US2151734A - System of control for electric elevators - Google Patents

Description

March 28, 1939.

E. M. `BOUTON ET AL SYSTEM OF C ONTROL FOR ELECTRIC ELEVATORS Filed' Dec. 25, 1957 2 Sheets-Sheet l March 2s, 1939. E, M. BOUTON ET AL 2,151,734

SYSTEM OF CONTROL FOR ELECTRIC ELEVATORS Filed Dec. 23, 1937 2 Sheets-Sheet 2 D U M PHP/fra 5F; 5MB/f5 T v w xv Dl ISI/l -Ml l I/II/I/eF/I i i I i i I I D2 UZ MZ ZMaII I VIWrZI I I I I I I I I I I I I I I I I I I VI/V\ I I I IIIWI -wl I II I I I8 4 |555 I I WV/ i I I x/ I I I I I I I I gfx? I I I I l wz I I I I I I I 2 I I I I I I I U I I I I I I I Iv I I I I I I I I I I U M ;/D v `M4 p/ I I I I 5F4| Q/ I I I WV/ I Et L5 :En I I Q PZ I I I y I I SP3 2M? I I W/ P3 I o I :/l/ Q93 J3 II V3 n o I if Mc? W I BF2 e/ ow.;

W4 D4 U4 X WITNESSES: M3 INVI/VTORS o/af acq/ /Mh/f//Q/n5 /Q/.Doan//Ogaan/ /l/ (l/Www IQIVKJ/J.. 8%

A conditioning relay M is provided for connecting and preparing certain control circuits for operation when the car is to be started and for disconnecting them when the car is to be stopped.

A rst resistance relay V, a second resistance relay W and a third resistance relay X are provided for disconnecting the resistors rl to r9 in the rotor circuit of the hoisting motor when it starts and for reconnecting them in that circuit at a desired point in decelerating the motor.

A limiting relay 'I' is provided for bringing the resistance relays into effective operation and for disconnecting them from operation during certain operations of the car.

Heretofore Where single speed alternating current motors have been used for operating elevators, it has been difficult to secure a flexible system for controlling the speeds of the car as desired. In order to secure a flexible system which will permit the use of a motor of this character for operating an elevator car and at the same time be able to start and stop often without overheating the motor and secure different speeds of the car at different times, We have provided a control brake, such as an eddy current brake B, for applying a braking effect to the car when it is being decelerated and for also holding it at certain predetermined speeds, 'when desired, a regulating generator R for controlling the energization of the brake B, and a speed generator for controlling the regulator in accordance With the speed of the car.

The eddy current brake B is provided with a rotor 30 and two field windings, the iirst winding being indicated as BF4 and the second winding as BFS. The rotor may be either a solid iron type or a squirrel cage type, as required, to secure the torque desired and, as illustrated, is mounted di rectly on the shaft I6 upon which the hoisting motor H is mounted. The winding BF4 passes around the pole pieces 3| and 33 and is excited by a source of electric energy represented by the supply conductors L+5 and L-5. This Winding is provided to furnish part of the excitation necessary to secure the braking torque desired. A resistor rII) is disposed in circuit with the eld winding BF4 so that the value of the excitation of the winding BF4 may be adjusted. The winding BFS is disposed upon the pole pieces 32 and 34 and is connected to be energized by a small regulating generator R. Depending upon the voltage of the regulator, the eifect of the iield winding BFS when energized will be to either buck or boost the excitation of the field winding BF4 and thereby regulate the amount of braking torque applied by the brake B.

