US1581457A - Motor-controlling apparatus - Google Patents

Description

A ril 20, 1926.

MOTOR CONTROLLING APPARATUS 2 Sheets-Sheet 1 Filed July 27, 1920 April 20, 1925. 1,581,457

D. L. LINDQUIST ET AL MOTOR CONTROLLING APPARATUS Filed July 27, 1920 2 Sheets-Sheet 2 S M 1 INVENTOR BY $34M ATTORNE S ma a A r. 20, 1926.

UNITED STATES PATENT orrica.

DAVID L. LINDQUIS'I, OE HARTSDALE, AND DAVID, C. LARSON, OF YOE'KERS, NEW

YORK, ASSIGNORS TO OTIS ELEVATOR COMPANY, 01 JERSEY CITY, NEW JERSEY, A.

CORPORATION OF NEW JERSEY.

moron-CONTROLLING APPARATUS.

Application filed July 27, .1920. Serial No. 399,379.

To all whom it may concern:

Be it known that we, DAVID L. LIND- QUIST, a subject of the King of Sweden, residing in Hartsdale, county of Westchester, State of New York, and DAVID C. LARSON, a citizen of the United States, resident of Yonkers, in the county of Vestchester and State of New York, have invented new and useful Improvements in Motor-Controlling Apparatus, of which the following is a specification.

My invention relates to motor controlling apparatus, particularly that used for traction elevators or frictional driving appara-. tus, althOugh it may have a general application. 1

The objects of my invention are thepro- .vision of improved and eflicient apparatus for controlling electric motors on a multivolt system. The specific objects of'the invention will appear hereinafter, the novel combinations of elements being set forth in the appended claims. The objects of my improvement are First: To provide means for changing the time constant on electric "switches operated by solenoids.

Second: To provi method of connecting the armature of a motor to a higher or lower voltage.

Third To bring the armature of a motor to zero speed or practically so, by connecting stopping resistances across said armature without interrupting its circuit.

The aforesaid objective results are particularly valuable in the application of motors to elevators or hoisting apparatus.

I attain these objects by the electric controlling apparatus illustrated in the accompanying drawings, in which, Figure 1 is a diagrammatic illustration of the entire machine; Figures 2, 3, 4, 5 and 6 are detailed diagrams of how the armature is connected from a lower to a higher voltage or vice versa.

Similar numerals refer to similar parts throughout the several illustrations.

In order that my invention'may be understood thoroughly. I will'now proceed to describe the same in the following specification referring to the accompanying drawings and will pointout the novel features thereof in appended claims.

de a simple and effective slate, on which are mounted the following electrically operated switches: 1 potential switch marked A, 1 up reversing switch marked B, 1 down reversing switch marked C, 3 speed switches marked D, E, F, 1 fast speed switch marked G.

The switches A, B, C, D, E and F are all alike and specially designed to operate their contacts in the following rotation. lVhen the magnet coilis energized and actuates its plunger, the contact in the upper right hand corner closes first, then the lower right hand contact opens, next the upper left hand contact closes and finally the lower left handcontact opens. lVhen the circuit for the magnet coil is interrupted and the plunger drops back, the lower left hand contacts will engage first again, then the upper left hand contacts break, next the lower right hand contacts engage again and finally the upper right hand contacts separate. The contacts are so arranged, that one contact must be made before the next can break and that contact must be broken before thenext contact can be made, etc. In general the magnets operating the swit'ches are made larger than would be necessary to operate the contacts. This is done to obtain a time constant in releasing. The time constant is the maximum for the reversing switches B and C and will be approximately one second in this case. -The first speed switch D has an approximate time constant of three quarters of a second. The second speed switch E has an approximate time constant of three eight-11s to one half a second. The potential switch A and third spec-(l switch F will have no time constant. The various time constants are obtained by the use of the following methods:

Using oversize magnets and varying: 1 the magnet parallel resistance, 2 the air gap between the cores when closed, 3 the excitation on the magnet. 4 the load on the magnet.

The operation of the various magnet switches is as follows:

Potential switch A.

