed to full value.

The starting of the car in the down direction is accomplished in a similar manner and need be only briefly described. The car switch is moved in the opposite direction to cause the engagement of segment 90 with

contacts

95, 98, 99 and 100. The actuating coil C 97 of the down direction switch C is energized instead of that of the up direction switch. This switch is provided with an auxiliary coil C 104 and contacts C 130, C 120, C 103 and C 87 corresponding respectively with coil B 102 and contacts B119, B131,B 101 and B 96 of the down direction switch. It is to be noted that the circuit for coil C 97 passes through contacts B 96 of the up direction switch while the circuit for coil B 88 passes through contacts 0 87 of the down direction switch. These contacts serve as electrical interlocks as is understood in the art. Me-

chanical interlocks may also be provided on the direction switches as indicated in Fi ure 3. The other circuits and operations incident to starting the car in the down direction are believed dbvious from previous description.

It is to be noted that the car switch may be thrown to full on position in either direction rather than moved in steps in which event sequence in the starting operations is insured by the action of inductance coil X 73 and the interlocks provided by contacts H 80 and contacts E 75.

To stop the car, the car switch segment may either be returned immediately to ofi position or may be returned to off position. in steps.

As it is believedthat the operation of stopping the car by a step-by-step return of the car switch will be obvious from the description of stopping the car by the immediate return of the car switch segment to neutral, the latter operation will be described. Assuming operation in the up direction, the return of the car switch segment to neutral breaks the circuit for coils F 74, E 77, B 88 and H 94 of the accelerating switches F and E, up direction switch B and brake switch H respectively.

Switch F drops out immediately, causing the reengagement of its contacts F 29 and the separation of its contacts F 116. Con-- tacts F 29' short-circuit resistance 32, increasing the elevator motor field strength to full value for the slow down operation. The

separation of contacts F 1.16 reinserts a step of resistance 117 in circuit with generator field winding 123. This reduces the excitation of the generator and therefore the generator voltage, reducing the speed of the ele vator motor.

Switch E does not drop out immediately, its action being delayed by the efiect of inductance coil X 73 and discharge resistance 86. Switch E, upon returning to denergized position, separates its contacts E 7 5, E 11a and E 10?. Contacts E 7 5 are in circuit with coil F 74, switch F having already returned to deenergized position. Contacts E llreinsert the remaining step of resistance 11? in circuit with the generator field winding 123. This further reduces the excitation of the generator and therefore the generator voltage, bringing the elevator motor down to slow speed.

Switches B and H do not drop out on deenergization of their actuating coils B 88 and H 94, they being maintained in operated condition by auxiliary coils B 102 and H 105. Contacts G 106 of themaintaining relay G are arranged in parallel with contacts E 10'? in circuit with auxiliary coils B 102 and H 105 so that these coils are maintained energized so long as either contacts E 107 or contacts G 106 are in engagement. The actuating coil G 122 of maintaining relay G is in circuit with the generator field winding 123 and is set to cause the engagement of contacts G 106 when the generator field builds up to a certain value. The rate at which the generator field strength decreases during retardation is controlled by discharge resistance 121 and therefore the rate at which the current in coil G 122 decreases during retardation is also controlled by discharge resistance 121. The auxiliary coils B 102 and H 105 aretherefore maintainedenergized during slow down of the elevator motor until switch E separates its contacts E 107 and until the generator field strength has decreased to a sufiiciently low value at which the current in coil G 122 is no longer capable of maintaining contacts G 106 in engagement.

Upon deenergization of auxiliary coils B 102 and H 105, the up direction switch and brake switch return to deenergized positions. Switch B separates its contacts 13 119 and B 131, disconnecting the enerator field winding from the exciter an switch H separates its contacts H 108, deenergizing brake release coil 112. Thus, the generator field being disconnected from the exciter and the brake tor to a stop. Switch" B also separates its contacts B 101 in the circuit for auxiliary coils B 102 and H 105 of the up direction switch and brake switch respectively andseparates its contacts B 96 to prepare the circuit for the down direction switch coil 0 97.

Switch H also separates its contacts H 80 in circuit for coil E 7 7 of accelerating switch E and reenga esits contacts H to reconnect generator eld winding 123 across the generator armature 127. The connection of generator field winding 123 to the generator ar mature lo contacts H 125 is of such polarity as to sen current through field win vided with contacts designated 26 arranged in shunt to elevator motor field resistance 32.

