An electric motor for driving a motor vehicle component, such as a fan motor for cooling cooling water, has a thermal fuse with a contact spring. The contact spring has attached ends that are connected to a conducting path section between which an interruption point is formed. The springy ends of the contact spring are in soldered contact with each other in a spring-biased manner. The thermal fuse is a fuse module with a plastic support in which the conducting path sections are partially embedded in such a way that the contact spring lies in a window opening in the support. Terminals of the conducting path sections protrude from the plastic support.

An electric motor for driving a motor vehicle component, such as a fan motor for cooling cooling water, has a thermal fuse with a contact spring. The contact spring has attached ends that are connected to a conducting path section between which an interruption point is formed. The springy ends of the contact spring are in soldered contact with each other in a spring-biased manner. The thermal fuse is a fuse module with a plastic support in which the conducting path sections are partially embedded in such a way that the contact spring lies in a window opening in the support. Terminals of the conducting path sections protrude from the plastic support.

A fuse component configured to provide overcurrent protection for an electric motor comprises a spiral fuse portion and a magnetic core. The spiral fuse portion encloses at least a part of the magnetic core, so that the fuse component is also configured to function as a choke of the electric motor.

A rotor assembly for a DC motor is provided which includes a rotor having a rotor shaft, a commutator mounted to the rotor shaft, and a varistor which is connected to the commutator via an electrically-conductive solderless fixing means, such as an electrically-conductive adhesive.

A rotor assembly for a DC motor is provided which includes a rotor having a rotor shaft, a commutator mounted to the rotor shaft, and a varistor which is connected to the commutator via an electrically-conductive solderless fixing means, such as an electrically-conductive adhesive.

A DC motor is configured so that, while either one of a pair of power feeding brushes makes contact with two commutator segments, the other makes contact with only one of two commutator segments. The DC motor is further provided with: a plurality of coils; a filter unit; and a calculation unit. The number of turns of a predetermined coil among the plurality of coils is different from the numbers of turns of the other coils. The filter unit allows the passing of the waveform of current generated on the basis of the fact that the numbers of turns are different from each other, and interrupts the waveform of current generated at the switching of the states of the contacts of the power feeding brushes to the commutator segments. The calculation unit calculates a rotational speed from the waveform passed through the filter unit.

A DC motor is configured so that, while either one of a pair of power feeding brushes makes contact with two commutator segments, the other makes contact with only one of two commutator segments. The DC motor is further provided with: a plurality of coils; a filter unit; and a calculation unit. The number of turns of a predetermined coil among the plurality of coils is different from the numbers of turns of the other coils. The filter unit allows the passing of the waveform of current generated on the basis of the fact that the numbers of turns are different from each other, and interrupts the waveform of current generated at the switching of the states of the contacts of the power feeding brushes to the commutator segments. The calculation unit calculates a rotational speed from the waveform passed through the filter unit.

A fuse component (36) configured to provide overcurrent protection for an electric motor (20) comprises a spiral (41) of a plurality of coaxial wire loops (44) and an outer insulating sleeve (39) surrounding at least a portion of the spiral (41). The overcurrent threshold of the fuse component (36) may be adjusted by changing the number of loops in the spiral (41) or the cross-section area of the wire in the spiral (41). The fuse component (41) may also function as an inductor (35) and/or connected to a speed adjustable resistor.

An electronic control unit includes two inverters, a magnetic sensor, a failure detection unit, an inverter driving unit, a signal examination unit, and a failed element identification unit. The magnetic sensor detects a magnetic flux generated around a winding. The failure detection unit detects an ON-state failure of the inverter. When the ON-state failure is detected, the inverter driving unit stops driving the inverter to which the ON-state failure has been detected, and continues driving the other inverter. The signal examination unit examines a presence or absence of a special signal. When there is a signal appearing according to a special magnetic flux, the failed element identification unit identifies a failed switching element based on a motor electric angle generated by the signal.

An electronic control unit includes two inverters, a magnetic sensor, a failure detection unit, an inverter driving unit, a signal examination unit, and a failed element identification unit. The magnetic sensor detects a magnetic flux generated around a winding. The failure detection unit detects an ON-state failure of the inverter. When the ON-state failure is detected, the inverter driving unit stops driving the inverter to which the ON-state failure has been detected, and continues driving the other inverter. The signal examination unit examines a presence or absence of a special signal. When there is a signal appearing according to a special magnetic flux, the failed element identification unit identifies a failed switching element based on a motor electric angle generated by the signal.