The potential switch is -arranged with a separate secondary, in the form of a copper sleeve around the core to give an easy operation when opening and closing. In order to I eliminate the time constant, every heavy Kid brass se arating washer is used between the cores. he otential switch is connected across the mzuns, a and e, and is only opened incase of emergency, such as failure of the machine to respond to the car switch Y or overspeed. The potential switch mounts the auxiliary makin contacts, 23 and 24, which are used to breali: one side of the lorake circuit to give additional protection against grounds.

Reversing switches B and U.

I The reversing switches are first connected between the mains c and b, but across the armature alter the first speed switch D has pulled in. The excitation of themagnet coil on the reversing switches will therefore depend on the voltage across the armature. They are arranged with an internal secondary in the term oi. a copper sleeve around the core and an external variable secondary in the form of resistances 62 and 72 connected in parallel with the magnet coils. in parallel with the magnet coil on switch 38 is the resistance l2 and on switch C the re sistance 19d. Either one of the reversing switches is called upon to perform the fol lowing operation in regard to time of drop ping out When the car switch is brought to center osition ste by step, the third, second an first spec switches will, when dropping out, reduce the voltage across the magnet coil and consequently the excitation. The auxiliarycontacts ll9-and on the first speedswitch D insert the resistance 62 in series with the magnet coil, thereby still reducing the excitation of the same. When the car switch is centered, the reversing switch will drop almost immediately, due to. the fact that not only the excitation has been reduced, but the parallel resistance has been increasedhy the amount of the resistance 62,. the latter now being in series with the parallel resistance. When the car switch is hrought quickly to center or reverse, the reversing switch must hold in aye" roximately one second, but it should drop rig t after the first speed switch, The large time constant is obtained because the magnet was across the highest voltage, consequently brought up to high excitation helorc interrupting the circuit. The dropping out of the reversing switch right after the first speed switch 1D is obtained. by having this speed switch insert additional resistance in parallel with I the reversing switch coil, which already has heen referred to, v I

The nest operation called for is, when the car switch is .hrcneht "partl to centerand then quickly all the way to center position or reverse. in this case, as lee-fore, the re-= yersing switch will hold in until alter the first speed switch has dropped out and then drop out.

The last operation is o oening the reversing switch by the automatic stopping switch S, In this case, the contacts on the automatic stopping switch disconnect the coil entirely from the parallel resistances and the magnet'will releaseat once.

First speed switch 0.

The first speed switch is connected across the armature and is'arranged with two sec ondaries, one in the form. of-a copper sleeve around the magnet core and the other in the form of the permanent parallel resistance 201 across the coil to obtain a large time constant. The automatic regulations of the time constant is done by regulating the excitation of the magnet. The time constant, when the car switch is brought quickly to center, will be approximately three quarters to half a second and when the car switch is brought slowly to center, approximately one half of this amount. The variation in excitation is obtained by the auxiliary contacts and 186 on the-third speed switch F, which contacts short circuit the resistance 1% in series with the magnet coil on the first speed switch. The switch D has a time constant both in opening and closin Second speed sw tch The second speed switch E is connected in series with the first speed switch B, when the first speed switch has operated and opened its auxiliary contact 118., The time constant of this switch is governed the same as the first speed switch, hut is adjusted to approximately one halt the time of the first speed switch. The switch E has a time constant hoth in'opening and closing.

Third-speed switch F.

The third speed switch F is arranged with no time constant at all The time constant opening is eliminated by using a larger air gap and brass washers between the cores.

llel'erring to l i urc l besides the before named switches, ll designates the brake, l the armature; lit the reactancc coils; L limit switches in the hatchway; ill the governor switch; N is the safety switch in the car: 1 a safety device under the car; S the automatic stopping switch which is mounted on top of the car and operated by cams, mounted on top and bottom of hatchway; i: designates the car switch in the car; 5, 6, 7,8 are ances, S. F. R, so that whenever there is potential between the mains a and e, a circuit can be traced from the positive main a through the conductor 25, shunt field windings, conductor 183, resistance S. F'."R., conductors 189 and 40 to the negative main 6. The shunt field will therefore be permanently excited, but its strength will vary according to the amount of the resistances. F, R. and the potential across the mains. The shunt field corresponding to full car speed is left on permanently for the sake of safety, and also to prevent too sudden acceleration with heavy load on dowrr motion of the car or light load on the up motion. Connected across the shunt field is the high resistance P. F. It, to take up the shunt field discharge in the event that the shunt field circuit should be interrupted.

