US1767125A - Electric elevator system - Google Patents

Description

' June 24, 1930. s. B. GROSVENOR ELECTRIC ELEVATOR SYSTEM Filed Feb. 16, 1923 5 h tsh 1 June 24, 1930. e. B. GROSVENOR 1,767,125

ELECTRIC ELEVATOR SYSTEM Filed Feb. 16, 1925 3 Sheets-Sheet 2 4 W/T/VEJS kw (B b INVENTOR wwkfw 5 g" I fl;

June 24, 1930, G. B. GROSVENOR I ELECTRIC ELEVATOR SYSTEM Filed Feb. 16, 1923 3 Sheets-Sheet 5 .JTTURNEX Patented June 24, 1930 UNITED, STATES PATENT "OFFICE GRAHAM B. GBOSVENOR, OF CHICAGO, ILLINOIS, ASSIGNOR 1'0 OTIS ELEVATOR COM- PANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY ELECTRIC ELEVATOR SYSTEM Application alea February 1c, 1923. Serial No. 319,425.

proportion to the unbalanced load being lift ed'so that, in stopping, the effect of gravity 'is compensated for'by the kinetic energy in the moving parts. This means that the greater the unbalanced load being lifted, the faster the elevator will run. This is very important in making the actual stop from low s eed as it makes it possible todisconnect the elevator motor from its power supply at a fixed distance from the landing and make an accurate stop.

The'object of my present invention is to provide means to compensate'for the effect of gravity in stopping an elevator by causing the speed of the elevator to automatically be in some predetermined proportion to the unbalanced load being lifted, the means employed being applicable-to various methods of elevator control hitherto in use.

I accomplish this object by the use on the hoisting motor of a series field winding which is' connected in the armature circuit an embodiment of my invention in a system.-

only during such time as the elevator is being retarded, and in such a way that the flux, due to the series coils, is in the reverse sense to that produced by the separately excited field coils, these latter being always su pliedlwith current in one direction.

order that my invention may be fully understood, it will be described in connection with the accompanying drawings, in which I Figure 1 is a wiring diagram illustrating utilizing a single'voltage supply and rh'eo static control.

Figure 2 is a wiring diagram of a system in which a multivoltage power supply with a proper control panel .isused according to my invention.

Figure 3 illustrates my invention in connection with a variable voltage current supply as set forth in my copending appl ication Serial No. 541,815, patented December 22, 1925, No. 1,566,399. Referring more particularly to the draw- 1ngs:-

Figure 1 is a wiring diagram for an elevator semi-automatically controlled, utilizing a common form of rheost-atic control with modifications. Emergency devices and safety features have been omitted in the wiring diagrams associated: with-this case, as these appurtenances are too well known to require description and as in the normal operation of the equipment these devices serve no purpose in connection with the present invention.

To operate the elevator motor 2, a car switch 5 is provided in the elevator car and so wired that the car switch handleG must be moved to either extreme position to cause the elevator to start after which car switch handle 6 may be returned to neutral position at or near a landing previous to the one at which it is desired to stop. The automatic switches 7 and 8 will then automatically slow down and stop the elevator level with the desired landing.

The elevator motor 2 has a constantly energized field winding 10. Suitable resistance 15 may be provided to cause the strength of the field, due to winding 10, to be of a value that will give desired full speed. The field winding 10 and resistance 15 are preferably wound with conductors which will have a negligible temperature coeflicient so that no variation in field strength will occur with change in temperature during operation. As change in the field strength will materially change the speed, the field and other features of motor design are so designed that variation in temperature or load will not materially affect the speed. c

The object in having constant speed is for the purpose of fixing the rate of retardation and the distance from the landing necessary to initiate the slow-down to provide minis mum length of time for retardation, slow speed running and stopping.

Resistance 12 is protective resistance provided for field winding 10 in the event of its power supply beingrinterrupted.

. means for automatically bringi This will require but one slow-down switch 7 operating one slow-down contact for each direction of travel. In my copending application Serial No. 622,149 I have describled an e evator to rest under other con itions of floor hei ht or where the speed of the elevator is ifierent in one floor runs from its speed in two or more floor runs.

The sto at the lan ng, re uires one contact a so for each direction o travel to stop theelevator.

