Final answer:
The RPM indication of a synchronous AC Motor-tachometer is governed by the frequency of the power supply, which is determined by the generator. The speed of the synchronous motor is directly proportional to the frequency supplied by the generator.
Step-by-step explanation:
The RPM indication of a synchronous AC Motor-tachometer is indeed governed by the generator. This is because in a synchronous AC motor, the rotational speed of the motor shaft is directly tied to the frequency of the electrical power supply, which is determined by the generator. The synchronous motor operates at a constant speed up to its full load. For example, an AC generator with a square armature coil having 200 turns and rotating at 3600 RPM will produce a specific frequency based on the number of rotations per minute. The generator's frequency can be calculated using the formula f = nP/120, where f is the frequency (in Hertz), n is the speed in RPM, and P is the number of poles in the generator.