Whenever there -is proper potential between the mains a and e, the solenoid of the potential switch will become energized and actuate its plunger. Then the contacts and 16 will engage and the auxiliary contacts 23 and 24 practically at the same time, next the contacts 17 and 18 separate, and the contacts 19 and 20 engage and finally the contacts 21 and 22 separate. The engagement of the contacts 15 and 16 and 19 and 20 respectively connect the first voltage step a and b to'the reversing switches, while the separation of the contacts 17 and 18 and 21 and 22 disconnect the stopping resistances 7 and 8 from across the armature I. When the auxiliary contacts 23 and 24 engage, one side of the brake circuit is made. The circuit for the solenoid of potential switch A may be traced from the positive main a through conductors 25 and '26, fuse 27 conductors 28 and 29, blade 30 of switch N, conductor 31, safety switch P, conductor 32, limit L conductor 33, limit L conductor 34, contact on governor M, conductor 36, magnet coil on switch A, conductor 37, limit "L conductor 38, limit L, conductors 39 and 40 to the negative main 6.

After the potential switch A has operated, the entire machine is. ready foroperation in either .up or down direction, depending upon the operation of the car switch Y. The latter is mounted in the car and can of course be of any type. The one demonstrated on Figure 1 is merely used for demonstration purposes. This car switch has a handle or lever 49 which is pivoted in the center 50 and provided with a contact se 'ment 51 which will connect, when the handle 1s brought down as far as possible in the direction indicated by the arrow marked up, the spring pressed contacts 45, 46, 47 and 48, and when brought down in the direction of the arrow-marked down, connects the contacts 41, 42, 43 and 44 together,

I shall actuate the handle 49 in three steps so as to make clear the different operations controlled by the car switch. When the lever 49 receives as much actuation in the up direction soas 'to connect with the contact segment 51, the contacts 45 and 46, theselenoid of the up reversing switch B will be put across the first voltage step a and Z) and when energized operates its plunger. The circuit for the B switch solenoid can be traced from the positive main a through the conductors 25 and 26, fuse 27, conductors 28 and 29, blade 52 of switch N, conductor 53, auxiliary contact 54 on the bottom of reversing switch C, conductor 55, contact 45, segment 51, contact 46 in car switch Y, conductor 56, contact 57 on stopping switch S conductor 58, magnet coil of switch B, conductors 59, 60 and 61, resistance 62, conductors 63, 64 and 65, fuse 66, conductors 67 and 68, contacts 112 and 113, conductor 70, contacts 117 and 116 on bottom of first speed switch D, blowout coil 71 to the negative main 6. Parallel with the coil for the B' switch and the contact 57 of the automatic stopping switch S in series with it, is the resistance 72, which is connected by conducnect one side of the armature I to the positive main a and also completes the circuit for the brake magnet H which will become energized and release the brake. At the same time the auxiliary contact 109 on the bottom of switch 13 will be opened, which breaks the circuit for the solenoid on the down reversing switch C, and makes -it impossible for the latter to receive current and to operate, while the up reversing switch B is operated. The brake circuit may be traced from the positive main a through the contacts 15 and 16 on potential switch A, conductors 74 and 7 5, contacts 101 and 102, conductors 78 and 79, stopping resistance 6, conductor 80, switch 81 on top of the brake, conductor 82, solenoid on brake H, conductor 83, auxiliary contacts 24 and 23 on potential switch A, conductors 84 and 40, to the negative main a. When the brake solenoid receives current and actuates its plunger, the latter opens the switch 81 on top of the brake as it arrives at its limit of travel, and inserts the resistance 85 in series witlrthe brake solenoid, so as to reduce the current consumed and to prevent excessive heating.

After the contacts 101 and 102 on switch 13 are engaged, the actuation of the plunger causes the contacts 103 and 104 to become separated, which disconnects the stopping resistance 6 from one side of the armature 5, on one side of the armature ll.

