US1557428A - Electric-motor load-controlling device - Google Patents

Description

R. CONRADER ELECTRIC MOTOR LOAD CONTROLLING DEVICE Oct. 13, 1925 1,557,428

Original Filed Dec. l, 1921 3 Sheets-Sheet l @C59 O 0,9 O' f /22 Oct 13l 1925 1,557,428 R. CONRADER ELECTRIC MGTOR LOAD CONTROLLING DEVICE original Filed Deo. 1, 1921 s sheets-shea 2 Oct. 13, 1925. 1,557,428

R. CONRADER ELECTRIC MOTOR LOAD CONTROLLING DEVICE original Filed Deo. 1. 1921 :ssheets--sheet MMIII! IIIHII Patented Oct. 13, 1925.

UNITED STATES RUDOLPE'CONRADER, 0F ERIE, PENNSYLVANIA.

ELECTRIC-KOTOR LOAD-CONTROLLING- DEVICE.

Application med December 1, .1921, Serial' No. 519,166. Renewed Hay 6, 1925.

To allfwhomitfmuy concern. f

Y Be it known that I, RUDOLPH CONRADER, a citizenof the United States, residingat Erie, in the county of Erie and State of Pennsylvania, have invented new and useful Improvements in Electric-Motor Load- Controlling Devices, of which the following is a specification.

In starting electric motor-driven mechanism such as pumps and compressors lit is desirable with most motors and necessary with some to getthe motor up to speed before subjecting it to its load. The present invention is designed to automatically take care of the load as the starting switch, usually of the rheostat type is operated so that the load is only placed on the motor after it has reached its speed. Preferably the control mechanism is supplemented with a regulator which will control the load'in response to variations of pressure especially where the device is usedfon a pump. Details and other features of the invention will appear from the specification and claims.

The invention-is illustrated in the accompanying drawings as follows Fig. 1 is a section on the line 1--1 of the rheostat and controlling valve.

Fig. 2 a front elevation of the rheostat with the controlling valve in section.

Fig. 3 a side elevation of a pump with the controlling devices attached. Fig. 4 a side elevation, partly in section, fof an unloader.

Fig. 5 a section of an inlet unloader.

.Fig. 6 a side elevation, partly in section, of a pilot valve.

Fig. 7 a section onthe line 7-v-7 in Fig. 6.

Fig. 84 an enlarged view of the spring actuating the switch lever.

1 marks a pump cylinder, 2 a crank shaft from which the pump is operated, 3 a drive pulley on the crank shaft, 4 an electric motor from which the drive pulley 3 is driven. and 5 the discharge ipe from the pump. The discharge from t e pump leads to the inlet connection 6 of the undloader.

The unloader has a body 7 in which is arranged a-n inlet chamber 8, discharge chamber .9, and unloader chamber 10, lfthe unloader chamber preferably connecting through a pipe 10 with the inlet of the pump. A passage 11 connects the inlet chamber 8 with the discharge chamber 9. It

is surrounded by a valve seat 12 on which the valve 14 operates to close the passage. The valve 14 is carried by a stem 15. A passage 16 connects the inlet passage with the unloader passage. The passage' 16 is surrounded by a seat 17 on which an unloader valve 18 operates, the unloader valve being carried by a plunger 19 operating ina cylinder 20. The cylinder is connected by a passage 21 with a control chamber 21. The specific formy of unloader forms no part of the invention. In its operation the plunger 19l is subjected to the pressure of the control chamber Which pressure is controlled, the maximum pressure being ordinarily receiver pressure and introduced to the chamber when the receiver, or receptacle, pressure gets below that desired. Under these conditions pressure on the plunger closes the valve 18, the face of the valve being of considerably less area than the plunger so that the two faces being subjected to the same pressure the dominant pressure on the plunger seats the valve. When it is desired to unload, pressure is exhausted from the chamber 21 and the pressure on the face of the valve opens the. valve and unloads the pump. The stein 15, it will be noted, is subjected at one end to the controlled chamber pressure and at the other end to pressure at the discharge side of the valve 14. Under these conditions the pressure on this stem is practically balanced while I'the pump is working and the valve 14 open but when the pressure is exhausted from the chamber 21 this unbalances the stem 15 and this elfects,

the closing of the valve 14, thus preventin a return flow of' fluid during the unloa ing operation. The specific unloader described forms the subject matter of a companion application, unloader, Serial Number 519,164. The controlling switch or rheov stat 22 is provided with the usual arm 23 operating over the contacts 24 of the rheostat. In the final position the arm-23 engages an electric magnet 25, the coil of which has the wires c leading from the main wires a and b controlling the motor. So long as the current is passing to the motor the arm 23 is retained y the magnet. The arm is supplied with the usual coil s ring 23 which acting on the arm tends to t row it away from the electric magnet. and to the initial position shown in dash lines which i opens the switch. This is a common construction the purpose of which is well understood.