The regulator Ris driven at a contant speed by a three phase alternating current motor 4I and it is provided with a constant field winding RFI, a control field winding RF! and a series eld winding RFB. The motor 4| may be of any suitable three-phase alternating current type and is shown as having an armature 42 and field windings 43, 44 and 45 which may be connected by the contact members MI, M2 and M3 to a suitable source of electrical energy as represented by the supply conductors LI, L2 and L3. The regulator winding RFI is connected across the supply conductors L+4 and L-4 in order to secure a constant current supply of electrical energy for that winding. The accumulative series field winding RFE is disposed in series with the armature 35 to enhance the regulating effect of the regulator and should be or such a value that the current through it produced by the voltage of the regulator armature will produce just this amount of voltage in the armature. This series field may be weaker than the value just described in which case more effort will be required from the regulator fields RFI and RF2 to produce the desired speed and the effect will be that the speed regulation at this regulated speed will not be quite as good. If desired, it is practical to omit the series field entirely, but better results will be obtained if it is used. The field winding BF2 is connected for energization by the small direct current speed measuring generator S directly connected to the elevator motor shaft.

A resistor r|2 and a reactance coil 4B are disposed in circuit with the field winding RFI to secure a desired value of current in that field winding and to limit it 4to a value which will maire for smooth operation of the regulator. The two field windings RFI and RFZ on the regulating generator are normally set to balance each other when the brake B is in operation and the car is operating at the predetermined speed for which the system has been designed or adjusted.

The speed measuring generator S is connected to the shaft I6 and thus is operated by the motor H in accordance with the speed of the car. Its field winding SF3 is connected across the supply conductors L+4 and L-4 in order to secure a constant current supply of electrical energy for its field. Therefore its armature will supply electric energy to the eld winding BF2 of the regulator R directly in accordance with the speed of the elevator, thus exciting the regulator winding RF2 in accordance with the speed of the car. Hence, it will be apparent that the output of the regulating generator, as varied by the excitation of its eld winding BF2, Will control the brake energy of the eddy current brake B to decelerate the car to, and hold it at, a predetermined stopping speed.

A resistor ril is disposed in circuit with the field winding RFI of the regulator to control the regulator toA control the eddy current brake to cause the car to run at predetermined speeds. The intermediate speeds and low speed of the car will depend upon the amount of the resistance rl I inserted in the regulator field winding. In the present instance, we have shown two values of resistance, one to secure a predetermined intermediate speed and the other to secure a predetermined low speed, the low resistance to operate the car at an intermediate speed assumed to be approximately 130 feet per minute and the higher resistance to operate the car at a low speed of approximately 30 feet per minute. Which value of resistance is used will be dependent upon the position of the car switch. Other intermediate values may be provided by tapping off the resistance at different points and connecting such points to additional contacts oi the car switch.

A plurality of gate and door contact members 41 and 48 are disposed in Acircuit with the coils of the direction switches U and D and the condi tioning relay M to prevent operation oil the hoisting motor while the car gate or any one of the hatchway doors (not shown) is open.

The following is an assumed operation of the apparatus indicated in the drawings. It will be assumed that this apparatus is designed for operating an apartment house elevator or other elevator in which the normal high speed is approximately 300 feet per minute and that it is desired to have the car decelerate from the speed of 300 feet per minute to a low or stopping speed of approximately 30 feet per minute at which point the hoisting motor may be deenergized and Ythe stopping brake appliedito stop the car and hold it at the floor. It will also be assumed that it may be desirable at times to cause the car t'o run at an intermediate speed of approximately feet per minute.

It will be assumed now that the attendant on the car moves the car switch CS from its center or oiT position to its up high speed position toy L+4, sa, so, U, M, 41. n, L-l

The energization o1 the conditioning relay M closes its contact members Mi to M0. inclusive. The closing of the contact members MI, M2 and M3 connects the constant speed motor Il to the supply conductors LI, L2 and L3, thus starting that motor to operate the regulator amature 30 at a constant speed. The closing ot the lcontact members M5 energizes the ileld winding RFI of the regulator and the closing oi the contact memhers M6 energizes the field winding SP3 of the speed generator S. The closing of the contact members MH energizes the field winding BFl of the eddy current brake B. The closingl of the contact members M1 also energizes the brake coil i8 of the stopping brake i1,.thereby releasing that brake to permit the car to be operated by the hoisting motor H.,

The connections made by the conditioning 1elay M have. prepared the control system for op eration and the closing oi the contact members Ui and U2 ot the energised up direction switch U energiaes the iieid windings 2i, 22 and 23 ot the hoisting motor H and causes that motor to start the car unworthy. The closing oi the contact members U3 and Ut also connects the' held da ing Ritt ot the reeuioting generator to the arma ture t@ of the speed generator for operation in accordance with the upward movement of the cat.