I. After the contacts 103 and 104: have been separated, the-contacts 105 and 106 become engaged and connect the other side of the armature l to the negative maiu'b. The

tacts 107 and 108 will be separated and open. the circuit of the stopping resistance The armature circuit may be traced from the positive main a through contacts 15 and 16 on potential switch A, conductors 1 1 and 75, contacts 101 and 102, on switch B, conductor 78, contacts 139 and 1 10 on switch C, conductors 86 and 87, reactance coils K, conductor 38, armature l, conductors 39 and 90, contacts 114 and 113 on switch O, conductor 91, contacts 105 and 105 on switch B, (1011* doctor 92, contacts 20 and 19 on switch A, blowout 941, conductor 03, contacts 112 and 113 on switch D, conductor 70, contacts 117 and 115, on switch D, blowout 11 to the negative main 5.,

The motor is running at slowest speed as more plainly shown on Figure and will continue to do so until the lever 19 on car switch Y receives additional actua-= tion to cause the segment 51 to connect the contacts 15 and all together, which will cause the solenoid on the hrst speed switch D to become energized fhe circuit of first speed switch D may be traced from the positive main 0; through conductors 25 and 26, fuse 27, conductors 28 and 29, blade 52 on switch N, conductor 53, auxiliary contact 5 1 on switch C, conductor 55, contact 45, seg-- ment 51 to contact 4:? in car switch Y, condoctor 95, contact 96 on the stopping switch S, conductors 97 and 98, solenoid on switch D, conductors 99 and 100, auxiliary contact 118 on the bottom o1 switch D, conductor 208, resistance 209, conductor'14l5, resistance 1 16, conductors 161 and 152, stopping resistance 5, conductors 14'? and 91, contacts 143 and 144 on switch C to the negative side of the armature l,

Parallel with the magnet coil on switch D is the resistance 201 which is connected by the conductors 200 and 202 to the junction points on conductors 98 and 39 respectively. The parallel resistance 201 serves to obtain a large time constant when releasing the switch D as described before, The re sistance 209 which is in series with the contact 118 on the bottom ct? switch D will cause a portion of the current to pass throu h the conductor 159 which is connected at the junction point on conductor 99, the magnet coil on switch E, conductor 160, to the junction point on conductor 1151 The current passing through the coil ed switch E is not sufiicien-t howeverto operate that switch.

The energization of. the magnet coil on switch D will cause its p'lun er to close first the contacts and 111 wh1chconnects the resistance 9'across the mains 5 and '0, as shown in Figure 3. That circuit may be traced from the main 0 through blowout coil 156, contacts 127 and 128 on switch E,

conductor 155, contacts 124 and 123.011

switch E, conductor 154C, blowout coil 153, conductors 152 and 151, contacts 110 and 111 on switch D, conductor 150, resistance 0, conductor 69, contacts 112 and 113 on switch D, conductor 70, contacts 117 and 116 on switch D, blowout coil 71, to main 5). At the same time the auxiliary contacts 119 and 120 on switch D will engage and short circuit the resistance 62 which is in series that the conductor 69, which comes from the minus side of the armature l is connected on the junction pointyoi the resistances- 9 and 10, which are oi the same ohmic re sistance, consequently the armature receives half the voltage between 5 and c more and increases in speed. The armature circuit now may be traced from the conductor 69, through resistance 9, conductor 150, con tacts 111 and 110, on switch D, conductors 151 and 152, blowout coil 153, conductor 15%, contacts 123 and 124 on switch E, conductor 155, contacts 127 and 128 on switch E, blowout coil 156 to the negative main 0.

After the contacts 112 and 113 on switch D have separated, the contacts 114: and 115 on switch D'engage and short circuit the resistance 9 by means of the conductor 15'? which comes from the junction point on conductor 68, as shown in Figure 5. The armature l is now directly connected to the scc ond voltage step a and c and will thus speed up to a predetermined second speed. Finally the contacts 116 and 117 on switch D separate and disconnect the armature from the first voltage step a and 5, as shown in Figure 6. At the same time the auxiliary contact 118 on switch D opens and puts the solenoid of switch E in series with the, solenoid of switch D, by rneansot the conductors 159 and 160 which are tapped ed at the junction points on conductors 99 and 100 and respectively.

