US1559814A - Motor controller - Google Patents

Description

Nov. 3 1925- 1,559,814 H. L. VAN VALKENBURG MOTOR CGNTROLLER Filed June 27, 1925 START STOP E/"mm L, Van I aMefl zazg @Zeww P Patented Nov. 3, 1925.

UNITED STATES 1,559,814 PATENT OFFICE.

HERMON L. VAN VALKENBUR-G, OF MILWAIIKEE, WISCONSIN, ASSIGNOR TO INDUS- TRIAL CONTROLLER COMPANY, OF MILNAUKEE, WISCONSIN, A CORPORATION OF WISCONSIN.

I\[0TOR CONTROLLER.

Application filed June 27, 1325. Serial No, 39,946.

To all whom it may concern:

Be it known that I, HERMON L. VAN VALKENBURG, a citizen of the United States, residing at Milwaukee, in the county of Milwaukee and State of \Visconsin, have 1nvented a certain new and useful Improvement in Motor Controllers, of which the following is a specification.

My invention relates to motor controllers, and the general object of the invention 1S. to provide an improved construction which will require the operator to remain in attendance for a predetermined period after he has turned the current into the motor. The apparatus is particularly adapted for use with motors driving laundry extractors which require a long starting period and where it is desirable that the operator remain at the machine until it is practically up to speed. The apparatus may be used, however, under any similar circumstances where the machine driven possesses a large amount of inertia and requires a comparatively long time to reach full speed or where for any other reason it is desirable that the attendant stand by for a given period of time after first starting the motor. My apparatus includes controlling switches and one of the contributory objects of theinvention is to provide means for causing these to make and break contact quickly at the proper moment. Another object is to provide a signal which will inform the operator when the conditions are proper for him to leave. Still another object is to provide means for cutting the coil of the timing mechanism out of circuit after it has served its purpose.

I obtain my objects by the apparatusillustrated in the accompanying diagram which shows one form in which the invention may be embodied.

The apparatus shown in the diagram is for a three-phase induction motor M of the type that can be thrown directly across the line, although the apparatus is applicable to other types of motors. The main motor switch has three arms 10, 12, 14 adapted to engage respectively with terminals 11, 13, 15 on the three supply conductors 16, 18, 20. These arms are all. fastened to a common starter shaft 22 and are operated by it. The shaft is rotatable so as to rock in its bearings and is operated by an arm 24 which is secured to the same rock shaft 22 and constitutes the armature of an electromagnet which includes a core 26 and winding 28 for magnetizing it. The motor leads 30, 32, 34 are connected respectively to the switch arms 10, 12, 14. v

Rigidly fastened to rock shaft 22 of. the main switch is an arm 36 which extends across the end of a plunger rod 38. This rod has a collar 40 fastened to it which rests upon a compression spring 42 which in turn rests upon stationary platform 44. The construction is such that, normally, if no current is flowing in coil 28 the spring 42 will hold plunger 38 in elevated position and this in turn will hold the armature 24 away from core 26 and switch arms 1O, l2, 14 out of engagement with the supply conductors 15, 18, 20. If coil 28 is energized it draws the armature 24 towards it which I rotates arm 36 in a clockwise direction in the diagram, thus depressing plunger 38 in opposition to the force of spring 42. When the coil 28 is energized it draws armature 24 to it, which causes the rock shaft to close the main motor switch and also depresses plunger 38.

Now to describe the elements which oblige the operator to keep his hand on the starting button for a certain period: The plunger 38 rests upon a take-up spring 46 which in turn rests upon a switch stem 48. This stem is encased in an insulating sleeve 50 which is pinned to it and to a. guide cylinder 52. This sleeve abuts the under side of platform 44 which thus forms a stop for limiting its upward movement. The guide cylinder is axially bored at the upper end to permit the plunger 38 to slide relatively to it. Said cylinder is chambered at the lower portion to enclose the spring 46 and near its upper end has an internal annular shoulder 54 which serves as a stop cooperating with a head 56 formed at the lower end of the stem 58.

Rigidly attached to the stem are three contactors 60, 62, 64. When the stem is in uppermost position the contactor 6O bridges the stationary contacts 66-, 68. When the stem is in lowermost position the contactor 62 bridges the stationary contacts 70, .72 and the contactor 64 bridges the stationary contacts 74, 76.

