US1243571A

US1243571A - Electric controlling system.

Info

Publication number: US1243571A
Application number: US3734615A
Authority: US
Inventors: Herbert S Valentine
Original assignee: Link Belt Co
Current assignee: Link Belt Co
Priority date: 1915-06-30
Filing date: 1915-06-30
Publication date: 1917-10-16
Anticipated expiration: 1934-10-16

Description

H. S. VALENTINE.

ELECTRIC CONTROLLING SYSTEM.

APPLICATION FILED JUNE 30. I915.

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,H. S. VALENTINE.

ELECTRIC CONTROLLING SYSTEM.

APPLICATION FILED JUNE 30.1915L Patented Oct. 16,1917.

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HERBERT S. VALENTINE, OF PHILADELPHIA,

OF PHILADELPHIA, PENNSYLVANIA, A CORPORATION OF ILLINOIS.

BELT COMPANY,

PENNSYLVANIA, ASSIG-NOB TO LINK- ELECTRIC CONTROLLING SYSTEM.

' Application filed June 30,1915. Serial No. 87,846.

To all whom it may concern:

Be it known that I, HERBERT S. VALEN- TINE, a citizen of the United States, residing in Philadelphia, Pennsylvania, have invented certain Improvements in Electric Controlling S stems, of which the following)is a speci cation.

ne object of my invention is to provide a system for controlling a motor particularly of the type used on cranes and hoists, in which the apparatus shall be so arranged that a break at any point. and more specially, in the resistance, shall necessarily result in the o eration of the holding brake.

It is furt er desired to provide a motor controlling system including a solenoid or similar brake, a controller, and controlling resistance, in the resistance will cut ofi' current from the brake winding and thereby cause setting of the holding brake at any running position of the controller.

Another object of my invention is to provide a novel combination of a hoisting m0- tor, resistance and controller with the associated connections particularly designed to result in relatively highly efiiclent operation of said motor when it is used for lowering as well as when it is employed to hoist a load.

These objects and other advantageous ends I secure as hereinafter set forth, reference being had to the accompanying drawin 's, in which,

I igure 1 is a diagrammatic view of the apparatus comprising my invention, and

Figs. 2 to 7 inclusive are diagrams illustrating the connections of the apparatus included in my invention under various conditions of its operation.

In the above drawings 1 represents the armature and 2 the field windings of an electric motor, of which the latter is directly connected to one terminal of a body of resistance 3 designed to limit the current flow when said motor is short circuited and positively driven as a generator. Directly connected to the second terminal ofthe resistance 3 is a controller blowout winding 4 which is likewise connected in series with the windin of an electric brake 5. This latter may e of any suitable form designed to operate when its winding is deenergized, to prevent rotation of the motor armature,

all so connected that a breakage field winding and the the left of the but designed to release the armature or apparatus to which it is connected as long as said brake winding is supplied with suitable current.

For governing the operation of the motor I provide a controller, shown in Fig. 1 with its contacts and fingers as dia rammatically developed. Said fingers are mdicated-at 6 to 17 and are so placed as to cooperate with either of two sets of contact strips or segments preferably mounted on a rotary barrel of the well known form.

Banks of

resistance

18, 19 and 20 are connected between the fingers 1213, 13-44:, and 1415, and the finger 6 is connected to one terminal of a source of current supply, while the finger 17 is connected to the second terminal of such source. The finger 7 is permanently connected to one of the armature and field winding, while the finger 8 is connected to the second armature terminal and also to the finger 11. The finger'9 through a suitable conductor connects between the second terminal of the resistance 3, while the finger 10 is connected to the conductor extending between the resistance 3 and the blowout winding 4.

The finger 12 is connected through the winding of the brake 5 to the second terminal of the blowout winding 4, while the

fingers

15 and 16 are directly connected together. Without specifically describing the detail arrangement of the controller contacts or segments which cooperate with the various fingers 6 to 17 inclusive, it is noted that those to the right of the line of the fingers are designed to be utilized when the motor is operated to raise a load, and of these contacts the ones cooperating with the fingers 10 and 11 are extended so as to be in engagement with said fingers when the controller is in its off position. Since these contacts are permanently connected together, when the controller is in this position the motor is short circuited and its circuit consists of the elements shown in Fig. 7. Similarly, the contacts or segments to line of fingers are designed for use when a load is being lowered.

As the controller is operated to successively bring the contacts or segments X into engagement with their coiiperating fingers, the apparatus is. connected as shown in Patented Oct. 16, 1917.

terminal each- Fig. 6 with the field winding 2 in series with the

resistance banks

18, 19 and 20, thereby causing the motor to be speededup until it is finally connected directly across the line with the resistance 3 and electric brake winding 5 still in series with it, so that obviously an open circuit occurring in the resistance, necessarily deenergizes the winding of the brake solenoid, which when the system is used with a hoisting motor, at once causes application of the brake and prevents dropping of the load which is being raised.

If new the controller be turned from its full-on position to its off position, the motor under certain conditions will be. driven by the load which it has been raising, so that when the controller cylinder is, in such off position, the motor is short circuited through the resistance 3 and acts as a genorator. Under these conditions the current fiow is kept within predetermined limits by said resistance and the machine acts as a dynamic brake to prevent a dangerously rapid descent of the load.

When it is desired to drive the motor so as to positively lower the load, the moving of the controller barrel to bring the contacts Y into engagement with the various fingers causes'the apparatus to be successively connected as indicated in :Figs. 2 to 5 inclusive. On the first point the field winding 2 which is connected in series with the limiting resistance 3, the winding of the brake 5 and the resistance bank 20, is with them in parallel with the armature 1, and with the latter in series with the resistance On the second and third points the connections of the armature remain as before while the flow of current through the field winding is weakened by first connecting it in series with the resistance bank 18 and then adding to its circuit the resistance bank 19. On the last point, the armature of the motor is' directly connected across the line, while the current through the field is out down as far as possible by connecting in series with it the three banks of

resistance

18, 19 and 20. On all of these points the winding of the electric brake 5 is always in series with whatever part of the resistance is in circuit or is so connected that the cutting off of current from the motor circuit will 1. With such an arrangement of parts, after the motor has been operated to raise a load to a predetermined height, some part of the hoisting mechanism so engages the switch 25 as to open the same and thereby cut off current from the armature 1, whereupon the motor with its attached apparatus comes to rest.

Hitherto it has either been necessary for the overtravel switch 25 to be manually closed before the apparatus could again be put in service, ora separatetrolley wire, with the extra contacts, fingers and connections were employed, but with the connections above described this is unnecessary, since if the controller be operated to bring the contacts Y into engagement with the various fingers, it will be noted that even though the switch 25is open, current is free to flow from the finger 6 to the uppermost of the Y contacts, thence to the contact next beneath the same,

the finger 7, conductor 26, through the armature 1, and through the finger 11 to the other apparatus of the system as previously described. The motor is thus started in such a direction as to lower the load and the switch 25 is closed by gravity or by the action of a spring.

This last described feature is an important element of my invention, for it permits of the reversal of the motor even while the overtravel switch is still open, and causes the automatic closing of said switch, so that after lowering the apparatus may be at once put into service to hoist a load.

I claim A system including a. motor; an overtravel switch therefor; and a controller for the motor including means for shunting said switch to permit reversal of the motor when said switch is open; said means including two conductors leading from one of the fingers of the controller and connected on opposite sides of said switch.

HERBERT S. VALENTINE.