It is desirable that with each starting the load lbe taken oill the motor and this is true whether started initially or after a temporary pause in the current. This is accomplished in the present invention as follows: The controlling valve has the body 25. This body has the cont-rol passage 26 from which a pipe 27 communicates with the4 unloader. Ponts 28 and 29 lead from the control paage 26 to the inlet passage 30 and exhaust passage 31 respectively. The inlet paage is connected by a` pipe 32 with the receiver pipe 9 leading from the Iunloader. Valves 34 and 35 control rthe ports 28 and 29. These valves are supplied with the 'v stems 36 and 37 respectively. The valve body is secured to a frame 38 by means of i a screw 39.- A spring cap 40 is slidingly 'mounted in thev frame. A push pin 41 extends into the cap and rests on the stem 37. A spring 42 rests on the push pin| 41 and is retained in the cap by the plug 43 having a rounded end 44. The @plug nelralizes the spring when the head of the push pin 41 engages fthe lower end of the cap but when the cap as a whole is depressed the push pin is spring-preed against the stem 37, vthus tending -to close the valve 35. The valve 35 has a small projection 35iL which engages a projection 34a on the valve 34 so th-at the closing of the valve 35 is accompanied. by the opening of the valve 34. A cam 45 is arranged on the hub of the arm 23 and engages the plug 43 of the cap 40 and moves the cap so as to reverse the valves with the final movement of the arm to position turning on the full current and bringing the arm under the influence of the magnet 25. A spring 46 operates against vthe stem 36 tending to close the valve 34 and to open the valve V35 but this spring is of less strength than the spring 42 so that with a depression of the cap 40 a reversal of the valves takes place but upon the release of the cap 40 the valve 34 is closed and the valve 35 is opened. The lower end of the spring 46 rests on a screw 47 by means of which the frame 38 issecured on a cap 48 at the top of a supporting pipe 49, the pipe 49 being screwed into a Hoor plate 50. By this construction providing the proper length of pipe 49 the device may be applied to the switch of ordinary installations without change of that installation such as is ordinarily mounted on the wall as indicated in Fig. 3.

The .operation of the mechanism so far as described is as follows: With the arm '23 initially open and the .switch open the though there is pressure in the receiver there is no pressure carried by way of the ipe 27 to the controlling chamber 21 of t e unloader and the unloader is in unloading position. As the arm 23 is moved forward turningfthe current into the motor, the motor is started with the unloaded ump and 'i as it progresses in its speed and t e control lever is advanced the control lever finally reaches a place near its ultimate position bringing the cam 45 into engagement with the cap 40 and with the final movement reversin the valves 'and bringing the arm 23 un er the influence of the magnet 25 so that as the operator releases the arm 23 it is held by the magnet 25 against the spring 23a. With a reversal of the valves in this final movement air is turned through the port 28 and the exhaust is closed. The air reaching the control chamber Voperates on the plunger 19 closing the valve 18, thus cutting out the unloader` and the pump `starts to work. If, for any reason the switch is thrown by cutting off the current or through the operator the cam 45 is moved away from the cap 40, thus releasin the cap and the valves are reversed throug lthe action of the spring 46. Upon the opening of the exhaust valve air is exhausted from the control chamber thus unloading the pump so that with a starting of the motor the pump starts unloaded.

. It is desirable to supply the unloader with a pilot valve, or regulator responsive to pressure so that after the motor is startedthe pump may unload and load in response to pressure requirements. I have provided such a ilot valve (the pilot valve forming the sub]ect matter of a companion application Serial Number 519,163, pressure controlled valve' mechanism), or regulator as follows:

' A valve body 55 is screwed into the chamber 21. This body has the control passage 56 connected by the orts 57 and 58 with the inlet passage 59 an exhaust passage 60 respectively. The passage 59 has a pipe con- 1 nection 61 and the passage 60 the pipe connection 62. The pipe connection 61 has the pipe 27 leading to it from the controlling valve. A valve 63 controls the port 57 and the valve 64 the port 58. Stems 65 and* 66 extend from the valves respectively. These stems are secured to the cross heads 67. Springs 68 extend from the ends of the cross heads to the valve body and tend to close the valves 63 and 64. Projections 69 en x the cross heads 67, the projections extending from a yoke 70. The yoke .70 has an opening 71 into which one end of a bell crank 72 extends. The bell crank is mounted on a pin 73 and is connected by a link 74 with a lever 75. The leverl 75 is mounted on a pin 76. A bearing point 77 is carried by a diaphragm. 78 and extends into a detent in the lever and communicates the movement of the diaphragm to the lever. The diaphragm is mounted in a diaphragm plate 7 9, the diaphragm being clamped on said plate by the cover 80. A passage 81 extends through the diaphragm plate communicating with the inlet passage 59 so that when the inlet or control valve is open the diaphragm is subjected to receiver or pump pressure. A screw-threaded projection 82 is arranged on the cover and a follower 83 is screwed into this projection. Aspring'84 is engaged by the follower and rests on a base plate 85 having a point extending into a detent in the lever 75, the spring opposing the movement of the diaphragm under pressure in the well-known manner. The operation oi the pilot valve is as follows: l-Vhen the receiver pressure rises above the predetermined pressure the diaphragm is moved carrying with it the lever 75 to the left. This closes the inlet valve 63 and opens the exhaust port 64, thus exhausting the air from the control chamber and from the back of A the plunger 19. This allows the valve 18 to open, thus unloading the pump in the manner hereinbefore described. On a-reduction of pressure o n the diaphragm the spring 84 moves the lever in the opposite direction closing the exhaust valve and opening the inlet valve, thus putting pressure on the control chamber and through the pressure on the plunger closing the valve 18 and subjecting the pump to pumping action.