However, it wiii be noted that the eddy ourm rent brake is not in operation at this time be cause the fuli "on position of the car switch CS connects the switch contact members il and te, thereby energising the regulator iiclci control re=I iay i@ through circuit The energized relay l1 opens its contact members Pt and does-ehn preventing enertion ot the eddy current heid windings EF@ and 3B.

Therefore, the eddy current breite is not now in reinos "t7, W to ont out the resistors et to t0 sited acceleration ot the hoisting motor The closing ci? the contact coctel; the relay V by the circtlt The resistance teinte are time' delay relays and, therefore, the relay V operates siowiy to close its contact members Vl and V2 thus shorting out the resistors r1, rl and rl to increase the speed of the motor H. I'he relay V also closes its self-l holding contact members V3 and closes its con.

tact members V4 to energize the second resistance relay. W by the circuit L+5, V4, W, Ti, Ml, L--I When the delay for the relay W expires, it closes its contact members Wi and'W2 thereby-short circuiting the resistors r4, T5 and r6 to eliminate them from thel rotor circuit of the hoisting motor H to increase its speed. The energized relay W also closes its self-holding contact members Wl and closes its .contact members W4 to energine the third resistance relay X which, upon expiration ofits time delay, closes its contact members Xi and X2 thereby short circuiting the resistors ri, r2 and r3 so that the hoisting motor H now runs at its full speed to operate the car at, say. 300 feet per minute.

The movement of the car switch to its up high speed position also closed the contact members 5I and 53 thereby short circuiting,r part of the resistance rt out of the circuit of the regulator field winding Riti so that, if the eddy current brake were being used, it would be regulated to control the speed of the car to approximately 130 feet per minute. However, the eddy current brake is not used while the car is at high speed and the value of this resistance at present has no effect.

It will be assumed now that the car after being operated for several floors, not shown, at the aumed speed of 300 feet per minute, is to be stopped by the car attendant at the next oor. In doing this, he will, when the car is about ilve feet from the ioor, move the car switch from the notch or contact 52 to the notch 5l to decelerate the car to an intermediate speed of approximately 130 feet per minute when it arrives at a distance ot" about two feet from the door. When the car is two feet from the door, he willi move the car switch down to the notch or contact member t@ to deceierate the car down to itslanding speed of approximately d@ feet per minute when it arrives at a distance oi', say, two inches from the door. When the car is at this two inch position troni the iioor,

the attendant `will center the car switch in order to deenergize the hoisting motor and applythe stopping brake to stop the car level with the floor.

In ioiiowing the alcove-mentioned operation, it Willi be eeen that' the tnovetnent'of the car switch trom-its high sneed position to the second notch position represented by the contact member tt leaves the contact members @t and $3 closed ont opens the contact members and to. The contact members dt and, 58 remaining closed sintetica the shoot circuit o ocation ot resistor rfl, thereby incre the recuiotor incid Wi cause the eddy current tot enengiaotion, to ttc intermediate The cocon Bt G3 deener ceiny if?, contact r -v connect the coerce ci suo/pty and connect the heid windings; to the armatnse ot' "ogg certero tor R .for the of bringing the sur.. rent braise t3 into operation to lower the speed of the ty te@ eet ontoct meno to constant a the strength o? .K

The closing of the contact members PI also causes the limit relay T to be energized when the field winding BF comes up to iull strength and the energized relay T then opens its contact members TI thus deenergizing, the resistance control relays V, W and X which, in turn, open their contact members VI, V2, WI, W2, XI and X2 to reinsert the resistors rl to rs in the circuit ot the armature 20 of the hoisting motor. The insertion of these resistors in the hoisting motor circuit and the energization of the brake B willcause the car to decelerate to a speed of approximately feet per minute by the time it arrives at a distance of about two feet from the iloor. By reason of various factors, the car may run at a greater or at a less speed, but if it does,V the eddy current brake will bring it into line with the desired speed.