As the solenoid on switch E becomes ener gi'zed and operates its plungenit will engage the contacts 121 and 122 on switch E,

and connect the resistance 11 across the mains c and (Z. This circuit may be traced froin the main (Z through blowout 163, con tacts 135 and 136 on switch F, conductor 164, contacts 132 and 131 on switch F, conductor 165, blowout coil 166, conductors 167 and 168, contacts 121 and on switch E, conductor 169, resistance 1i, conductor 158, contacts 123 and 124 on switch E, conductor 155, contacts 127 and 128 on switch E, blowout 156 to main 0.

After the contacts 121 and 122 on switch E are made the contacts 123 and 124 on that switch separate and insert the resistance 12,

which is equal to the resistance 11 in series with the latter. As can be seen on the drawing, the conductor 158, which comes from the armature is connected on the junction point of the two resistances consequently the armature will receive half the voltage of c-d more and thus increase in speed. After the contacts 123 and 124 have been separated, the contacts 125 and 126 on switch E engage and short circuit the resistance 11, by connecting the conductor 154- through conductor 170, the contacts 125 and 126 and conductor 167, etc., directly to the main (1. It will be seen, however, that the resistance 12 ,is now only temporarily connected across the mains 0-07, because immediately after the contacts 125 and 126 are engaged, the contacts 127 and 128 separate and disconnect the main 0 from the resistance 12 or any other circuit.

The armature circuit may now be traced from the positive main a through contacts 15 and 16 on switch A, conductors 74 and 7 5, contacts 101 and 102 on switch B, conductor 7 8, contacts 139 and 140 on switch G, conductors 86 and 87 reactance coils K, conductor 88, armature I, conductors 89 and 90, contacts 144 and 143 on switch 0, conductor .91,

92 "coil 94, conductors 68 and 157, contacts and 114 on switch D, conductor 152, blowout f t n. The coil on "switch F. however,

contacts 106 and 105 on switch B, conductor contacts 20 and 19 on switch A, blowout coil 153, conductors 154' and 170', contacts 126 and on switch E, conductor 167, blowout coil 166, conductor 165, contacts 131. and 132 on switch F, conductor .164, contacts 136 and -onrswitch F, blowout coil 163 to main d. The motor is now running at third speed. At the same time as the contacts 127 and 128 on switch E separate, the auxiliary contacts 205 and 206 on switch E engage an short circuit the resistance 203 by means of the conductors 204 and 207 which come from the junction points on the conductors 181 and 182 respectively. The resistance 203 is in series with the magnet coil on switchF to allow the latter to become slightly ;ener.- switch handle 49 should.-

gized-in case the car he brought to its extreme up or downposi- A traced from the positive main (2,

two resistances, will .will:

switch F is closed and when energized will The circuit may be operate its plunger.

through conductors 25 and 26, ruse 27, conductors 28 and '29, blade 52 on switch N, conductor 53, auxiliary contact 54 on switch G, conductor 55, contact 45, segment 51 to contact 48 in car switch Y, conductor 17 9, contact 180 on stopping switch S, conductors 181 and 204, auxiliary contacts 205 and 206 on switch E, conductors 207 and 182, solenoid on switch F, conductors 210 and 162, stopping resistance 5, conductors147 and 91, contacts143 and 144' on switch C, conductors 90 and 89 to the negative side of the armature I. First the contacts 129 and 130will en age an connect the resistance 13 across t e mains d and e. This circuit may bevtraced from the main 0?, through blowout coil 163, contacts '135 and 136 on switch F, conductor 164, contacts 132 and 131, conductors and 171, resistance 13, conductor 172, contacts 130 and 129, conductors 173 and 174, blowout coil to main e.

After the contacts 129 and 130 on switch F are engaged, the actuation of the plunger will cause the contacts 131 and 132 to become separated and consequently insert the re: sistance 14 in series with the resistance 13, The resistances 13 and 14 are of the same ohmic resistance, and the conductor 171 which comes from one side of the armature being connected on the junction point of the receive half of the voltage between the mains d and c more, so speed up to a predetermined amount of revolutions. The continuing of actuation of the plunger will next engage the contacts 133 and 134 on switch F which short circuit the resistance 13, by connecting the armature conductor 165 through the conductor 176, contacts'134 and 133 and conductor 174 and blowout 17 5 directly to the negative main 8. The resistance 14 is now tem 0- rarily connected across the mains d an e but immediately after the contacts 133 and v d 134' are engaged, the contacts" 135' and 136 on switch F will be separated and open the circuit of the resistance 14 and disconnect the main d. from any circuit. At the same time as the contacts 135 and 136 on switch F separate the auxiliary contacts and 186 on switch F will engage and short circuit the resistance146, .whiclr'is in series with the solenoid on switches D- an'd E, through conduct rs 184 and- 187 which'eome' scribed before.