It is desirable to vary lthe range of variation in pressure between the unloading and loading up of the pump and this is accomlished with this regulator as follows: The lever 75 has a V-shaped cam 86 which is engaged by a V-shaped cam 87. The cam 87 is carried by a lever 88. The lever 88 is mounted on a pin 89 carried by the diaphragm plate 79. A pin 90 extends from the cover plate through the lever. A spring 91 is arranged on the pin and a nut 92 exerts pressure on the spring. The operation of this device is as follows: With the initial movement in either direction the cam 87 assists in the resistance to the movement of the lever 75 but after the lever passes the intermediate point the cam 87 assists the movement. Consequently there is resistance to a reversal. The amount of resistance may be varied by adjusting the spring 91 by the nut 92 and the range of variation required to ell'ect the reversal may be thus enlarged or reduced.

This device may be adapted to an un.

valve has the 96 and is normally closedv by a spring 97. A plunger 98 is mounted in the cylinder 99. The plunger has an extension 100 engaging the stem 96. Aspring 101 returns the plunger and relieves the stem 96 so that the'valve may be closed. A pipe 102 extends to the regulator passage 56. The regula-tor or pilot valve is provided with a passage 103 in which there is a screw plug 104 when the device is operating on the unloader shown in Fig. 4. With an unloader operating with pressure the screw plug 104 is placed in the passage 81 and the valves are connected up as follows: .The pipe 32 carrying the receiver .pressure is connected to the passage 31 instead of the passage 30 and also connected direct to passage 59 and the vcontrol passage 26 is connected to the passage 59. The passage 30 is open to the atmosphere. Under these conditions at the start of the operation the valve 35 is open and the valve 34 closed Therefore pressure is delivered by way of the passage 26 and the passage 59. If the receiver pressure on the diaphragmthrough the connection to the passage 60 is less than the predetermined pressure the valve 63 which is normally the exhaust valve of the regulator will be open 'so as to load up the compressor but under the present conditions inasmuch as this exhaust is connected by way of the passage 26 and valve 35 with the pressure, pressure is delivered through this passage to back of the plunger 98 and the compressor is unloaded during this interval. If the pressure on the diaphragm is above the pre-determined pressure the valve 63 will be closed and the valve 64 opened and inasmuch as the passage 60 is at all times under receiver pressure, receiver pressure will pass by the valve 64 to the unloader and unload it so that with any ycondition of pressure in the receiver the unloader will be brought to untor. en the cam '45 operatesto close the valve 35 and open the valve 34 the unloader will continue in its unloading position, or will load up the compressor depending on the receiver pressure. If the receiver pres-A sure is below the desired pressure and this pressure is communicated to the diaphragm the valve 63 will be open and the valve 34 at this time being also open there is a direct exhaust from the cylinder 99 by wav of the valve63, 'passage26 and valve 34. lf, however, the receiver pressure is above thev desired pressure the -valve 63 will be closed and the valve 64 o ned, thus continuing the pressure on the pIlleinger 98 and continuing the compressor in loaded condition.

While I have shown a rheostat which inbroader phases' of my invention jI wish`tcA loadingvposition with the starting of the mo- Y I volves a device for making and breaking the device, the combination of an electricmotor- .include any device for making and breaking the current and have designated such a device a switch desiring to include by this designation any device which will control e the circuit. v

What I claimas new is 1. In an electric motor load controllin device, the combination of an electric motor manually actuated variable resistance controlling switch; an unloader; and means ac tuated 'as the switch is actuated for actuat ing the unloader.

controlling switch; a pressure actuatedunloader; a valve device controlling the unloader comprising connected control, inlet and exhaust passages, valves controlling said connections; and means acted on by the `switch as the switch is actuated for-actuating said valves alternately tov` control the unloader.

i 4. In an electric motor load controlling device,.the combination of an electric motor controlling switch,- a pressure actuated unloader; a valve device comprising connected control, inlet and exhaust passages; opposing valves controlling said connections; op-

: posing springs tending to closesaid valves,

one of said springs having greater strength than the other; means for neutralizlng the dominant spring; and means acting as the switchis actuated for actingon the dominant sprin to actuatethe valves to control the unloa er.