Consider the elevator to be moved in the direction to the next adjacent landing.v

u (Ear switch handle 6 is moved to the extreme left position so that contactor 16 covers contact finger points 17, 18 and 19. .A circuit is then, completed from feeder 13 through fuse 20, lines 21 and 22, up direction switch magnet coil 23, line 24, tenninals F -F of traveling cable 9, line 25, contacts26 and -27 of the terminal automatic stop switch, lines 28 and 29 contact finger 17, contactor 16, contact nger 19 lme 30, terminals .BB of travehng cable 9, line 31, bottom contacts 32 and 33 of the down direction switch, lines 34 and 35, fuse 36 to feeder 14.

The up direction switch then closes contacts 37 and 38, 39 and 40, 41 and 42, and 43 and 44. Contacts 45 and 46, and 47 and 48 are opened.

The brake magnet coil is ener 'zed by a circuit from feeder 13, throug line 49 contacts 38 and 37, line 50, contacts 41 and 42, line 51, brake magnet coil 3 .and rotective resistance 4, line 52 to feeder 14. he energizing of brake magnet coil 3 releases the brak v The armature of the elevator motor re: vceives power from line 13, through contacts 38 and 37, lines 53 and 54, armature winding of elevator motor 2, lines 55 and 56 contacts 39 and 40, line 57, contacts 58 and 59, lines 60 and 61, starting resistance 62 to feeder 14. Due to the fact that contacts 58 and 59 are in engagement and contacts 109 and 110 are separated, the series field winding 11 is not connected in the elevator motor armature circuit.

A by-pass'resistance 67 at this time is connected across elevator motor armature leads '66, resistance 67, line 68 ping switch 8, functionin only 54, through line 53, contacts 37 and 38, line 49, line 13, line 63, contacts 64 and 65, line line 61, line 60 contacts 59 and 58, line 57, contacts 40 and 39, line 56 to lead 55.

A circuit is also completed for the magnet coils of automatic slow-down and stoppin switches 7 and 8 from feeder 13, throug line 49, contacts 38 and '37, line 50, contacts '41 and 42, lines 51 and 69, fuse 70, line 71,-

terminals H-H of travelin cable 9, line 72, magnet coils 73 and 74 o the automatic slow-down and stoppin switches 7 and 8 respectively lines 75 an '76, terminals C--C of the travel fuse 36 to,feeder 14.

Immediately upon the up direction switch closing, the fast speed magnet coil is enerized and it closes its switch. The circuit is obtained from feeder 13 through line 49 ing cable 9, lines 77, 34 and 35,

contacts 38 and 37, line 50, contacts 41 and 42, line '51 to the right, fast speed magnet 0011 78, line 79, terminals A-A of the traveling cable 9, line 80, contacts 81 and 82 of the terminal stop switch, lines 83 and 84,

car switch contact finger 18, contactor 16 contact finger 19, line 30, terminals B-B of the traveling cable9 line 31, contacts 32 and 33 lines 34 and 35, fuse 36 to feeder 14. The fast speed switch then closes contacts 85 and 86,'which completes a circuit for acceleratingmagnet coil 88 from feeder 13, through fuse 20, line 21, contacts 85 and 86, line 87, accelerating magnet coil 88 to feeder 14'.

The accelerating magnet then closes contacts in pairs as follows :89 and 90, 91 and 92, 93 and 94, 95 and 96 and 97 and, 98 which serve to short-circuit starting resist-' anoe 62 in successive steps. Immediately upon the first section of resistance'62 being short-circuited by contacts 89 and 90, the bypass resistance 67 is open-circuited by the contacts 64 and 65 opening.

The'elevator will now run at full speed. A circuit is established through the compensating switch magnet coil 107 from feeder 13 through line 49, contacts 38 and 37, line 50, contacts 41 and 42, lines 51 and 69, fuse 70, line 71, terminals H-H of the traveling cable 9, lines 72 and 99, resistance 100, line 101, terminals E'E of the traveling cable 9, line 102, contacts'44 and 43, line 103, contacts 104 and 105, line 106, compen sating switch magnetcoil 107, lines 108, 34 and 35, fuse 36 to feeder 14. The last step of the accelerating magnet opens contacts 104 and 105 hrs this circuit after full acceleration. The value of the resistance is such, however, that magnet 107 was not sufliciently energized to close the contacts that series field winding 11 is still not connected in circuit.