from the junction points on conductors 145 and 161 respective y and thereby. increase the current in the solenoids on switches D and E. This is done for the purpose of releasing those switches instantly if such might be required. The armature circult may now be traced from the positivemain a, through the contacts 15 and 16 on sw tch A, conductors 74 and 75, contacts 101 and 102 on switch B, conductor 78, contacts 139 and 140 on switch C, conductors 86 and 87, reactance coils K, conductor 88, armature ll, conductors 89 and 90, contacts 1414: and 1 13 on switch C, conductor 91, contacts 106 and 105 on switch B, conductor 92, contacts 20.

and 19 on switch A, blowout coil .94, conductors 68 and 157, contacts 115 and 1,11 on switch D, conductor 152, blowout 0011 153, conductors 154 and 17 (1, contacts 126 and 125 on switch E, conductor 167, blowout coil 166, conductors 165 and 176, contacts 134 and 133 on switch it, conductor 17 4;, blowout coil 175 to negative main 6.

The motor is now running at fourth speed but will increase unto fifth or full speed, after the switch Ghas dropped open an separated its contacts 177 and 178, thereby nserting the resistance S. F. in series with the shunt field and weakening the latter.

. The solenoid of switch G is so connected between one side of the armature circuit and the main 6, that as soon as either one of the reversing switches ii and C operates the solenoid on switch G becomes energized and engages the contacts 177 and 178, thereby short circuiting the resistance S. F, R. and bringing the shunt field to its maximum strength, As that side of the armature is connected step by step towards the main e, those skilled in the art will readily see that the voltage across the solenoid of the switch G- becomes smaller until it finally becomes zero, that side of the armature being directly connected to the main 6, and causing the plunger of switch G to drop back with the result as de- The circuit of the solenoid on switch (1* may be traced from the corn ductor 89 on one side of the armature through the conductor 90, contacts 144: and 1 13 on switch C, conductors, 91 and 14:7, stopping resistance 5. conductor 162, solenoid on switch Gr, conductors 188, 189 and 10 to main 6.

The car and motor are now running at full speed and will continue to do so' until the car is brought to a stop by one of the many stopping devices. Should the speed however exceed a predetermined value, the governor M will engage its contacts 195 and 196 and short circuit a section of the resistance S. F. R. and thus strengthen the shunt field and reduce the speed of the motor. The governor in case of excessive speed of the elevator operates to close the contacts 195' and 196*to out out a secti n of. the shun field resistance and strengthen the shunt field of the motor in order thereby to reduce the excessive speed of the elevator, but does not in that operation open the contact 35 in the circuit to the magnet coil of the potential switch and thereby allow the latter to drop open; if, however, after the governor has closed the contacts 195 and 196, excessive speed of the elevator still obtains, the governor will thereupon open the contact 35 which will serve to deenergize the magnet coil of the potential switch and that'switch will then drop open and cutoff the current supply circuit to the armature of the motor,

and allow the elevator to slow down. The most common way of stopping the car is of course by bringing the lever 49 on the car switch Y to the center. done in two difi erent ways, gradually and suddenly, and for each occasion the time constant of the switches is different. Other ways of stopping the car are when the car reaches its top or bottom landing and the car switch is still held in its full-on position, then the car will be stopped by the automatic stopping switches, which contacts, corre spond to and are in series with the contactsinthe car switch Y. It will be seen that a quicker stop is required than in the case of the stopping at an intermediate floor by means of the car switch. A much quicker stop yet is required when the car its normal limits of travel and opens the limit switches L andfli on the top or L and If at the bottom of the hatchway, or when the operator in the car loses control over the apparatus and opens the safety switch N, or when the car exceeds its'normal speed and the governor M opens the contact 35, in each case interrupting the circuit of the potential switch A, thereby disconnecting the motor from the line.