,- 5. In an electric motor load vlcontrolling device, the combination oan electric motor controlling rheostat having a series of contacts and an arm successively operating on sald contacts; a pressure-actuated unloader;

a valve device controlling the unloader com;

prising connected control, inlet and exhaust passages; opposing valves controlling said connections; opposing lsprings tending to close said valves, one of said springs having greater strength than the other; means for neutralizing the .dominant spring; and a cam on the 4arm act-ing on the dominant spring to reverse the valves to actuatethe valves to actuate the unloader.- 6.. In an -electric motor load -controlling device, the combination. of an electric motor controlling rheostat; comprising'a series of contacts and an'arm` operating over said by the arm for actuating the unloader as the l contacts; an unloader; `and devices carried arm is actuated.

. 7.' In an electric motor load controlling device, the combination of an electric motor4 controlling rheostatl comprising a series of contacts andan arm operating over the same; a pressure-actuated unloader; a valve controlling the 'unloader; and means comprising a cam carried by the arm for actuating the valve.

8. In an electric motor load controlling device; the combination of an electric motor controlling switch; electro-magnetic means for holding the switch in closed position; means opening the switch on a reduction of current in the circuit controlled by the switch; an unloader; and means actuated as the switch is actuated to open or close the switch actuating the unloader.

9. In an electric motor load `controlling device, the combination of an electric motor controlling switch;` electro-magnetic means holding the switch in'closed position; .means opening the switch on a reduction of the current in the circuit controlled by the` switch; a pressure actuated unloader; a valve controlling the pressure on the unloader to control the unloader; and means actuated as -the switch is actuated either closing or opening actuating the valve.

1 0. In an electric motor load controlling device, the combination of an electric motor controlling switch; an unloader; means actuated as the switch is actuated controlling the unloader; and a pressure actuated device controlling the unloader, said pressure actuated device operating independently of an action of the switch.

11. In an electric motor .load controlling device, the -combination of an electric motor controlling switch; a pressure-actuated -unloader; a valve controlling the unloader; means actuated as the switch is actuated controlling the valve; and a pressure-actuated valve controlling the unloader.

controlling switch; a -pressureactuated unloader; a valve controlling the unloader;

means actuated as the switch is actuated controlling the valve; anda pressure-actuated valve controllin' the unloader, said pressure-actuated va ve operating independently of the action of the valvecontrolled by the switch.

12. In an electric motor load controllingl device, the combination of an electric motor sol 13. In an electric.motor load controlling device, the combination-fof an electric motor controlling switch; an electro-magnetic reduction ,of the current controlledby the switch; an unloader; means'actua'ted as the switch is actuated to open or close the same controlling the unloader; and a pressureactuated device actuating the'unloader.

14. In an electric motor lead controlling device, the combination of an-electric motor controlling` switch;l an electro-magnetic 'means for holding the switch in closed position; means for opening the switch upon a means for holding the switch in closed position; means for opening the switch upon a reduction of the current controlled by the switch; an unloader; means actuated as the switch is actuated to open or close the samecontrolling the unloader; and a pressureactuated device actuating the unloader, said pressure'controlled device acting independently ofthe means controlled by the` switch.

15. In an electric motor load controlling device, the combination of a ypressure-actuated unloader; a regulating valve controlling said unloader comprising a control passage, an exhaust passage, and anl inlet passage; connections between the exhaust and inlet passages and the control passage; valves controlling said connections; a motor subjected to pressure actuating said valves; a control valve comprising a control passage, and exhaust and inlet passages; connections between the inlet and exhaust passages and the control passage; control valves 'controlling said connections; a connection between the control passage of thecontrolling valve and the inlet passageof the reglatmg valve; a switch controlling the electric motorr; and means actuating said controlling valves as the switch is actuated. v

16. In an electric motor load controlling device, the combination of anelectric motor; a controlling switch actuated by a lever; a spring operating on the lever tending to open the circuit; an electro-magnetic device normallyholding the lever in closed position; an unloader; and means actuated as the lever is actuated for actuating the unloader.

17. In an electric motor load controlling device, the combination of an electric motor; a controlling'switch actuated by a lever; a spring operating on the lever tending to open the circuit; an electro-magnetic device normally holding the lever'ini closed position; an unloader; means ,actuated as the lever is actuated for actuating the unloader; and a cam mechanism comprising an element carried by the lever for actuating the unloader.

In testimony whereof I have hereunto set my hand. g'

RUDOLPH co-NRADER.

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