\ These governor contacts close to short-circuit this resistance in the event that the motor overspeeds above a certain amount, thus increasing the elevator motor field strength,

thereby reducing the speed of the elevator motor. I

A safety switch 56 is arranged in the car and is employed to stop the car under emergency operating conditions; The pulling of 7 this switch deenergizes actuating coil'A 53 of the potential switch, resulting in the disconnection of the generator field winding fromithe enciter and the application of the brake to bring the elevator car to an immediate stop. i v

The drlving motor may be stopped by opening start switch 150 in the car. This deenergizes the actuating coil M 151 of starting reay li/l'. Relay M, in turn, separates its contacts M 163 to deenergize actuating coil L 162 of the running switch. The running switch thereupon separates its contacts L 159, L 160 and L 161 to disconnect the stator windings of the driving motor from the? alternating current mains.

In the above description, it was assumed that the driving motor and elevator motor were startedup after a period of shut-down,

such as over night, and that the driving motor, generator, exciter, elevator motor and control apparatus were cold. Assume, however, that the temperatures of the windings of the drive units increase due to continuous operation. The driving motor, being of the alternating current induction type, is substantially unafiected by any increase in temperature of the stator windings or rotor bars so that this increase in temperature does not afi'ect the speed of this motor. However, the

heating of the windings of the generator and elevator motor afiects the operation of the system. The heating of the separately excited field windin 123 of the generator causes the resistance of winding to increase and therefore cuts down the amount of current fiow therethrough'for a iven application of voltage. Similarly, the eating of the separately excited field winding 23 of the elevator motor causes the resistance of this winding to increase and therefore cuts down the amount of current flow therethrough for a given application of voltage. The increased narrate elevator motor for a given load a plied there- I v The increase in resistance 0 the elevator motor field winding decreases the elevator motor field strength, thus tending to Increase the speed of the elevator motor for a given load applied thereto. These two changes in f resistance tend to counteract each other to provide constant speedof the elevator motor for-a iven load thereon but such counteraction 1s not suficient to give the same operating speed as if the motor and generator were cold owing to the difierence in characteristics of the generator and elevator motor and to the fact that the elevator motor field is energized all of the time that the elevator car is in service, whereas the generator field is deenergized when the elevator car is at a standstill. Furthermore, such decrease in the strength of the elevator motor field-and generator field afi'ects the torque of the elevator motor. s'lhe heating of the exciter, due to its continuous operation while the armature and a further decrease in the field strength of the elevator motor. The resistance of the armatures of these various machines also changes due to heating, thereby further afiecting the operation of the elevato'r motor. The efiects of these resistance changes of the windings of the various machines may be obviated by the employment of compensatin resistances controlled in accordance with t e principles of the invention. In the control system illustrated, compensating resistance 33 is provided in series with elevator car is in service, also afiectsthe value F ice the elevator motor field winding 23 and compensating resistance 118 is provided in series with the generator field winding 123. Each of these resistances is shown as arranged in three steps adapted to be successively shortcircuited by compensating relays. The circuits for the actuating coils of these relays are controlled by the contact elements of a compensating mechanism unit, one for the elevator motor and one for the generator as previously described.

As the elevator motor field windin heats and its resistance increases, the uid in bulb 24: expands, acting through the bellows device 40 to move contact segment 41 into engagement with stationary contact 44. its

accuses This completes a circuit for coil Q of elevator motor compensating relay Q. This relay operates to engage its contacts Q 48, short-circuiting a step of resistance 33. The value of this step of resistance is such as to compensate for the increased resistance of the motor field winding 23 and the decreased voltage of the exciter. Upon further increase in the heating of the field winding 23, segment 4L1 is moved into engagement with contact 43 to energize coil R 46 of compensating relay E. This relay engages its contacts R .19 to short-circuit another step of resistance 33. Similarly, upon further heating of the elevator motor field winding and upon such winding reaching substantially its maximum temperature for the particular installation, coil S 47 is energized to efi'ect the engagement of contacts S 50 of the third compensating relay S. This short-circuits the remaining step of resistance 33. The value of each of the last two steps of resistance 33 is chosen to give the desired compensation as in the case of the first step. I

As, the generator heats up, the compensating mechanism unit for the generator operates in a similar manner to effect the successive operation of relays N, O and P. As the fluid in bulb 124: expands, bellows device 143 .moves lever 1 12 about its pivot to efiect the successive engagement of segment 141 with

contacts

140, 139 and 138. This causes the,

successive energization of coils N 135,0 136 and P 137. The energization of the coils causes the successive engagement of contacts N 132, O 133 and P 134 respectively to shortcircuit compensating resistance 118 in steps. The values of these steps of resistance 118 are chosen so as to compensate for the decreased voltage of the exciter, the increased resistance of the generator field windings and the increased resistance of the elevator motor and generator armatures.

