# US 12,184,130 B2 · Motor

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- Number: US 12,184,130 B2
- Document ID: US12184130B2
- Status: Granted
- Kind: B2
- Application number: 18/046,938
- Filed: 2022-10-17
- Published: 2023-04-27
- Granted: 2024-12-31
- Earliest claimed: 2021-10-26
- Assignees: Nidec Corporation
- Applicants: Nidec Corporation
- Inventors: Tsuyoshi Yasumura
- Web page: https://patentgrep.com/patent/US12184130B2

## CPC

- H02K 7/14: Structural association with mechanical loads, e.g. with hand-held machine tools or fans (with fan or impeller for cooling the machine H02K9/06)
- H02K 11/40: Structural association with grounding devices
- H02K 5/06: Cast metal casings
- H02K 5/225: {Terminal boxes or connection arrangements (specially adapted for submersible motors H02K5/132)}
- H02K 11/0141: {Shields associated with casings, enclosures or brackets}
- H02K 11/25: Devices for sensing temperature, or actuated thereby
- H02K 11/27: Devices for sensing current, or actuated thereby (overcurrent protection responsive to temperature of the machines or parts thereof, e.g. windings, H02K11/25)
- H02K 11/33: Drive circuits, e.g. power electronics (H02K11/38 takes precedence)
- H02P 29/027: {the fault being an over-current}
- H02P 29/032: Preventing damage to the motor, e.g. setting individual current limits for different drive conditions
- H02K 2211/03: Machines characterised by circuit boards, e.g. pcb
- H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53})
- H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS

## Abstract

A motor includes a motor control circuit having a ground terminal, and a current limiting part disposed on a path electrically connecting the ground terminal and an external ground terminal included in an external circuit disposed outside the motor.

## Claims

### Claim 1

A motor comprising:
a motor control circuit having a ground terminal; and
a current limiting part disposed on a path electrically connecting the ground terminal and an external ground terminal included in an external circuit disposed outside the motor.

### Claim 2 (depends on 1)

The motor according to claim 1, further comprising a stator and a rotor radially opposed to the stator, wherein
the stator includes a metal housing that covers a part of the stator, and
the metal housing is disposed on the path.

### Claim 3 (depends on 2)

The motor according to claim 2, wherein
the part of the stator is electrically connected to the metal housing, and
the motor further comprises a ferrite bead disposed on a path between the metal housing and the ground terminal.

### Claim 4 (depends on 2)

The motor according to claim 2, wherein
the housing is electrically connectable to a metal member disposed outside the motor, and
the metal member is electrically connectable to the external ground terminal and an application end of a ground potential.

### Claim 5 (depends on 3)

The motor according to claim 3, wherein
the current limiting part is a PTC thermistor,
the stator includes a coil,
the motor further comprises a board on which the motor control circuit and the current limiting part are provided, and
the current limiting part is disposed on a surface of the board on a side opposite to a coil side.

### Claim 6 (depends on 1)

The motor according to claim 1, wherein the current limiting part is a PTC thermistor.

### Claim 7 (depends on 1)

The motor according to claim 1, further comprising:
a switch element as the current limiting part;
an overcurrent detector that detects an overcurrent flowing through the switch element; and
a switch controller that turns off the switch element when the overcurrent is detected by the overcurrent detector.

### Claim 8 (depends on 1)

The motor according to claim 1, wherein the current limiting part is a positive thermal coefficient (PTC) thermistor.

### Claim 9 (depends on 1)

The motor according to claim 1, wherein the current limiting part is on a same board as the motor control circuit.

### Claim 10

A motor comprising:
a motor control circuit having a ground terminal;
a current limiting part disposed on a path electrically connecting the ground terminal and an external ground terminal included in an external circuit disposed outside the motor;
a stator and a rotor radially opposed to the stator, wherein
the stator includes a metal housing that covers a part of the stator, and
the metal housing is disposed on the path, wherein
the part of the stator is electrically connected to the metal housing, and
the motor further comprises a ferrite bead disposed on a path between the metal housing and the ground terminal;
a stop command determination circuit that determines presence or absence of a rotation stop command for the rotor; and
a switch element as the current limiting part that is controlled to be turned on and off by the stop command determination circuit.