The apparatus consists of a rotor mounted in bearings. This rotor is free to rotate about.
Its own axis i.e. axis of spin.
Axis of precession.
Axis of gyroscopic couple.
The rotor is connected to the variable speed motor. The weight of the motor is balanced by another weight, which is on either side of the rotor. By putting weights on the weight platform torque can be supplied to rotor, which is also called gyroscopic couple.