It is to be understood that the compensating mechanism units may be arranged to control the compensating resistance In any desired number or steps, three being shown merely for convenience of illustration.

With the compensating arrangement for the generator and elevator motor as above described, itwill be seen that by proper selection or resistance values and proper adjustment of V the compensating mechanism units, uniform operation may be obtained, regardless of the load in the elevator car, direction of travel of the car or temperature of the windings of the various drive units. That is, by the compensating arrangement for the elevator motor field winding, 'the field strength of the elevator motor may be maintained substantially constant, thus providing a constant field for the elevator motor, while by the compensating arrangement for the generator fieldwinding the current flowing through the elevator motor armatu re may be caused to be the same for the same load on the elevator motor. Thus, the torque of the elevator motor, which is proportional to the elevator motor field and armature current may be rendered inde endent of temperature conditions and uni orm speed of the elevator motor obtained.

The arrangement of the compensating mechanism and resistances as above described also insures the same acceleration and retardation for the same load on the elevatormotor. This is due to the fact that the torque is independent of temperature variations. In this connection, it is to be noted that compensating resistance 33 is arranged in the elevator motor field winding circuit in such a position so that it is eii'ective to control the field strength of the elevator motor during acceleration and retardation as well as during full speed operation.

The accelerating mechanism may be utilized as an aid to obtaining uniform operations of the elevator car. This may be done by changing the timing of the accelerating switches by means of compensating resistance and compensating mechanism such as described for the generator and elevator motor field windings. Such arrangement of resistance andmechanism is illustrated in Figure 2 of the drawings wherein the bulb 78 containing the expansible fluid is arran ed with n the operating coil of acceleratmg switch E. It is to;be noted that two co pensating resistances are provided for coil E 77, resistance 69 being arranged in series relation with the coil and resistance 85.being arranged for connection in series with the discharge resistance 86 for the coil. Resistance 69 is also arranged in the circuit for the actuating coil of switch F so that this switch, as well as switch E, is controlled by the compensating mechanism for theacceleration. In order that the manner in which the accelerating mechanism may be utilized to aid in obtaining uniform operation may be readily understood, assume, for example, that the compensating arrangement for the elevator motor field winding 23 is arranged incident with the heating of the elevator motor field winding, the coil of switch E also heats up through numerous periods of energization so that the expanding fluid in bulb 78 acts through tube 68 to cause bellows device 67 to move lever 66 into position where its contactsegment 65' engages contact 64. This energizes coil V 61 of compensating relay V.

- Relay Voperates to engage its contacts V 72 and to separate its contactsV 84. This shortcircuits one step of resistance 69 and inserts a step of resistance 85 in series with discharge resistance 86. The value of the step of resistance 69 is such as to provide quicker operation of switches E and F during acceleration. The insertion of the step of resistance 85 in the discharge circuit for coil E causes switch E to return more quickly to deenergized position during retardation. A similar effect is had upon engagement of segment with

contacts

63 and 62 to energize coils U 60 and T 59. Contacts U 71 and T short-circuit additional steps of resistance 69, contacts U 83 and T 82 insert additional steps of resistance 85 in the discharge path of coil E 77.

The quicker operation ofaccelerating switches during acceleration and retardation as described compensates for the tendency of the elevator motorto develop less torque as the resistance of its field winding'increases. It is to be understood that resistance 85 and contacts T 82, U 83 and V 84 may be omitted if the desired timing of switch E in dropping out is obtained as a result of the increased res stance of its coil due to heating.

