Protector means for electric motor

• US 4,207,602 A
• Filed: 10/30/1978
• Issued: 06/10/1980
• Est. Priority Date: 10/30/1978
• Status: Expired due to Term

• Current Assignee: Gould, Inc. (Transdigm Group Incorporated)
• Original Assignee: Gould, Inc. (Transdigm Group Incorporated)
• Inventors: Heberlein, G. Erich Jr., Kussy, Frank W., Haydu, John L.
• Primary Examiner(s): Salce, Patrick R.
• Application Number:
  US05/955,887
• Time in Patent Office: 589 Days
• Field of Search: 361/24, 361/25, 361/26, 361/27, 361/32, 361/31, 361/105, 361/103, 361/106, 361/37, 361/23, 318/471, 318/473, 318/474, 318/783, 318/782
• US Class Current: 361/24
• CPC Class Codes: H02H 7/085 against excessive load H02H6/00 takes precedence
• CPC Class Codes: H02H 7/0852 directly responsive to abnormal temperature by using a temperature sensor in a control circuit H02H7/0833

Abstract

A three phase motor is constructed with each of the three phase windings thereof split in half so that the motor may be selectively connected for energization from either a relatively high or relatively low source. Motor protectors are provided in the form of a three pole automatic resetting overload relay means and two thermostatic switches. The heaters for the individual poles of the overload relay means are connected in series with a half section of the individual phase windings and do not have to be changed when either high or low voltage energization is selected for the motor. The thermostatic switches are embedded in two of the other three winding sections but electrically insulated from the motor winding. The control contact means of the overload relay means and the thermostatic switches are connected in series with the energizing coil of the electromagnet for the contact through which the motor is connected to its energizing source.

Claims

1. A three phase motor and protector means therefor;

said motor including first, second and third phase windings each comprising a first and a second section, said sections of said phase windings being connectible in a first wye-circuit array for energizing said motor from a relatively low voltage source and also being connectible in a second wye-circuit array for energizing said motor from a relatively high voltage source having approximately twice the voltage of said low voltage source;

said protector means including first, second and third overload relay heaters connected in electrical series with the respective said second section of said first phase winding, said first section of said second phase winding and said second section of said third phase winding;

contact means operatively associated with said heaters and being connected in a control circuit having an operating coil of an electromagnetic contactor through which said motor is energized;

in said first array said first section of first phase winding being connected from the center of the wye to a first energizing phase and being in parallel with the series combination of said first heater and said second section of said first phase winding, said second section of said second phase winding being connected from the center of the wye to a second energizing phase and being in parallel with the series combination of said second heater and said first section of said second phase winding, and said first section of said third phase winding being connected from the center of the wye to a third energizing phase and being in parallel with the series combination of said heater and said second section of said third phase winding;

in said second array said first heater being in series with said first and second sections of said first phase winding between the center of the wye and a first energizing phase, said second heater being in series with said first and second sections of said second phase winding between the center of the wye and a second energizing phase, and said third heater being in series with said first and second sections of said third phase winding between the center of the wye and a third energizing phase;

said protector means also including thermostatic switch means including switching means in circuit with said contact means and temperature sensing means for operating said switch means responsive to temperature of said motor detected by said sensing means.

2. A three phase motor and protector means therefor as set forth in claim 1 in which the temperature sensing means is operatively connected to at least two of said phase windings.

3. A three phase motor and protector means therefor as set forth in claim 2 in which the temperature sensing means is imbedded in and electrically insulated from said phase windings.

4. A three phase motor and protector means therefor as set forth in claim 1 in which said temperature sensing means includes a first and a second portion operatively connected to the first section of said first phase winding and the second section of the second phase winding, respectively.

5. A three phase motor and protector means therefor as set forth in claim 1 in which the heaters are portions of overload relay means constructed for automatic resetting upon cooling of said heaters to a predetermined temperature.

6. A three phase motor and protector means therefor as set forth in claim 5 in which the thermostatic switch means resets automatically when the temperature sensed by said sensing means falls below a predetermined level.

7. A three phase motor and protector means therefor as set forth in claim 1 in which the temperature sensing means includes portions operatively connected only to said first section of said first phase winding and to said second section of said second phase winding.