It was shown that when contactor 16 of the car switch bridged the contact fingers 17, 18 and 19, the elevator was brought up to full speed. By centering the car switch handle 6, contactor 16 uncovers fingers 17, 18 and 19. Contact fingers 19 and 17 and 19 and 18 are still bridged by resistances which enable the direction and fast speed switches respectively to remain closed after the air gaps of the cores have been reduced by the closing of the switches. The circuit, bridging contact fingers 19 and 17 to hold in the u direction switch, extends from contact nger 19 through lines 111 and 115, contacts 116 and 117 on the automatic stopping switch, resistance 118, lines 28 and 29 to contact finger 17. For the fast speed switch, the circuit is obtained from car switch finger 19 through line 111, contacts 112 and 113 on the automatic slow-down switch, resistance 114, lines 83 and 84 to contact finger 18.

The elevator proceeds to a point approximately midway between landings where the magnet core of slow-down switch 7 is attracted by the stationary armature 119, which is mounted in the hatchway, opening contacts 112 and 113, thus releasing the fast speed switch by deenergizing magnet coil 78 and opening fast speed contacts85 and 86.

The opening of contacts 85 and 86 deenergizes the accelerating magnet 88 which inserts resistance 62 in series with the elevator motor' armature, resistance 67 in parallel with the elevator motor armature and closes contacts 104 and 105.

Automatic slow-down switch 7 has also closed contacts 121 and" 122, which shortcircuit resistance 100 in series -with com- 'pensating switch magnet coil 107.' The compensating switch is, therefore, closed, closing contacts 109 and110 and opening contacts 58 and 59.

When theautomatic slow down switch is beyond the range of'armature 119, contacts 121 and 122 again'open but thecircuit remains established through resistance 100 and sufiicient current flows to keep compensating switch magnet coil 107 energized sufficiently to keep its switch closed.

By t e opening ofcontacts 58 and 59 and the closing of contacts 109 and 110, the armature current of the elevator motor is caused to flow through the's'eries field wind-v ing 11 which is; so connected as to be in opposition to the shunt field winding when the-motor 2 is drawing current from the line, but since, in slowing down, the elevator motor will deliver energy, the series winding 11 will increasethe field strength, thereby increasing the retarding action. When slow speed is reached, differential compounding will be obtained, the demand for power by the elevator motor will be determined by its load so that with increasin loads the speed will be increased and with decreasing loads the speed will be decreased. The extremes, of course, are full load up and down. In the first case, differential compounding will cause an increase of speed while in the second case the elevator motor will deliver power since it is being driven by gravity, thereby reversing the current in the series field winding which results in cumulative compounding. field' winding here is for the purpose of slowing down and compensating for gravity at slow speeds preparatory to stopping by causing the kinetic energy of the moving parts for various loads "to be inversely to the action of gravity. By properly proportioning the series winding and the shunt winding, a condition is reached that .will cause the elevator to stop in the same distance, regardless of load.

When the elevator nearly reaches the landing, the magnet core of switch 8 is opposite stationary armature 120 and is attracted by it, opening contacts 116 and 117, releasing the up direction switch which interrupts cur- The use of the series.

rent to the elevator motor armature, and applies the brake while the closing of bottom contacts on the up direction switch, connects dynamic stopping resistance 123 across the elevator motor armature leads 54 and 55, through line 127, contacts 47 and 48, resistance 123, contacts 124 and 125, and line 126.

Figure 2 is an adaptation of similar control as in Figure 1 for use on multi-voltage' system of supply mains where four sources of supply of electrical energy are furnished connected in series to permit four equal steps of voltage; for example a battery of storage cells providing a total E. M. F. of 240 volts with three intermediate and two external supply lines. These lines may be numbered 128, 129, 130, 131, 132 and so connected as to obtain 60 volts or any multiple of 60 volts with a maximum of 240 volts. The feeders are so arranged that 128 and 129 have a difference in potential of 60 volts, 128 and 130 have 120 volts, 128 and 131 have 180 volts and 128 and 132 a difference in potential of 240 volts. This system is not new and is well known in the art.