The accelerating mechanism compensating arrangement may be employed as an aid to obtain uniform operation with compensating resistance 33for elevator motor field winding 23 arranged in the position illustrated inas much as it may be employed to correct any errors present due to adjustments of the other compensating arrangements. The accelerating mechanism compensating arrangement mayalso be employed alone, if desired, to control acceleration and retardation. In any of these arrangements, by employing a grea er number or" accelerating switches controlled by the compensating mechanism, ver satisfactory compensation can be obtaine The accelerating mechanism com en'sating arrangement may also be employe to maintain aconstant timing of the acceleratingv switches, should the heating of the coils of these switches be sutficient to cause enough change in theirimpedance to vary the timing. Such arrangement may be utilized either with or without the compensating arrangement shown in Figure 2 for the elevator motor field winding and generator field winding. In a system in which compensation such as shown is provided for the generatcr and elevator motor field windings and in which the timing of the accelerating switches tends to vary due totemperature changes, the employment of temperature compensating mechanism to maintain the't'iming of the accelerating switches constant insures the same-acceleration and retardation for the same load on the elevator motor. in the event that the compensating accelerating aeaaees clude resistance 69. The value of resistance 69 would be made such as to give the desired timing of the accelerating. switches under conditions where the system was started up cold. Thus, as the temperature ofcoil E 77 increases, the steps of resistance 69 would he cut out in sequence. steps would be such as to com ensate for the change in resistance of coils 77 and F 74 so that the timing of .these switches in pulling in remains the same and the timing of switch E in dropping out also remains the same. I

The compensating arrangement might also be employed to vary the value of inductance of coil X 73, if desired.-

The values of these Y Itis to be noted that coil F 74 is not subject I to the compensating mechanismin the dropping out of switch F inasmuch as it is usuall desired to have the last accelerating'switc drop out'immediately the circuit for its coil is broken. The compensating arrangement V for the accelerating mechanismarranged to provide umform acceleration and retardation as above described is particularly useful in systems whereinthe starting of the car is controlled by a single operation, as for ex.-

. ample in the system illustrated, by throwing the car switch immediately to full on position. The retardation compensation obtainedis particularly useful in systems such as described under conditions where the sto ping of the car is edected by returning t e carv switchimmediately to neutral position.

In the control system illustrated, only two accelerating switches are shown. It is to he understood, however, that any number of accelerating switches may be employed depending upon the requirements ofthe partic-- ular installation. Also, other types of accelerating mechanism may be utilized, for

example, a motor operated rheostat in which the operating motor runs in one direction for.

the accelerating operation and in theother direction for the retarding operation. With such arrangement, the compensating resis ances, relays and associated mechanism may be arranged to control the value oi? resistanc'eof the motor field circuit and the bulb placed within the operating motor so as to correctly register temperature changes therein. r

rangement for the} accelerating mechanism is employed to vary the acceleration and relin the event that the compensating ear-- tardation, the bulb for bellows device 67 may be positioned at some other point, as for example .in the elevator motor. The compensating arrangement. for the accelerating mechanism may be omitted entirely and the desired operation obtained by properfadajustments' of the compensating arrangements ance are designated 178, 177 and 178. The

operating coils of the compensating relays are not shown in this figure, nor are the compensating mechanism units shown; It is to be understood," however, that the bulb for the exciter compensating mechanism may be arranged in the exciter, a bulb designated 179 being illustrated in this figure as arranged in the exciter shunt field winding 21. The compensating relays for the exciter are actuated as the exciter temperature increases to successively short-circuit the steps of compensating resistance 17 5. These steps may be adjusted to provide constant terminal voltage of the exciter so that the steps of resistonce '33 for the elevator motor field winding 23 may be adjusted to maintain uniform resist-ance oi": the elevator motorfield winding circuit and the "steps of resistance 118 for the 7 generator field winding may be adjusted to compensate for increase in resistance of the generator field windings and generator and elevator motor armature windings.

The principles of the invention are also applicable to systems in which a direct current driving motor is employed for driving the generator. Such arrangements are illustrated in Figures 5 and 6 of the drawings. Both Figures 5 and 8 are diagrammatic as in the case of Figure 4. In both Figures 5 and 6, the driving motor armature is designated 180, its series field winding 181 and its shunt field winding 182. v

- In Figurefi, compensating mechanism is employed forthe driving motor. The bulb 18? of the driving motor compensatin mechanism is illustratedas positioned in t e field winding 182. The. compensating resistance for-the driving motor is designated 183 and is arranged inseries with field winding 182. The contacts of compensating relays for resistance 183 are designated 18 185 and 186. The compensating mechanism acts, in the arrangement illustrated, to short-circuit steps of. compensating resistance 188 as the driving motor heats up; In this manner, the driving motor speed may be maintained constant, regardless of temperature variations in the motor. In such case the steps of compensating resistance 118 for the generator field winding may be made such as to compensate forchanges in resistance of the generator field windings and generator and elevator motor armature windings while the steps of compensating resistance 33 for the elevator motor field winding may be made such as to provide a uniform field for the elevator motor. 4

