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US 11,606,008 B2Granted
EMI filter for DC motor
AssigneeJohnson Electric International AG
InventorBo Hu
Life of this patent
Estimating the term…
Abstract
An electromagnetic interference (EMI) filter 32 is provided which is suitable for a DC motor 10. The EMI filter 32 comprises an EMI suppression circuit 34 having first and second DC-motor-terminal inputs 36a, 36b, and an MW-band power choke 44 coupled to one of the first and second DC-motor-terminal inputs 36a, 36b to increase the motor inductance in the MW frequency band.
Claims13
A DC motor comprising:
- a first motor terminal, a second motor terminal and an electromagnetic interference (EMI) filter for a DC motor, the EMI filter comprising:
- an EMI suppression circuit having first and second DC-motor-terminal inputs;
- and
- first and second MW-band power chokes coupled to one of the first and second DC-motor-terminal inputs to increase the motor inductance in the MW frequency band;
- wherein the first and second DC-motor-terminal inputs are connected to the first and second motor terminals, and wherein the DC motor further includes a varistor connected to a commutator of the DC motor, each of the first and second terminals being in brushed communication with the commutator.
2 more elements
A method of suppressing MW-frequency-band emission of a DC motor, the method comprising the steps of:
- a] attaching an EMI suppression circuit having first and second DC-motor-terminal inputs to first and second motor terminals of the DC motor;
- b] coupling an MW-band power choke to one of the first and second DC-motor-terminal inputs of the EMI suppression circuit;
- and
- c] tuning an inductance of the MW-band power choke until a predetermined MW-frequency-band emission criterion of the DC motor is met;
- and the predetermined MW-frequency-band emission criterion is a CISPR 25, class 5 criterion in the MW frequency band.
2 more elements
Dependencies are inferred from the claim text.