-The general arrangement of control from the up direction switch magnet coil circuit, which switch in turn com letes various supplementary circuits and en the circuit for the magnet coils of the speed or accelerating switches, which in turn perform their rebut is only connected in during slowing down and stopping. On starting up, contactor 133 of car switch 5 bridges contacts 134, 135 and 136 and a circuit is obtained throu h the up direction switch magnet coil as follows:- from feeder 128 through fuse 137, lines 138 and 139, up direction switch magnet coil 140, i

line 141, terminal stop switch contacts 142 and 143, lines 144 and 145, contact finger 134, contactor 133, contact finger 136, lines 152 and 151, contacts 153 and 154, lines 155 and up' 156, fuse 157, line 158 right to feeder 132.

When returning car switch handle to neutral contact fingers 134 and 136 are still bridged through line 152, right lines 151 and 150, contacts 149 and 148, line 147, re-' sistance 146, line 145 to contact finger 134.

The resistance 146 is of such value that the up direction switch will remain in afterbein closed.

e up direction switch closes contacts 159 and 160, 161 and 162, 163 and 164 and 165' and 166, and oge hns contacts 167 and 168 and 169 and 170.

e brake magnet coil is now energized from line 128 through line 171, contacts. 160 and 159, line 172, contacts 164 r and 163, line 173 left, brake magnet coil 3 and protective resistance 4, lines 175 and 158 to feeder 132. The brake is now lifted and the elevator will run on low speed with 60 Y volts available for the elevator motor armature from feeders 128 and 129 as follows from feeder 128 through line 171, contacts 160 and 159, line 176, armature-winding of elevator motor 2, lines 179 and 180, contacts 161 and 162, line 181, resistance 177, line 178, contacts 182 and 183, lines 184 and 185,

contacts 186 and 187, line 188, contacts 189 and 190 to feeder 129.

By-pass resistance 193'is also across the armature at this time from armature line 179 through lines 180, 191. and 192, resistance 193, line 194, contacts 195 and 196,

' lines 197 and 198 to armature line 176.,

Auxiliary fast speed switch then closes as its magnet coil 199 is energized through a,

1 The auxiliary-fast speed switch closes contacts 204 and 205,'short-circuiting armature series resistamTe 177 and opens contacts 195 and 196, disconnecting by-pass resistance 193. Contacts 206 an are closed preparatory to getting higher speed. The elevator motor is now running at low speed 'with60 volts across its armature terminals and "without series or by-pass resistance. Automatically, however, the elevator continuesup to full speed. The successive accelerating steps are obtained by the closing ofswitches by magnet coils 208, 209 and 210, a circuit forthese coils being obtained primarily from the car switch, and next by the closin of contacts 206 and 207 bythe auxiliary ast speed switch. Magnet coils 208, 209 and 210 are electrically interlocked by means of auxiliary contacts, for sequence in operation when closing their respectiveswitches, all receiving power from the same SOlllCB.

The energization for magnet coil 208 is obtained from feeder 128 through fuse 137, line 211, magnet .coil 208, line 212, contacts 207 and206, line 213 contacts 214 and 215v of the terminal stopping. switch, line 216, car switch contact finger 135, contactor 133, contact finger 136, lines 152 and 151, contacts 153 and 154, lin; 155 up, fuse 157, line 158 to feeder 132.

circuit extends from contact 136 through lines 152 and 151, contacts 220 and 219, line 218, resistance 217 to contact finger 135. The resistance 217 is of such a value that the switches operated by magnet coils 208, 209 and 210 will remain in after being closed, but they will not pull in if open.

The closing of the switchby the energizing of magnet coil208, raises the potential across the elevator motor armature from to 120 volts as follows :The contacts coning sequence. Contacts 221 and 222 close completing a circuit from feeder 129 throu h contacts 190 and 189, line 188, contacts 1 7 and 186', line 185, resitanee 232, line 231, contacts 222 and 221, line 225, contacts 226 and 227,, line 228, contacts 229 and 230, to feeder 130 connecting resistance 232 across 60 volts potential. Contacts 186 and 187 open, connecting resistance 233 in series with resistance 232, the line 184 instead of being connected direct to feeder 129 is now obtaining power from a point between resistances 232 and 233 connected in series across feeders 129 and 130. Contacts 223 and 224 then close-short-circuiting resistance 232. The line 184 feeding the armature circuit is new direct connected to feeder 130 of the 120 volt level and resistance 233 is goiiggcted directly across the feeders 129 an Contacts 189 and 190 then open which dis- With car switch handle in neutral, this trolled by this switch operate in the followconnects resist ance 233, and the armature of the elevator motor is then on the 120 volt level and the transfer resistances 232 and 233 are open-circuited.

