changing the load
changing the supply voltage
changing frequency
using brakes
Answer is Wrong!
Answer is Right!
The correct answer is C. changing frequency.
A synchronous motor is an AC electric motor in which the rotor turns at a constant speed synchronous with the AC electric power supply frequency. The speed of a synchronous motor can be changed by changing the frequency of the AC power supply. This can be done by using a variable frequency drive (VFD). A VFD is a device that converts AC power to DC power, and then back to AC power at a different frequency.
The other options are incorrect because:
- Changing the load will not change the operating speed of a synchronous motor. The load only affects the torque that the motor produces.
- Changing the supply voltage will not change the operating speed of a synchronous motor. The supply voltage only affects the current that the motor draws.
- Using brakes will not change the operating speed of a synchronous motor. Brakes only affect the speed at which the motor comes to a stop.