First 1 will describe the method mostly used for stopping the car, by bringing the lever 49 on the car switch Y to the center, step by step. ll/hen the car and motor are runnlng at full speed and the car switch lever 49 is moved one space towards the center, so that the segment 51 breaks the flow of current to the contact 4-8, and consequently interrupts the circuit for the solenoid on the last speed switch F, that switch drops out immediately, having no retardation or time constant. lVhile its plunger is on its travel, the contacts 135 and 136 on switch ll, engage first and connect the resistance 11- across the mains (Z and e. That circuit may be traced from the main (Z, through blowout coil 163, contacts 135 and 136 on switchld, conductor 164:, resistance 14, conductors 171, 165 and 176, contacts 134-. and 133 on switch F, conductor 17st. blowout coil to the main '6. Practically at the same time as the contacts 136 and 135 engage, the auxiliary contacts 186 and separate and insert This however can be goes beyond again the resistance 146 in series with the solenoids on switches D and E reducing the current in those solenoids.

After the contacts 135 and 136 are engagedthe contacts 133 and 134-on switch F separate and insert the resistance 13 in series with the armature and in series with the resistance 14, the two resistances now being across the mains (Z and c with the armature conductor 171 in the junction point and center of the two'resistances. It can thus be seen that the armature is connected toa lower voltage and this is done without any jolt or 'jar to the car, the armature being under absolute control with the resistances 14 and 13, the armature current passing out through either of the resistances, depending upon the counter E. M. F

After the contacts 133 and 134 are separated the contacts 131 and 132 on switch F engage again, thereby short circuiting the ,resistance 14 and connecting the armature conductor directly to the main '42. Finally the contacts 129 and 130 separate and disconnect the armature entirely from the main e.

The armature is now connectedbet weenthe mains a and d and decreased in speed.

When the lever 49 on car switch Y is moved 7 switches D" and E are opened, but those two switches are so designed that the switch E will drop out before the switch D. When the switch E drops back the contacts 127 and 128 will engage first and connect the resistance 12 across the mains c and (1. After that the contacts 125 and 126 separate and insert the resistance 11 in series with the armature and the resistance 12 having the armature conductor 158 connected in t e center of the two resistances 12 and 11, conseguently the motor will decrease in speed bemg connected to a voltage half the potential between themains c and (5 lower as before.

' Next the contacts 123 and 124 onswitch E engage and short circuit the resistance 12 and connectin the armature directly to the main 0. Fine. ly the contacts 121 and 122 separate and open the circuit to the main d. Then the switch D will release and first engage the contacts 116 and 117 thereby connecting the resistance 10 across the mains b and 0. At the same time the auxiliary contact 118 on the bottom of switch D closes again and short circuits the solenoid on.

switch E, preventing it from operating in case of faulty connections or a ground. Next the contacts 114 and 115 separate an 4 insert the resistance 0 in series with the ar- .mature and the resistance 10, decreasing again the motor speed. Next the contact 112 and. 113.cngage and short circuit the resistance 10 and connect the 'aznature did the same rotation, v

lever 49 is brought to the center all at once,

'rectly to the main 6, thereby decreasing the motor speed. lVhen the last contacts 110 and 111 separate, the main 0 is disconnected to full strength and by doing so bringing the motor hacir to its first or slow speed.

When the car switch lever 49 is brought to the cent-er, the segment 51 breaks the connection between the contacts 46 and in the car switch and interrupts the circuit for 3 the solenoid on switch B. This switch however drops out slowly on account of the resistance 72, which is in parallel with the solenoid and takes up its discharge .First the contacts 107 and 108 on switch B, engage, which connects the stoppin'g resistance 5 in parallel with the armature, and next the contacts 105 and m switch B separate, which disconnects the armature, with the resistance 5 in parallel with it, from the line. Immediately after the cont-acts and 106 have separated, the resistance 5 will perform its function as a' stoppmg resistance, taking up the stopping current, generated by the still revolving armature. Next the contacts 103 and 104 on switch B engage and connect the stopping resistance 6 in parallel with resistance 5 and across the armature, thereby bringing the rotation of the armature of the motor practically to a stop. Finally the contacts 101 and 102 separate, disconnecting the other side of the armature from the line and also interrupting the brake circuit, causing the brake to drop back and bringing the motor and car to a stop. As the contacts 101 and 102 separate, the auxiliary contact 109 on the bottom of the switch B closes again and makes it possible to opcrate the opposite reversing switch C.