In Figure 6, compensating mechanism.- is provided for only the enerator and elevator motor. Thus, in suc arrangement, upon the driving motor becoming heated, its

speed increases due primarily to the increased resistance of its field winding 182 and consequent weakening of its field. Thus, the generator speed becomes higher and the generator voltage tends to increase. @wing to the fact that the generator field winding is not energized all the time due to numerous periods in vwhich the elevator car is at rest at the various landings, the compensa ing relay contacts N 188, O 189 and P 198 for generator field compensating resistance 118 may be arranged as breaking contacts to insert steps of resistance in circuit with the generator field winding as the temperature otthe generator increases. In this manner, the generator field is weakened so as to cause the generation of desired voltage for application to the elevator motor armature. In such case, the compensatin arrangement for the elevator motor would e the same as described for Figure 5.

In both Figures 2 and 6, arrangements are illustrated in which compensating mechanism for one of the drive units is omitted. Satisfactory operation may be obtained for certain installations by other arrangements. For example, in Figure 4, the compensating arrangements for both the generator field and elevator motor field may be omitted and the steps of compensating resistance 17 5 arranged so as to permit an increase in the value of exciter voltage as the temperature increase takes place. By proper choice of resistance steps 175, substantially uniform operation of the elevator motor may be obtained. This is due to the fact that as the resistance of the generator and elevator motor field windings increases, the exciter voltare compensating mechanism acts to provide v compensation regardless of the cause .of the temperature increases. Thus, any increase in room temperature sufficient to tend to vary the operation of the elevator motor is compensated for. Furthermore, the compeneating mechanism operates to provide the desired compensation in the case of short period's of shut-down in which the various drive units do not return to cold condition or in case the system is started. up under the conditions where the drive units areinot cold due to other causes, such as seasona'l provide the desired compensation in cases temperattires- Also, the individual compensating mechanism units may be. arranged to where the temperature changes in one or more of the drive units is difi'er'ent-from that of the others due to the location of these units in the penthouse or due to draugh s or other causes.

The principles of the invention are also applicable to other types of drive for the elevator car such as resistance controlled elevator motors, multi-voltage systems or any similar type of electric drive in which variation in operating conditions is likely to be obtained due to temperature chan es. The temperature compensating mechanism unit is only diagrammatically illustrated for the reason that it is desired to illustrate only the principles of the invention inasmuch as the construction or" the compensating aparatus may be considerably varied. Various expansible fluids maybe employed or other temperature sensitive devices may be used. The mechanism to which the temperature changes "are relayed to control the compensating resistance also may be varied. A single compensating mechanism unit may be employed for more than one unit ofv the system. The positions ofthe bulbs may be varied'. Other compensating resistance arrangements may be employed such as parallel resistancces or combination series and parallel resistances. Also, the compensating resistances ma be arranged in parallel with the windin s in conjunction with series resistance. n fact, any form of mechanism which compensates for changes in resistance of windings of an electric drive unit or units in accordance with temperature changes to which such winding or windings are subjected may be em loyed without departing from the spirit 0? the invention.

lhe compensation for temperature changes in accordance with the principles of the invention may be'very efiectively employed in conjunction with other compensating arrangements, such as those for compensating for variation in loads on the elevator motor.

A generator series field winding has been illust-rated as means for effecting load compensation. Uther arrangements may be employed, however, either in lieu of or in con unction with the series field winding.

In the control system illustrated, the starting and stopping of the car is effected by operation of a car switch to on and oil position. The control system illustrated is chosen merely for convenience of description and it is to be understood that the .principles of the invention are also applicable to other elevator systems, such as those in which push button control is employed to cause both the starting and stopping of the car or for causing only the stop ing of the car, or to those in which the starting of the car is under the control of an operator while the slow down and stopping is automatic. In systems in which the slow down and stopping of the car at the various landings is automatic, the dropping out of the accelerating switches may be controlled in accordance with the position of the car. In such event, no compensating mechanism would be employed for timing the dropping out of the accelerating switches. In case some of the accelerating switches are not controlled in accordance with car position in the slow down and stopping operation, the compensatin mechanism may be employed to control t e timing of these particular switches in dropping out if desired.

