Motor starting relay device having PTC thermistors
AssigneeTDK Corporation
InventorsMichikazu Takeuchi, Hiroshi Nohara
Life of this patent
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Abstract
In a relay device, a first PTC thermistor has one end connected to a first external connecting terminal, and the other end connected to one end of a second PTC thermistor, the other end of which is connected to a second external connecting terminal, and the thermo-switch is thermally coupled to the first and second PTC thermistors, and connected in parallel with the second PTC thermistor. The thermo-switch is held closed when not heated, and is opened by heat generated by the first or second PTC thermistor. Therefore, the relay device is low in initial resistance, and small in power consumption during heat balance.
Claims12
A relay device for starting an electric motor, comprising:
- a first PTC thermistor, a first end of which is connected to a first external connecting terminal;
- a second PTC thermistor, a first end of which is connected to a second external connecting terminal and a second end of which is connected to a second end of said first PTC thermistor;
- and
- a thermo-switch being thermally coupled to said first and second PTC thermistors, and connected in parallel with said second PTC thermistor, said thermo-switch being closed when not heated, and being opened by heat generated by said first or second PTC thermistor.
A relay device for starting an electric motor comprising:
- a first PTC thermistor having a first terminal connected to an input terminal and having a second terminal, said first PTC thermistor having a first resistance;
- a second PTC thermistor having a first terminal connected to the second terminal of the first PTC thermistor and having a second terminal connected to an output terminal, said second PTC thermistor having a second resistance being higher than said first resistance;
- a thermo-switch being thermally coupled to said first and second PTC thermistors, and having a first terminal connected to the first terminal of the second PTC thermistor and having a second terminal connected to the output terminal;
- and
- said thermo-switch being closed during an initial start-up period of the electric motor for short-circuiting the second PTC thermistor and allowing current to flow through the first resistance of the first PTC thermistor with low resistance, and said thermo-switch being opened by heat generated in said first PTC thermistor during a steady-state of said electric motor for connecting the first PTC thermistor in series with the second PTC thermistor and reducing the current through the first PTC thermistor and reducing power consumed during a steady-state of the electric motor.
Dependencies are inferred from the claim text.