Erratic acceleration may make it necessary to check rotational feedback, but it does not by itself identify a faulty sensor. First, you need to know how the drive in the model obtains that information.
Three architectures that are not equivalent
Some motors use a tachogenerator; others include Hall sensors, and certain controls estimate rotation without an independent sensor that can be replaced as a separate part. The exploded view and schematic determine which one is present and whether it is supplied separately from the motor.
This component reports on motor movement. It should not be confused with a vibration sensor or with an equipment decision to limit the spin cycle because of other conditions.
Follow the signal to the control
- Identify the sensor, mounting, and intended connections.
- Check wiring and connectors using the power-off procedure.
- Compare the signal and its operating conditions according to technical documentation.
- Evaluate how it is received by the electronic module and whether the drive produces the requested movement.
Jerking, loss of acceleration, or a related code point to this check, but they can also accompany faults in the motor and its control. The meaning of the code depends on the manufacturer and model.
Test limitations
A measurement needs the conditions, terminals, and values specific to that circuit. Active signals and any live testing are for qualified personnel with the proper equipment. Do not swap terminals or test resistance values published for another family.
Before replacing the sensor, the diagnosis should distinguish between a true absence of signal, an open circuit in the wiring, and a reading failure in the control.