Auxiliary contacts 234 and 235'and 236 and 237 on the switch controlled by magnet coil 208 are closed at this time. The closing of contacts 234 and 235 short- circuits contacts 201 and 202, controlled by the auxiliary fast speed retarding magnet coil 242, through lines 243, 156 and 203 and 442 and 200.

The purpose offthis arrangement is to' prevent auxiliary fast speed magnet coil 199 from being deenergized and thus effecting the insertion of series resistance 177 and 'by-pass'resistance 193 in the armature circuit at other than low speed preparatory to stopping. Magnet coil 242 0 the auxiliary fast speed retarding switch is connected across the armature terminals of the elevator motor 2 and so adjusted as to open contacts.

.201 and 202 at a voltage above 60 volts on an increasing voltage and to be of sufficient strength to hold the contacts open, because of the decreased air gap of the magnet cores, at 60 volts on a decreasing voltage.

Therefore, when accelerating, magnet coil 242 will not cause contacts 201 and 202 to open until after magnet coil 208 of the first accelerating switch has closed contacts 234 and 235. At such-time, the voltage at the armature terminals will be 120. Then when slowing down preparatory to stopping the release of the switches controlled by coil 208 .will open contacts 234 and 235 and since contacts 201 and 202 are open the auxiliary fast speed magnet coil 199 will be deenergized and its switch will be released to connect series resistance 17 7 andby-pass re- Contacts 236 and 237 are also closed by the energizing of the magnet coil 208 and a circuit is completed to cause the second step of acceleration by magnet coil 209 obtaining its'feed from wire 213 in the same manner as coil 208 but branching off at the control panel through line 244, contacts 237 and 236, line 245, coil 209, line 211, fuse 137 to feeder 128. The second step of acceleration brings the elevator armature voltage up to 180 increasing this voltage 60 volts inv the same manner as the switch controlled by magnet coil 208.

Auxiliary contacts 238 and 239, closed by the energizing of coil 209, complete the circuit for magnet coil 210 and the armature .voltage is increased another 60 volts in the same manner, at which time the armature of the elevator motor will'be across the two outside feeders 128 and 132 having a differswitch 7 passes its respective stationary armature 119. The circuits of the magnet coils of. both the automatic slow-down switch 7 and automatic stopping switch 8 are closed from feeder 128 through line 171,

contacts 160 and 159, line 172, contacts 164 and 163, lines 174 and 246, magnet coils 247 and 248, line 249, fuse 157, line 158 to feeder 132. The magnet core of the automatic slow-down switch 7 is attracted by the stationary armature and contacts 219 and 220 open, which causes the opening of all circuits for magnet coils 208, 209 and 210 which will release their switches bringing the elevator motor armature voltage down to 60 volts. These switches are mechanically interlocked or if desired may be electrically interlocked so that the releasing will be in the reverse sequence to that in which the switches were coil 208 releases the auxiliary fast speed switch by deenergizing magnet coil 199 and series and by-pass resistances 177 and 193 respectively are. connected in the armature circuit of the elevator motor 2.

At the timethat the slow-down switch 7 the low speed to be inversely to the load im posed on the elevator'motor. The circuit for compensating switch magnet coil 252 is from feeder 128 through. line 171, contacts 160 and 159, line 172, contacts 164 and 163, lines 174, 246 and 452, contacts 251 and 250, lines 253 and 254, contacts 166 and 165, lines 255 and 256, contacts 241 and 240, line 257, magnet coil 252, lines 258 and 156, fuse 157, line 158 to feeder 132. The deenergizing of magnet coil 252 causes contacts "260 and 261 to close and contacts 183 and 182 to 0 en. The

closing of contacts 260 and 261 s unts the tact 183. The opening of contacts 183 and 182 then interposed the series field winding in the line providin for the compounding desired. The series; eld winding is not provided with an adjustable shunt as it maybe so diesigned as to give the compounding de- SITE 1 I Not only can an extremely low avera armature o ened, releasing the up direction switch,

Thle elevator will now be running at slow s preparato to sto in T e otentiifi available fo r the ele ftorgarmatuig will be volts and the series field'winding 11 and series resistance 177 will be in series with the'armature windin By-pass resistance 193 will be across t e armature winding. speed be obtained-but the series field win ing will ermit higher speeds lifting the loads than that obtained when lowering the loads. The stopsing of, the elevator with this method of spec regulation at low speeds will be accomplished in a very short distance, lending itself to extreme accuracy of stopping at floor landings by automatic means.