This is effected because the insertion of lthe resistance into the rotor circuit causes the altern nating current motor to have a drooping speed characteristic with load. We can assume that at zero speed the motor will develop a little more than full load torque and at some intermediate speed such as 130 feet per minute in the car the motor will develop full load torque. If the load on the motor is less than full load the motor will run faster until at zero load it will run at its synchronous speed. It we assume half load in the car, the motor will attempt to run at a speed of, assume, 225 feet per minute, and to obtain a speed of 130 feet per minute, it is necessary to bring the motor load up to full load. This extra load is developed by the eddy current brake.

Under the condition of full load in the car, the load alone is sufficient to bring the speed down to 130 feet per minute and no torque is required from the eddy current brake. Under these con-l ditions coils BFl and BFS are energized equally and oppose each other and the net effect is that no ilux exists in the eld structure to set up a braking action. If any flux were present and some braking did occur the motor would be loaded to greater than full load and it would tend to run at a speed less than 130 feet per minute, and the voltage of generator S would be low, the excitation of field RF2 would be low, andiield RFI would predominate. The effect of this is to cause a change in' the current fiovving in the self-excited circuit (BB-RFB--PZ- BFL-36) in a direction to strengthen iield BFE and to increase the sell-excitation through field RFB. The increased excitation in field .BFS op poses the ux which is causing the braking, thereby reducing the braking effect. When the braking of the eddy current brake is reduced, the motor speed is then determined by the load in the car which being full load causes the car to run at 130 feet per minute.

The conditions just described are limiting ones, and we prefer to always have some braking eifort required from the brake under any cpneratn ing condition so that there will be some excess torque available to cause an increase in speed if such is necessary. This condition can be obtained by inserting a little less resistance in each of the resistors connected to the collector rings of the alternating current motor.

If the load inthe car is less than full load, for example, assume half load, then .the car tends to speed up to, say, 225 feet per minute. Under this condition, the voltage oi generator armature 40 will increase and field RFI will predominate over RFI and a voltage will be set notch 5| down to the notch 5a.

4and the flux in the brake set up by eld BF! will be so great that the brake sets up a half load drag on the motor. When this is added to the vhalf load in the car, the load on the motor is equal to full load and its speed settles to 130 feet per minute. At this speed, fields RFI and BF2 again oppose each other and no extra exvcitation occurs in regulator R and the armature 3G self excites ileld RFii to just maintain the current flowing to reduce the energiaation ci field BM to a point 'Where iieid BFI can produce haii load braking.

Assuming that we have now reached that point in the operation where the car is running at 130 feet per minute, where it is two feet from the floor at which the stop is to be made and where the attendant moves the car switch from the This operation opens the contact members 5I and 53 on the car switch, thereby reinserting the full amount of the resistor rl i in the circuit of the regulator held Winding RFI, which reduces its constant current energization to the lower predetermined value designed to cause the brake B to decelerate the car to aflanding speed of approximately 30 feet per minute when it arrives at a distance of about two inches from the floor. Inasmuch as the current value in the field Winding RFI has been reduced and the speed generator S is still operating in accordance with the speed ci the car, the amount of current supplied by the arm-- ature of the speed generator to the regulator field Winding BF2 is relatively greater than the value of the current in the regulator field Winding RFI. This causes the regulator armature 36 to alter its delivery of current to the brake winding BFS to produce braking torque as previously described. This braking torque causes the brake B to exert a strong retarding eifect on the car. As the car decelerates in response to the retarding effect of the brake, it, oi course, decreases the speed of the speed generator S which decreases its armature output to the regulator Winding BF2.