The stem is held in uppermost position by means of a detent 80 which engages the lower end of cylinder 52. It is pivotally mounted upon a stationary shaft 82 and is operated by an arm 84 overlying a trip pin 86 which is vertically. slidable in a center sleeve 88 forming part of the frame of an elertromagnet. This magnet has a coil 90 and a vertically movable core 92. Beneath the magnet frame is a dash pot 94 having a plunger 96 which is connected to the core and retards its upward movement. The construction is such that when coil 90 is energized it will slowly raise core 92 and cause it to elevate trip pin 86, which in turn will operate the arm 84 and detent 80 and permit the latter to release the cylinder 52. If, when the cylinder is released, the

takeup spring 46 is under compression, as

is the case under normal operating conditions, said spring will cause the stem 48 to quickly descend and change the position of the contactors 60, 62, 64.

The apparatus is equipped with a' manually operated starting switch which includes a switch arm 100 which is normally held by a tension spring 102 out of engagement with a stationary contact 104. This switch is operated by a push button 106. The apparatus is also equipped with a manually operated stop switch which includes a switch arm 108, which is normally held by a tension spring 110 in engagement with a stationary contact 112. This switch is operated by a push button 114.

Switch arm 10 is connected to a conductor 120 which is connected to a conductor 122 leading to coil 90. From coil 90 a conductor 124 leads to contact 56. Switch arm 14'is connected by a conductor 126 to stationary contact 68. Conductor 120 is connected by a conductor 128 to a resistance 130. This resistance is connected by a conductor 132 to stationary contact 74. Stationary contact 76 is connected by a conductor 134 to a signal lamp 136. A conductor 138 leads from the .lamp to a conductor 140 which is connected to thgstationary contact 70. A conductor 142 connects the conductors 138 and 140 to the stationary contact 104. A conductor 144 connects the conductors 138, 140 and 142 to the stationary contact 112. A conductor 146 connects the switch arm 108 to one end of the coil 28. The other end of the coil is connected by a conductor 148 to the supply conductor 16. The switch arm 100 is connected by a conductor 150 to a conductor 152 which is connected to the supply conductor 20. A conductor 154 connects the conductors 150 and 152 to the stationary contact 72.

Operation: Let it be assumed that the apparatus is in the condition shown in the diagram, the main motor switch arms 10, 12, 14 being in open position, the core 26 of the operating magnet being deenergized, the

coil of the time limit relay being deenergized, and the detent 80 holding the stem 48 in elevated position. The starting switch arm is in open position, and the stopping switch arm 108 is in closed position.

If, now, the operator wishes to start the motor he presses the start button 106 and brings the arm 100 into engagement with the stationary contact 104. The coil 28 becomes energized as follows: current passes from the supply conductor 20 through conductors 152 and 150, to switch arm 100, thence through the contact 104 and conductors 142 and 144 to the stationary contact 112, thence through the switch arm 108 to the conductor 146, thence through coil 28 and conductor 148 to supply conductor 16 on the other side of the line. The energization of coil 28- causes the arm 44 to swing into engage ment with the core 26 and this rotates rock shaft 22 and brings the switch arms 10, 12, 14 into engagement with the contacts 11, 13, 15 respectively at the terminals of the supply conductors 16, 18, 20 respectively- This connects the motor across the line and causes 1 it to start rotating. Y

The motion of the rock shaft also causes arm 36 to descend, which depresses the plunger 38 in opposition to the force of springs 42 and 46. The closing of the main motor switch arms 10, 12, 14 also causes the time limit relay coil 90 to become energized as 'follows: from switch arm 10 the current passes to conductor 120; thence through conductor 122 to the coil 90; thence through conductor 124 to stationary contact 66; thence through the movable contactor 60 to the stationary contacts 68; thence through the conductor 126 and switch arm 14 to the Supply conductor 20. This energization of the coil 90 tends to raise the movable core 92, but the motion'of the latter is retarded by the plunger 96 of the dash pot and hence moves but slowly, thus giving the motor M time to pick up speed. As the core approaches the top of its movement it engages the trip pin 86 and the upward movement of the latter raises arm 84 and causes the detent 80 to release cylinder 52 and stem 48. Thereupon the takeup spring46, which has been compressed by the descent of the plunger 48, causes the contactor 60 to descend and open the circuit through the coil 90. At the same time the lowering of the stem moves the contactors 62 and 64 into engagement with their 00- lamp notifies him that the preliminary starting period has been completed and that the main switch will remain in closed position even though he releases the starting switch. I will now trace the circuit of the signal lamp and of the main operating coil 28 which remains energized. The coil is energized as follows: From the supply conductor the current passes through the conductors 152 and 154 to the stationary contact 7 2; thence through the contactor 62 to the contact 7 0; thence the current passes through the conductor 140 and 144 to the stationary contact 112; thence the current passes through the switch arm 108 of the stop switch; thence through conductor 146 to coil 28; thence through the coil and conductor 148 to the opposite side of the line. Thus it will be evident that after the time limit has 'expired V the relay coil 90 will be cut out of circuit and the circuit will be maintained through the contactor 62.