When the elevator platform is nearly at the landin the core of the automatic stopping switc 8 is attractedby its stationary 120 and contacts 148 and 149 are t us interrupting ower to the elevator motor armature, bra 'e magnet coil and other operating circuits. Dynamic stopping resistance 265 is connected across the elevator motor armature through contacts 168 and 167 and contacts 266 and 267, lines 198, 172 and 176, and lines 191, 180 and 179 respectively. Y

InFigure 3, the motor generator set 268 consists of a shunt wound motor 279 driving a generator 274 obtainin power from the ower feeders through main line switch 269.

he separately excited field 273 of the genera'tor 274 is connected across the ower su ply feeders 270 and 271 from eeder 2 0 line 275,

through line 277, resistance 276 field winding 273, .line 272 to feeder 271.

Protective resistance 278 is connected across the shunt field winding from line 275 to feeder 271, to line 272.

The separately excited field 10, and its rotective resistance 12,' of elevator motor 2 1S connected permanently across feeders 270 and 271 through lines 280 and 281.

The elevator may be started in the up direction by moving car switch handle 6 to the extreme left hand position. After 0 erating circuits havebeen established by th car switch 5, car switch handle 6 may be returned. to neutral position and the elevator will continue to accelerate to a point midway betweenthe landing from which it has started and the adjacent landing above.

-At this midway point, the slow-down will be initiated, and the series field winding 11 will be connected in series with the elevator motor armature, being accumulative or differential depending upon the flow ofv current through its winding. By connecting the series field winding 11 in a manner that is' commonly known as difierentially compounded, the elevator inotor will be accumulatively compounded when delivering energy are completed by contactor 282 bridging e remeans and differentially compounded when receiving energy.

his permits series field winding 11 to assist in slowing down the elevator motor and at slow speed to increase the speed with load to counteract the effect of gravity b the change in kinetic energy due to spec add to that of field winding 10 thereby increasing the field strength and decreasing the speed.

Stopping is accomplished by interrupting current to the elevator motor armature, applying a dynamic stopping resistance across the elevator motor armature and applying the brake. By .holding car switch han le 6 in its extreme position, the elevator will continue to run at full speed, after it has accelerated, until the operator centers handle 6, when it will sto at the next landing beyond the first s ow-down switch it encounters. 1

The circuits established by moving handle 6 over are those for thelcoils of the up direction and fast speed switches and they contact finger points 283, 284 and 285. T

ective paths are from contact point 285 iiirou h contactor 282 'to contact point 283 and from contact point 285 through contactor 282 to contact,point 284. The bridging of these contactpoints is done for thepurpose of short-cii puiting resistance 286, the circuits extending from contact finger 283 through line 287, resistancef286, line 288, I contacts 299 and 300, lines 301, 302 and 303 for the up direction switch ma et circuit; and for the purpose of short-clrcuiting resistance 307 from contact finger 284, through lines 305 and 306, resistance 307, line 308, contacts 309 and 310, lines 311, 302 and 303 4 to contact finger 285. The short-circuiting of resistances 286 and 307 increases the current in these circuits, ermittin these magnet controlled switc es to c ose. These switches having closed remain closed after the car switch handle has been returned to neutral, the magnet coil circuits then extending through resistances 286 and 307 and contacts 299 and 300 and contacts 309 and 310.

Consider now the elevator tobe run one floor in the up direction and to be stopped automatically at the adjacent landing Car switch handle 6 is moved to the extreme left hand position and returned to neutral position immediatel Circuits from start cuit extending from feeder 270 through fuse 312, lines 313, 314 and 315, up direction switch magnet coil 316, line 317, contacts 318 and 319 of the terminal stopping switch, lines 320 and 287, contact .finger point 283, contactor 282, contact finger point 285, lines 303 and 304, contacts-321 and322, line 323,

.fuse 324 to feeder27 1. When car switch handle 6 is returned to neutral, thiscircuit takes the path from line 320, through resistance 286, line 288, automatic stopping switch contacts 299 and 300, lines 301 and 302 and-back on 304 as before. The up direction switch is closed by the magnet coil 316, which closes contacts 325 and 326, 327 and 328, 329 and 330 and 331 and 332 and opens contacts 333 and 334 and 335 and 336.

