Patent ID: 11888357
Assignee: NIDEC MOTOR CORPORATION
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A method for mounting a calibrated encoder assembly to an electric motor so that a sensor output signal waveform produced by the calibrated encoder assembly is aligned with a back electromotive force (BEMF) waveform of the electric motor, said method comprising:
coupling the electric motor to a servo driven functional tester;
fixing the calibrated encoder assembly to an alignment plate;
coupling the alignment plate to the electric motor;
rotating the electric motor using the servo driven functional tester;
measuring the BEMF waveform of the electric motor using a data acquisition unit;
measuring the sensor output signal waveform;
adjusting an orientation of the alignment plate relative to the electric motor to align the sensor output signal waveform to the BEMF waveform within a predetermined measurement range; and
securing the alignment plate to the electric motor in the adjusted orientation,
wherein measuring the BEMF waveform of the electric motor comprises measuring the BEMF of each of three phases of the electric motor, the electric motor being a three-phase electric motor, the three respective phases including a U phase waveform, a V phase waveform, and a W phase waveform,
the sensor output signal waveform comprising a sine output signal waveform and a cosine output signal waveform, wherein adjusting an orientation of the alignment plate relative to the electric motor comprises:
rotating the alignment plate until an ideal “zero” position of the electric motor and an ideal “zero” position of the calibrated encoder assembly occur relative to each other within a predetermined threshold range, the ideal “zero” position of the electric motor being defined at an instance when a falling edge of the U phase waveform crosses zero, the ideal “zero” position of the calibrated encoder assembly being defined at an instance when a rising edge of the sine output signal waveform crosses zero.