As many changes could be made in the above construction and many apparently widely different embodiments of th1s invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed. is:

1. In, combination, an elevator car, a source of electrical power, mechanism for transforming the electrical power from said source into mechanical power for raising and lowering said car, said mechanism comprising a dynamo-electric machine, aresistance for controlling the operation of said machine, and means responsive to the temperature of a winding of said machine for so varying said resistance as to cause uniform operation of the elevator car.

2. In combination, an elevator car, a'hoisting motor therefor having a field winding, a source of current for said winding, means for controlling the supply of current from said source to said winding, and means respons1ve to temperature changes of said WlIldlIlg for so controlling said first-named means asto maintain uniform current flow through said winding.

3. In combination, an elevator car, a source of electrical power, mechanism for transforming the electrical power from said source into mechanical power for raising and lowering said car, said mechanism comprising a dynamo-electric machine, a winding for controlling the operation of said machine, and

means for causing uniform operation of said car, said last-named means comprising means responsive to diiierent temperatures of said winding for compensating for changes in the value of the resistance of said winding incident to said difierent temperatures.

4. In combination, an elevator car, a source of electrical power, mechanism for transforming the electrical power from said source into mechanical power for raising and lowerin said car, said mechanism comprising a ynamo-ele'ctric machine having a winding, a resistance for controlling thev menace amount of currentsupplied to saidwinding, means for causing uniform o crating conditions of said car regardless 0 variations in the value of the resistance of said winding incident to temperature changes of said winding, said means comprising means responsive to the temperature of said Winding for varying said resistance.

5. In combination, an elevator car, a hoisting motor therefor, a separately excited field winding for said motor, a source or current for said field winding, a resistance electrically connected to said field winding, and means operable in response to the temperature changes in said field winding to vary said resistance in such a manner as to cause the same amount of current to be supplied to said winding from said source during each operation or said motor at a certain speed, regardless of any tendency of. said current to vaiy due to temperature changes. 1

6. n combination, an elevator car, a hoisting motor therefor, a separately excited iield winding for said motor, asource of current for said field winding, resistance connected to said winding, and means operable in response to temperature changes insaid winding to vary said resistance at a rate dependent upon the rate of change in value of the resistance of said winding incident to the flow and discontinuation of the fiow of current therethrough to maintain a uniform flow of current through said field windin 7. In combination, an elevator car, a hoisting motor therefor, a separately excited field winding for said motor, a source of current for said motor, a resistance in circuit with said field winding, relays for varying said resistance and means responsive to diderent' temperatures of said field winding for causing operation of said relays to vary said resistance in such manner as to provide uniform operation of the elevator car.

8. In combination, an elevator car, driving mechanism for said car, said mechanism comprisinga dynamo-electric machine having a winding, a resistance for controlling the amount of currentto said winding, means for varying said resistance, and temperature controlled means for causing the variation of said resistance by said resistance varying means to be such as to compensate for variations in the value of the resistance of said winding incident to changes in temperature of said winding.

9. in combination, an elevator car, a hoisting motor therefor, a generator for supplying current to said motor, means for driving said generator, a separately excited field winding for said motor, a separately excited field winding for said generator, a source of current for each of said field windings, and means for causing uniform operation of the elevator car, regardless of variations in the value of the resistance of the windings of said generator and. motor incident to temperature changes thereof, said means comprising r sistance connected to each of said field windings and temperature controlled means for varying said resistances.

10. In" combination, an elevator car, a

plying current to said motor, means for drivmg said generator, separately excited field windings for said motor and enerator, a source-of current for each of said field windings, a resistance in circuit with said motor field winding, a resistance incircuit with said generator field winding, and means responsive to the temperature of each of said field windings for varying said resistance for that winding to compensate for the changes in the value of the resistance of such winding incident to temperature changes thereof.

ll. In combination, an elevator car, a hoisting motor therefor, a generator, for supplying current to said motor, means for driving said generator, a separately excited field winding for said motor, a separately excited field winding for said generator, 9. source of current for each of said field windings, a resistance in circuit with said motor field winding, a resistance in circuit with said genera tor field winding, and means responsive to the temperature of said field windings for varying said resistances in such manner as hoisting motor therefor, a generator for supcause the amount oi? current supplied to said i motor field winding and the voltage applied to said motor by said generator for each operation oi the elevator car at full speed to be such as to provide uniform o eration of the elevator car, irrespective of t e temperature changes to which the windings of said generator and motor are subjected.