In addition, as the speed oi the hoisting motor falls, the torque output ci the motor increases, and, at some point, a balance will occur which, in this particular case, is designed 'to occur when the car is running at a speed of approximately A30 feet per minute.

When the car arrives at the speed of 30 feet per minute, it will continue to run at that speed ii the car switch is not moved, because. if it goes above that speed, it will increase the speed of the generator Si which will cause the regulator R to increase the retarding effect of the brake B; and if it goes below that speed, the corresponding decrease in speed of the speed generator S will rem duce the retarding effect of the brake B so that the car will pull back up to the desired landing speed of 30 feet per minute. In fact, the operation of the eddy current brake, the regulating generator and the speed generator will be similar to that described when they brought the car to, 75

and held it at, the intermediate speed of approximately 130 feet per minute.

However, the-car attendant centers the car switch when the car is two inches from the floor l members 53 and 50 thus deenergizing the up direction switch U and the conditioning relay M. The deenergization of the up direction switch opens its contact members Ui and U2 thus stopping the hoisting motor H and the deenergized relay M opens its contact members M1 thereby applying the stopping brake i1 to stop and hold the car level with the landing at which the stop is made. 'Ihe deenergized relay M also opens its contact members MI, M2, M3, M6, M5 and M6 to deenergize and stop the constant speed motor 4I i'rom operating the regulator R, to deenergize the regulator eld winding RFI, to deenergize the speed generator field winding SP3, to deenergize the eddy current brake winding BFI and the limit relay T thereby deenergizing the eddy current brake and restoring the control system `for its next cycle of operation in starting the car.

It should be understood that the normal high running speed oi' 300 feet per minute, the intermediate speed of 130 feet per minute and the landing speed of 30 feet per minute are gurative and have been assumed merely for purposes of illustrating the operation of our system. It will be apparent that any elevator engineer will be able to determine the speeds he desires in any installation and that, after these'speeds are assumed, heY can then readily determine the sizes of the various pieces oi' apparatus' such as the hoisting motor, the stopping brake, the ed current brake, the regulating generator` and its driving motor. and the speed generator. It will also be understood that the sizes and values will vary in each installation and that the engineer will have to design the sizes of the neld windings. etc., for such apparatus in accordance with the limits oi' the system being installed as usual in customary practice and in accordance with the principles disclosed in this invention.

By reason of the foregoing assumed operation, it is seen that we have provided a control ysystem for using a constant speed alternating current motor to drive an elevator car at various speeds and that the system will bring the car to, and

hold it at, predetermined speeds corresponding to the contact members or notches on the master switch employed for operating the car. In view of the fact that this system permits the use of a wound rotor motor ior the elevator, it will be round that the car may be started and stopped more often than with other alternating 'current multi-speed systems without overheating the motor. The reason for this is that the heat which would otherwise be generated in the motor is expended in the external resistors.

Although we have' illustrated and described only one speciiic embodiment oi our invention, it is to be understood that changes therein and modifications thereof may be made without departing from. the spirit and scope oi' the invention.

We claim as our invention:

1. In an elevator system for operating a car in a hatehway, a motor for operating the car, means for connecting the motor to a source oi. energy, an eddy current brake for the car, means for connecting said brake to a source of energy to cause it to apply a braking effect to the car, and means responsive to the speed of the car for controlling the braking eiect applied by the brake to the car.

2. In an elevator system for operating a car in a hatchway, a motor for operating the car, means for connecting the motor to a source of energy, an eddy current brake, means for connecting said brake to a source of energy to cause it to apply a braking eiect to the car, a speed generator, means for operating the speed generator at a speed proportional to the speed of the car, and means for causing the output of the generator to control the braking effect of the eddy current brake on the car.

