This wall mounted experimental unit consists of one stationary and rotary plates. Lower stationary plate is attached to the aluminium wall bracket. Top rotary plate rotates on a shaft fitted with ball bearing but the plate remains in contact with the friction plate at all times.

Friction discs are placed between the stationary and rotary aluminium plates. Contact pressure depends upon the weight added to the rotary plate alongwith the mass of the plate itself. Torque is applied to the rotary plate through two loaded cords and pulleys. The cords wrap around a groove in the upper plate.

Calibrated weights are also supplied which enable the loading force to be varied and applied torque to be adjusted also.