Electricity: magnetically operated switches – magnets – and electr – Electromagnetically actuated switches – Retarded or delayed type
Patent
1984-08-09
1985-11-26
Broome, Harold
Electricity: magnetically operated switches, magnets, and electr
Electromagnetically actuated switches
Retarded or delayed type
335141, 337 54, H01H 706, H01H 4302
Patent
active
045556849
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
This invention relates to a motor starting device and in particular it relates to a device of the type which controls the energization of a start winding to run the motor up to speed to be then switched over to continued operation, the start winding being de-energized during the running period of the motor.
OBJECT OF THE INVENTION
Many forms of such devices have been known in the past, but the object of the present invention is to provide a device which introduces a time element in the switching of the start winding independent of the current draw which is taking place for instance in the electromagnetic coil, the purpose of this being to overcome the difficulty which exists at present when a motor is switched on and then switched off and again switched on without leaving a sufficient time delay for the mechanism to reset itself.
SUMMARY OF THE INVENTION
The present invention utilises an electromagnetic coil in the normal way in circuit with the motor winding which coil includes a spring loaded pivoted keeper which is pulled down by energization of the coil, but the motor start winding is controlled independently of this by a bimetallic strip connected so that there is a current flow through the bimetallic strip to the start winding through contacts under control of a contact blade held in position by a latch member which is arranged to be engaged and held by the bimetallic strip until such time as the bimetallic strip is sufficiently heated to release the latch member and break the hold by allowing the contact blade to return.
Thus the invention relates in general to a motor starting device adapted to de-energize the starter winding when the motor has attained the required speed and torque, and according to a preferred form a housing supports an electromagnetic coil arranged to actuate switch means in the housing, the invention being characterized by a latch member connected between the electromagentic coil and the switching means, and by a bimetallic strip which may be in series with the electromagnetic coil or otherwise energised, the bimetallic strip being connected to hold the latch member against displacement by the electromagnetic coil until the bimetallic strip is heated, the latch member having means to actuate the switch means.
A preferred feature is a keeper fulcrumed to actuate the latch member and spring connected to be returned after pull from the electromagnetic coil, and also spring connected to the latch member to urge the end portion of the latch member against the keeper.
A further preferred feature is an arrangement of switch blades to be actuated by displacement of the latch member, but under control of the bimetallic strip which releases the latch member to move only when the bimetallic strip has been heated by current flow to the motor.
The device can be summarised as comprising an electromagentic coil to initiate the switching action by setting a keeper, and a bimetallic strip to prevent actual switching occurring until the bimetallic strip reaches a selected temperature.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan of the device with the cover removed,
FIG. 2 is a section of same on line 2--2 of FIG. 1,
FIG. 3 is a plan showing particularly the switching blades and contacts but with the case sectioned as on line 3--3 of FIG. 2, and
FIG. 4 is a schematic perspective view showing the interconnection between the keeper of the electromagnetic coil and the latch member, showing also how the bimetallic strip latches the keeper until the temperature of the strip reaches a required value.
DESCRIPTION OF THE ILLUSTRATED PREFERRED EMBODIMENT
The housing 1 has a cover 2 and has at one end an electromagnetic coil 3 and within the housing switch means and a bimetallic strip 5.
The electromagnetic coil 3 has a keeper 6 which is hingedly supported on the core 7 of the electromagnetic coil 3, the free end of the keeper 6 being urged away from the core by a return spring 8 when the coil is not energised.
Slidable within the housing 1 is a latch member 10 which is
REFERENCES:
patent: 1828299 (1931-10-01), Shuey
patent: 2376759 (1945-05-01), Dyer et al.
Broome Harold
Haug John A.
McAndrews James P.
Sharp Melvin
Texas Instruments Incorporated
LandOfFree
Motor starting device does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Motor starting device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Motor starting device will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-271552