3. In an elevator system for operating a car in a hatchway, a hoisting motor for moving the car, an eddy current brake for controlling the speed of the car, a regulating generator for controlling the eddy current brake, a speed generator for controlling the regulating generator, and

means for driving the speed generator in accordance with the speed of the car. f

4. In an elevator system for operating a car in a hatchway, a motor i'or operating the car, means for connecting the motor to a source of energy, an eddy current brake provided with a plurality of windings, means for connecting one of said windings to a constant current source of energy when the brake is to be energized for a braking operation of the car, and means responsive to the speed of the car for energizing another one of said brake windings in accordance with the speed of the car for controlling the braking eiectoi' the brake.

5. In an elevator system for operating a car in a 'hatchway. a hoisting motor for moving the car, an eddy current brake for controlling the speed of the car, a regulating generator for supplying energizing energy to the brake, a motor for driving the regulating generator at a constant speed, a speed generator connected to operate in accordance with the speed of the car, and means responsiveto operation of the speed generator for controlling the amount of energy supplied by the regulating generator to the brake for causing the brake to control the speed of the car.

6. Inan elevator system for operating la car in a hatchway, a hoisting motor for moving the car, an eddy currentbrake for controlling the speed ofthe car, a regulating generator for supplying energy to the brake, a' motor for driving the .regulating generator at a constant speed, a

speed generator' connected to operate in accordance with the speed of the car, means responsive to operation of the speed generator for-controlling the amount of energy supplied by the vregulating generator to the brake for causing the brake to control the speed of the car, and switch means for setting the regulating generator char-v acteristics to cause it, when controlled by the speed generator, to control the speed oi the car.

at the predetermined spend for which the switching means 'is set.

7. In an elevator system for operating the car in a hatchway, a hoisting motor for moving the car, an eddy current brake for controlling the l speed oi the car, a regulating generator for supplying energizing energy to the brake, said reguiator generator having a constant field Winding and a control ileld winding, a motor for driving the regulating generator at a constant speed, a

speed generator connected to operate in accord'- ance with the speed of the car, means for yconnecting the output of the speed generator to the control field winding of the regulator for controlling the amount of energy supplied by the regulating generator to the brake for causing the brake to control the speed of the car, a switching means for controlling the constant field winding of the regulator to cause the regulator, when controlled by the speed generator output, to so control the eddy current brake as to maintain the car at the predetermined speed for which the switching means is set.

8. In an elevator system for operating a car in the hatchway, a hoisting motor for moving the car, an eddy current brake for controlling the speed of the car, a regulating generator for supplying energizing energy to the brake, said regulating generator having a series field winding for controlling its regulating characteristics, a motor for driving the regulating generator at a constant speed, a speed generator connected to operate in accordance with the speed of the car, and means responsive to operation of the speed generator for controlling the amount of energy supplied by the regulating generator to the brake for causing the brake to control the speed of the car.

9. In an elevator system for operating a car in a hatchway, a motor, means for connecting the motor to a source of electric energy to operate the car, an eddy current brake for applying a braking effect to the car, said brake having a plurality oi' windings, means for connecting one of said brake windings to a constant current source of energy, a regulating generator having a plurality oi' windings, means for operating the regulating generator at a constant speed, means for conducting the output of energy from the regulating generator to another one of said brake windings whereby the braking effect of the brake on the car will be controlled by the regulating generator, a speed generator provided with a field winding, means for operating the speed generator in accordance with the speed ofv the car, means for connecting the speed generator field winding to a constant current source of energy, and means for conducting the output of energy from the speed generator to the regulating generator for controlling the energy supplied by the regulating generator to the brake at a value proportional to the speed or the car.

l0. In an elevator system for operating a car in a hatchway, a motor, means for connecting the motor to a source of electric energy to operm ate the car, an eddy current brake for applying a braking effect to the car, said brake having a plurality of windings, means for connecting one of said brake windings to a constant current Asource of energy, 9. regulating generator having a plurality of iield windings including a series eld winding for enhancing its regulating effect, means for operating the regulating generator. at a constant speed, means i'or conducting the output of energy from the regulating generator to one of said brake windings to cause the nraking eiIect of the brake on the car to be controlled by the regulating generator, a speed generator provided with a field winding, means for operating the speed generator in accordance with the speed of the car, means for connecting the speed genm erator field winding to a constant current source of energy, and means for conducting the` output oi.' energy from the speed generator to the regulating generator for controlling the energy supplied by the regulating generator to the brake for controlling the speed of the car to a predetermined speed.