12. In combination an elevator car, a switching mechanism 'for controlling the operation of said car, said switching mechanism having a Winding, and means responsive to temperature changes of said winding for controlling the operation of said switching mechanism.

13. In combination, an elevator car, a hoisting motor therefor, switching mechanism for controlling the accelerationv of said motor, and means responsive to temperature changes afiecting the operation of said motor for controlling the operation of said switching mechanism in such manner as to compensate for such efi'ect of said temperature changes.

14 In combination, an elevator car, a hoisting motor therefor, switching mechanism for controlling the acceleration and retardation of said motor, and temperature responsive means for controlling the operation of said switching mechanism in such manner as to i provide uniform acceleration and retardation of said motor, regardless of temperature changes afiecting acceleration and retardation.

15. In combination, an elevator car, a hoist Ill ing motor therefor, a plurality of electromagnetic switches for controlling acceleration and retardation of said motor, each of said switches having an actuating coil, circuits for said coils, means for varying the impedance of said circuits, and means responsive to temperature changes affecting the operation of said motor for varying said impedance.

16. In combination, an elevator car, a hoisting motor therefor, a plurality of electromagnetic switches for controlling acceleration and retardation of said motor, and means responsive to temperature changes afiecting the operation of said motor for varying the timing of said switches.

17. In combination, an elevator car, a hoisting motor therefor, a generator for supplyin current to said motor, means for driving sai generator, a separately excited field winding for said generator, a source of current for said field winding, switching mechanism for varying. the amountof current supplied to said winding from said source, and temperature controlled means for controlling the timing of said switching mechanism.

18. In combination, an elevator car, a hoisting motor therefor, a winding for said motor, a source of current for said winding, means for controlling the supply of current to said winding from said source, means responsive to different temperatures of said winding for so controlling said first-named means as to compensate for variations in the value of the resistance in said Winding incident to temperature changes thereof, means for efi'ecting a change of speed of said hoisting motor, a winding for said last-named means, a source of current for said last-named winding, means for controlling the supply of current to said last-named winding from said last named source, and means responsive to different temperatures of said last-named winding for so controlling said means for controlling the supply of current to said last-named winding as to compensate for variations in the value of the resistance in said last-named winding incident to variations in the tern perature thereof.

19. In combination, an elevator car, a hoisting motor therefor, said motor having a field winding, an exciter for supplying current to said winding, means for driving said exc'iter, and means responsive to different temperatures of said excite'r controlling the value of the voltage generated thereby for application to said winding. V

20. In combination, an elevator car, a hoisting motor therefor, said motor having a field winding, an exciter for supplying current to said winding, means for driving said exciter, and means responsive to temperature changes affecting said exciter and said field windin for causing the current su plied to said field winding by said exciter to he maintained uniform, regardless of the efiect of said tempera= newness ture changes on the value of the voltage of said exciter and on the resistance of said.

winding. 9

21. In combination, an elevator car, a hoisting motor therefor, a generator for supplying current to said motor, a separately excited field winding for said motor, a separately excited field winding for said generator, an exciter for supplying current to said field windings, means for driving said exciter, and

means responsive to the temperature changes affecting the operation of said motor for controlling the value of the voltage generated by said exciter for application to said field windings.

22. ln'combination, an elevator car, a hoisting motor therefor, a generator for supplying current to said motor, a separately excited field winding for said motor, a separately excited field winding ,for said a generator, an

exciter for supplying'current to said field windings, means for driving said exciter and said generator, a resistance in circuit with said motor field winding, a.re s 1s tance in'circuit with said generator field winding, and means responsive to temperature'changes aiiectin the value of the excitervoltage, the value 0 generator voltage and the value of the field strength of the motor for causing the current supplied to said field windings by said exeiter to be of such value as-to cause uniform field strength of said motor and uniform cur-. rent conditions of the motor armature,-- rerality of elevator cars having substantially the same periods of operation and operating for substantially the same length of time during such periods, a hoisting motor for each car, a winding for each motor for controlling the operation thereof, and means responsive to temperature changesof said winding for one of said motors for controlling the flow of current in all of saidpwindings in such manner as to compensate for temperature changes affecting the operation of said motors.

In testimony whereof, I have signed my name to thisspecifieation.

EUGENE winson YEARSLEY.

ire