The signal lamp 136 will be energized as follows: The current will pass through the switch arm 10, conductors 120 and 128 to the resistance 130, thence through the conductor l 132 to the stationary contact 74, thence through the contactor 64 to the contact 76; thence through the conductor 134 to the lamp 136; thence through the conductors 138 and 140- to the stationary contact 70; thence through the contactor 62 to the stationary contact 72; thence through the conductors 154 and 152 to the supply conductor 20 which is on the opposite side of the line.

Having thus described my invention what I claim as new and desire to'secure by Letters Patent is:

4 1. In combination, an electroresponsive device, a switch operable to cause said device to respond but tending when released to deenergize said device, and electroresponsive means for preventing said switch from deenergizing said device but necessitating manual retention of said switch for a temporary period after the response of said device, said electroresponsive means having a mechanical retarding device for regulating its operation.

motor but tending when released to stop the I motor, electroresponsive means adapted to prevent said switch from stopping the motor, and a retarding device for delaying the response of said electroresponsive means when said switch is manually operated, whereby manual retention of said switch is necessitated until after the lapse of a predetermined interval of time. p

4. A controller for electric motors having a switch operable to start the motor but tending to moveto a position to stop the same, a retarding device and automatic means for preventing said switch from stopping the motor, but necessitating manual retention of said switch until after the. lapse of the period of operation of said retarding device.

5. In a motor controller, a manual switch controlling the continuity of the circuit of the motor and tending to move to a position to cause the motor circuit to be interrupted, a maintaining circuit for also controlling the continuity of the circuit of said motor, electroresponsive means for closing said maintaining circuit, and a re? tarding device for delaying the response of said electroresponsive means, whereby said electroresponsive means is unable to close the maintaining circuit until after the lapse of a predetermined period after the manual switch is operated.

6. In a controller for electric motors, the combination with a motor circuit of an electroresponsive motor switch for controlling the continuity thereof, a manual switch for energizing said electroresponsive switch but tending when released to deenergize the same, a maintaining circuit for keeping the winding of the motor switch energized, an automatic switch for controlling the maintainingcircuit, the action of said automatic switch being initiated by the manual operation of said manual switch, and a retarding device for retarding the action of the automatic switch to thereby prevent the automatic switch from closing the maintaining circuit until after the lapse of the operating period of the retarding device following the manual operation of the manual switch. 2'. In combination, an electroresponsive,

7. A motor controller having a motor switch through" which current may be supplied to the motor, an electroresponsive device' for closing it, a manual switch for causing said device to respond, said manual switch when released tending to cause said electro-responsive device to release the motor switch, and a time limit relay having a maintaining circuit arranged in parallel with the circuit of the manual switch, said time limit relay being electroresponsive and'controlled in part by the main motor switch, whereby the time limit relay will -not cause the motor switch to remain closed unless the manual switch is manually held for a predetermined period after the motor switch is closed.

8. A motor controller having a motor Cal lGO

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switch through which current may be sup plied to the motor, an electroresponsive device for closing it, a manual switch for caus: ing said device to respond, said manual switch when released tending to cause said electro-responsive device to release the motor switch, a maintaining circuit for caus ing said electroresponsive device to keep the motor switch closed, an automatic switch which when released causes the maintain ing circuit acting through the electroresponsive device to release the motor switch,

electroresponsive means for releasing said automatic switch, said electroresponsive means being controlled by the motor switch whereby it commences to respond at the time the motor switch is closed, and, a retar-ding device for preventing said electrorcsponsive means to release the automatic switch until a predetermined interval has elapsed after the closure of the motor switch.

In witness whereof, I have hereunto subscribed my name.

HERMON L. VAN VALKENBURG.

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