11. In an elevator system for operating a car in a hatchway, a motor for driving the car, an eddy current brake for applying a braking eiiect to the car, said brake having a first winding and a second winding, means for connecting said first Winding to a constant current source of energy, a regulating generator for energizing the said second Winding, said regulating generator having a constant winding and a control winding, means for driving the regulating generator at a constant speed, a speed generator having a ield winding connected to a constant current source of energy, means responsive to operation of the car for driving the speed generator in accordance with the speed of the car, and means for connecting the output of the speed generator to the control winding of the regulating generator to cause the regulating generator to control the energization of the eddy current brake to bring the car `to a predetermined speed.

12. In an elevator system for operating a car in a hatchway, a motor for driving the car, an eddy current brake for applying a braking effect to the car, said brake having a first winding and a second Winding, means for connecting said first winding to a constant current source of energy, a regulating generator for energizing the said second Winding, said regulating generator having a constant winding and a control winding,

means for driving the regulating generator at a constant speed, a speed generator having a field winding connected to a constant current source of energy, means responsive to operation of the car for driving the `speed generator in accord ance with the speed of the car, means for connesting the output ci the speed generator to the control Winding of the regulating generator whereby the energy supplied by the regulating generator to the eddy current brake will be controlled in proportion to the speed of the car, a resistor associated with the constant winding oi the regulating generator, and a switch for including more or less oi the resistor in circuit with that iield Winding in accordance with the predetermined speed to which the car .is to be controlled.

i3. In an elevator system for operating a. car in a hatchway, a motor for driving the car, an eddy current brake for applying a braking effect to control the .sp-eed of the car, said brake having a :First winding and a second winding, means for connecting said first winding to a constant current source oi energy, a regulating generator ior supplying electric energy to said second Winding, said regulating generator having a constant Winding and a control winding, means for con necting said constant winding to a constant cur rent source of energy in a constant direction, means for driving the regulating generator at a constant speed, a speed generator having a ileld 'Winding connected to a constant current source of energy, means for driving the speed generator in accordance with the speed oi the car, and means for connecting the output energy of the speed generator to the control `winding oi' the regulating generator in a direction opposite to the direction of energy in Said constant winding, to that the output of the regulating generator will control the energization of the eddy current brake to hold the car to a predetermined speed.

14. In an elevator system for operating a car in a hatchway, a hoisting motor for moving the car, an eddy current brake for controlling the speed of the car, a regulating generator for controlling the brake, a speed generator responsive to operation of the car for controlling the regulating generator, a switch, means responsive to one position of the switch for connecting the hoisting motor, the brake, the regulating generator and the speed generator to sources of electric energy for starting them in operation, means responsive to another position oi the switch for disconnecting the brake from its sources oi energy but maintaining the motor, the regulating generator and the speed generator connected to trolling the brake, a speed generator responsive to operation oi' the car for controlling the regulating generator, a switch, means responsive to one position of the switch for connecting the motor, the brake, the regulating generator, and the speed generator to theirlsources of energy for starting them in operation, means responsive to another position of the switch for controlling the output of the regulating generator to reduce the braking eiiect of the brake, means responsive to another position of the switch for disconnecting the brake from its source of power tov render it ineffective to apply a braking effect to the car, and means responsive to another position of the switch for disconnecting the motor, the brake, the regulating generator and the speed generator from their sources oi' energy.