From the diagram, Figure 1, it can be start the motor rotating in the opposite direction as when the switch B is separated. The speed switches D, E, F, and G operate inthe cases of both switches B and O in Whenever the car switch the circuit for all the switches is interrupted practically at the same time, but they w ll drop back in the same succession as when.

the lever 49 is brought'back slowly. Th

- switch having one end of its winding connected to the winding of the accelerating only difference is that the motor will come to a quicker step; however, gradually and with out jolt orjar of the elevator.

Should the ear approach its top or lower landing, a cam mounted on the top and bottom of the hatchway will open first the contacts 180 and 192, next the contacts 96 and 191' and finally the contacts -57 and 190 on the automatic stopping switch S, interrupting the circuits of-the switches in the same succession as the segment 51, when the car switch lever 49 is brou ht to the center. The only difference is -t at the contact 5'? or 190 will not only interrupt the circuit to the solenoid on either switch B or C, but does that in such a manner that the discharge of these solenoids cannot be taken up by their respectively parallel resistances and thus causing those switches to drop out quicker and bringingthe car to a quicker Sto hould the car exceed its extreme limits of travel, a cam mounted in the car will engage the limits 1 and 3 which are mounted at the top of the hatchway, or limits 2' and 4- which are mounted on the bottom of the hatchway and open the circuit of the solenoid on the potential switch A and cause that switch to drop back immediately. JV hen the switch A drops back, it will first'engage its contacts 21 and 22 which connect the *stopping resistances 7 and 8, which are in series with each other, across the armature.-

Next the cont-acts 19 and-20-will separate and disconnect one side of the. armature from the line. The stopping resistances 7 and 8 will now slow down the armature and when the contacts 17 and 18 engage, the resistance 7 is short circuited by the conductor 193.

The low resistance 8 across the armature will bring the car practically to a' stop, when the brake, which circuit has been interrupted by separating the auxiliary contacts 23 and 24 on switch A, will be released and stop the motor entirely.

' What ll claim is:

' 1. in an electric elevator, the combination with the car and an electric hoisting'motor, of a plurality of current supply mains of unlike voltages, clectromagnetically operable reversing and speed switches adapted to pair the mains for unlike voltages and con nect the motor to them, an o crating switch for the car, the windings oi the reyersing switches beingadapted for connection by the cal-switch to a pair of the supply mains and the windings or the speed switches being adapted for connection by the carswitch across the motor armature an additional. elec-v tromagnetically operable switch for controlling the motor field strength, said last named menace switches and the motor armature and the other end. connected to one of the mains.

2. In an electric elevator, the combination with the car, a hoisting motor, a field for the motor and resistance for the field, a plurality of supply mains of unlike voltages, electromagnetically operable reversing and speed switches adapted to pair the mains for unlike voltages and connect the motor to to be connected by the car switch with a pair of the supply mains and across the motor armature, and the windings of the speed switches adapted to be connected by the car switch across the motor armature, and a fast speed switch for the motor having a pair of contacts adapted to place the resistance in circuit to the motor field for fast speed or the motor, and having a winding adapted to be connected to one side o't' motor armature and to one supply main whereby as the motor is connected from low voltage mains to higher voltage mains in accelerating the winding is being automatically connected from a source of high voltage to sources of lower voltage for its contacts to operate and place the resistance in circuit with the motor field for fast speed of the motor.

3. In combination, a switch having a winding,.a source of current for the wind- .th em,- an operating switch for the car, the 7 windings of the reversing switches adapted ing, a resistance connected in series with c said winding, a second resistance connected across said winding so as to delaythe operationot the switch for a certain period of time-upon the discontinuation of thesupply of current to the winding,-and vmeans for delaying the operation or said switch. for a longer period of time upon the discontinuation or the supply or current, said means and winding, and a contact on a speed switch adapted to short circuit said seriesresistance upon the operation of the speed switch whereby the operation of the direction switch in opening is delayed when said contact has been closed, and when said contact is open a quick opening of said direction switch is obtained due to the said resistances being in series with each'other across the winding or the direction switch.

7 In testimony whereof, we have signed our names to this specification.

DAVID L. Linnonisr. DAVID o. nausea.

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