The closing of contacts 325 and 326 permits and 325,1ine 337, brake magnet coil 3 and protective resistance 4, line 338 to feeder 271. The brake magnet coil 3 being energized, releases the brake shoes from the brake wheel permitting the elevator motor armature to rotate. The armature of the elevator motor receives power from generator 274, the circuit being from the generator armature through line 339, contacts 330 and 329, lines 340 and 341, armature winding of elevator motor 2, lines 342, 343 and 344, contacts 331 and 332, line 345, contacts 346 and 347. line 348 and back to generator armature.

The elevator motor is now at slow speed but as a circuit isestablished for the fast speed ma net coil, the fast speed switch closes an immediate acceleration is obtained. This circuit extends from feeder 270, through fuse 312, line 313, contacts 326 and 325, lines 337 and 349, fast speed magnet coil 350, line 351, contacts 352 and 353 of the terminal stopping switch, lines 354 and 305, contact finger 284, contactor 282,

.contact finger 285, lines 303 and 304, contacts 321 and 322, line 323, fuse 324 to feeder 271. Upon restoring car switch handle 6 to neutral position, a self-holding circuit for the fast speed magnet coil is still established ance 276 in series with the field winding 273 of thegenerator 274. The voltage of generator 274 buildsup to full potential, accelerating elevator motor 2, the armature of which is supplied with power from generator 274. The opening of contacts 357 and has no function at this time.

' The magnet coils 259 and 260 which are in parallel, are utilized to energize the automatic stopping switch 8 and the automatic slow-down switch 7. The circuit for these magnet coils is obtained from feeder 270 through fuse 312, line'313, contacts 326 and 325, lines 337 and 361, magnet coils 359 and 360, lines 362, 363 and 323, fuse 324 to feeder 271. Upon reaching a point midway 'be tween the adjacent floors constituting the run, the core of switch 7 is attracted by stationary armature 364, thereby opening contacts 309 and 310 and initiating the slowdown by deenergizing fast speed magnet coil 350 and releasing its switch thus inserting resistance 276 in the circuit of field winding 273 of the generator 274 and the voltage of generator 274 decreases with decrease of field strength. Switch 7 also closes contacts 365 and 366 completing a circuit from feeder 27 0 through fuse 312, line 313, contacts 326 and 325, lines 337, 361 and 367, contacts 366 and 365, line 368, contacts 327 and 328,1ines 369 and 370, contacts 357 and 358 which are now closed by the release of the fast speed switch, line 371, compensating switch magnet coil 372, lines 363 and 323, fuse 324 to feeder 271.

' After switch 7 has passed beyond the range of armature 364, the circuit established will still remain effective by the use of resistance 373 connected across contacts 366 and 365. The resistance 373 is used for the purpose of permitting magnet coil 372 to hold in the switch controlled once it has closed, but will prevent the magnet coil 372 from operating its switch when it is open.

The com ensating switch closes contacts 374 and 3 5, which connects series field windin 11 of motor 2 across contacts 346 and 34 through lines 375 and 376 after which contacts 346 and 347 are opened, connecting the series field winding into the armature circuit of the elevator motor 2. This permits the series field winding to assist in the retardation and compensate for gravity by a change in kinetic energy.

The elevator approaches low speed suitable for the load after which the elevator will be nearly to the landing at which it is desired to stop. At this time the core of switch 8 will be attracted'by armature 377 thereby opening contacts 299 and 300 which will open the up direction switch magnet coil circuit releasing the switch controlled by it to interrupt power to the elevator motor armature, deenergize .brake magnet coil 3 permitting the brake to apply and connect dynamic stopping resistance 378" across arswitch other operating circuits that were closed during the starting up are opened and contacts and circuits once again are as shown in the wiring diagram Figure 3.