16. In an elevator system for operating a car in a hatchway, a hoisting motor for moving the car, a control brake for controlling the speed of the car, a stopping brake for stopping the car, a regulating generator for controlling the control brake, a motor for operating the regulating generator. a speed generator for controlling the regulating generator, means for operating the speed generator in accordance with the speed of the car, a switching means, and means responsive to operation of the switching means for connect-` ing the hoisting motor, the control brake, the regulating generator,'the generator motor-.and

the speed generator to sources of electric energyand rendering the stopping brake inedective in one position of the switching means, for controlling the output of the regulating generator to reduce the braking effect of the control brake in another position of the switching means, for rendering the stopping brake ineffective and disconnecting the control brake from its sources of power but maintaining the hoisting motor, the electro-magnetic brake, the regulating generator, the generator motor, and the speed generator connected to their sources of power in another position oi' the switching means, and for disconnecting the hoisting motor, the control brake, the regulating generator, the generator motor and the speed generator from their sources of electric speed generator in accordance with the speed of the car, a switching means; and means responsive to operation of the switching means for connecting the hoisting motor, the said rst winding and said second winding of the brake, the constant field winding of the regulating generator, the generator motor and the ileld winding of the speed generator to their sources of electric energy in one position of the switching means, for disconnecting said rst winding and said second winding of the brake from their sources 4of electrical energy but maintaining said constant iield winding, oi' the regulating generator, the generator motor, the field winding of the speed generator, and the hoisting motor connected to their sources of energy in another position of the switching means, and for disconnecting the eddy currentbrake, the hoisting motor, the generator motor, the regulating generator and the speed generator from their sources of energy in the oi! position of the switchingmeans..

18. In an elevator system for operating a car in a hatchway,'a hoisting motor for the car, an

eddy current brake for the car, said brake having a ilrst winding and a second winding, a regulating generator for supplying electric energyl to said second winding, said regulating generator having a constant eld winding and a control neld winding, a resistor connected to the constant field winding, .a motor for driving the regulating generator at a constant speed, a" speed generator having a field winding, means for driving the speed generator in accordance with the speed oi the "car, a switching means; and means responsive to operation of the switching means for connecting vthe hoisting motor, the said first winding and said second winding of the brake, the constant field winding of the regulating generator, the generator motor and the eld winding of the speed generator to sources of electric energy in' vone position of the switching means, for varying l maintaining the constant` ileld winding, the generator motor, the eld winding of the speed generator, and the hoisting motor connected to their sources of energy in another position 'of the switching means, and for disconnecting the eddy current brake, the hoisting motor, the generator motor, thev regulating generator and the speed generator from their sources ot energy in the on positionA of the switching means.

19. In 'an' elevator system for operating a car in a hatchway, a motor, means for connecting the vmotor to a' source of electric energy to operate thev car, an eddy current brake i'or applyingy a.

braking eiiect to the car, said brake having a Iplurality of windings, means for connecting one of said brake windings to a constant current source of energy, a regulating generator having f a plurality of windings, a motor connected to means for operating the speed generator in accordance with the speed of thecar and in accordance with the direction of the car, means for connecting the generator field winding to a constant current source of energy in a constant direction, means for conducting the output of energy from the speed generator to the regulating generator for controlling the energy supplied by the regulating generator to the brake at a value proportional to the speed of the car, a switch for controlling the operation of the car, and means responsive to operation of the switch in reversing the direction o! the car for reversing the direction of the output oi' the speed generator.

20, In an elevator system for operating a car in a hatchway, a hoisting motor for the car, an eddy current brake for applying 9. braking effect l to the car, said brake having a iirst winding and a second winding, means for connecting the said first. winding to a constant current source of energy in a constant direction, a regulating generator having a constant winding and a control winding, means for operating the regulating gen erator at a constant speed. means for conducting the output of energy from the regulating generator to the second winding o1' the brake to energlze it whereby the braking effect of the brake on the car will be controlled by the regulating generator, a speed generator provided with a field winding, means for operating the speed generator in accordance with the speed of the car, means for connecting the speed generator field winding to a constant source of energy, and means for conducting the output of energy from the speed generator to the control winding of the regulating generator to energize it in a. direction opposite to the direction of energization of the constant eld winding of the regulating generator so that the energy supplied by the regulating gcnerator to the brake will be controlled by the operation of the speed generator.

Images