A measurement guide covering resolver excitation, Sin/Cos envelopes, shielding, mechanical alignment and software calibration.
A resolver reports rotor angle through two analogue feedback channels. The controller evaluates amplitude, the relative phase of Sin and Cos, their relationship to the excitation carrier and consistency with motor current.
Possible causes include wiring, shielding loss, mechanical misalignment or calibration error. Lissajous shape, channel amplitude and zero position help separate them.
A resistance check proves only basic continuity. Dynamic quality requires both channels to be viewed together and noise to be correlated with motor current or inverter switching.
After mechanical work, sensor alignment and the learned electrical offset must be considered together. A software reset cannot correct physical misalignment, and mechanical adjustment cannot conceal a wrong calibration.
Verification covers low speed, direction change, high torque and regeneration. Calculated angle must remain continuous and Sin/Cos amplitude balance must stay stable with temperature.