The operation and circuits have been describedin connection with the drawings for the up direction of travel only. It will be understood that down direction is obtained e circuits are all shown but not desc'ri Magnetic slow-down and stopping switches are shown diagrammatically and may be of any suitable construction but the preferred form is the subject of my copending ap 1ication Serial No. 619,426. It will be un erstood' that there are stationary armatures for these switches at each floor, althou h those for but one floor are shown in t e drawings, in order, to simplify the diagrams. It is also apparent that switches operated mechanically b cams in the hatch may be used, if desire Other modifications of control may be made without departing from the spirit of my invention.

I claim 1. An electric elevator system comprisin a hoisting motor, a separately excited winding winding fie d winding for said motor, aseries field for said motor, and means for connecting said series field winding in the armature circuit of said motor only during periods of retardation.

2. An electric elevator system comprising,

a hoisting motor, a separately excited field or said motor, a-series field winding for said motor, and means for connecting said series field windin in the'armature circuit of said motor only uring periods of retardation and in such manner that its magnetizing force op oses that due to the separately excited fie d winding when the motor is receivin energy.

3. An electric e evator system comprising, a hoistin motor, a separately excited field winding or said motor, a series field winding for said motor, and means for connecting said series field windin in the armature circuit of said motor only uring periods of retardation and in such manner as to assist the separately excited field winding while the motor is deliverin ener y and to oppose the separately excite fiel winding while the motor is receiving energy.

4. An electric elevator system comprising, a hoisting motor, a separately excited field winding or said motor, a series field winding for said motor disconnected during periods of acceleration and full speed running, and means'for conne ting saidseries car switch handle 6 to the right.

ed. ing for said motor disconnected during ,pe-

6. An electric elevator system comprisin a hoisting motor, a separately excited fie d winding for said motor, a series field wind riods of acceleration and'full speed running and means for causing the retardation oi said motor, saidmeans'includin means for connecting said series field'win ing inthe armature circuit of said motor.

7. An electric elevator systemcomprising, '1

a hoisting motor, a separately excited field winding for said motor, a series field winding for said motor disconnected during periods of acceleration and full s ed running, and means for connecting said series field winding in the armature circuit of said motor during periods of retardation and in such manner as to assist the separatel excited field winding while the motor is eliveringenergy and tooppose the separately excited fieldwinding while the motor is receiving energy. v

8. An electric elevator system comprising, a hoisting motor, a separately excited fie d winding for said motor, a series field winding for said motor, and means for introduc- I ing said series field winding into the arma ing for said motor, and means for introducing said series field winding into the arma-' ture circuit of the motor during periods of retardation in such manner that it assists the separately excited field winding while the motor is delivering energy and opposes the separately excited field winding while.

the motor is receiving energy.

10. An electric elevator system comprising, a hoisting motor-Ea? separately excited field winding for said is receiving ener regard essof the direction of rotation o the motor, and means for introducing said series field winding into the motor armature circuit during retardation.

11. An electric elevator system comprising in combination, a hoisting motor, a sepmotor, a series field winding for said motor for opposin the sap-- arately excited field windin whilet e motor aratel excited field for said motor, a series separately excited field while said motor is delivering current and to oppose the sepa rately excited field while said motor is drawing current from the line only during periods, of retardation and subsequent slowspeed running.

12. An electric elevator system comprising in combination, a hoisting motor, a separatel excited field for said motor, a series field or said motor, and means for connecting said series field in the armature circuit of said motor during periods of retardation and subsequent slow-speed running and for disconnectmg. said serles field from the armature circuit, during periods of acceleration and full-speed running.

13. An electric elevator system comprising in combination, a hoisting'motor, a separately excited field for said motor, and a series field for said motor, means for automatically connecting said series field in the armature circuit of said motor during periods of retardation and subsequent slowspeed running and for automatically disconnecting said series field from the armature circuit during periods of acceleration and full-speed runnmg.

14. An electric elevator system comprising in combination a hoisting motor, a separatelyexcited field for said motor, a series field for said motor, and means for connecting said series field in the armature circuit of said motor during periods of retardation and subsequent slow-speed running so as to assist the separately excited field while said motor is delivering current and to opposethe separately excited field while said motor is drawing current from the line and for disconnecting said series field from the armature circuit' acceleration and full-s%ed runnm GRAHAM enosv NOR.

of said motor during periods of

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