Consistent speed control is critical for treadmill conveyor belts. When a person runs on a treadmill, their stride disturbs the motion of the belt. The runner's stride will be choppy if the motor driving the belt cannot quickly provide enough torque to overcome the disturbance. This problem is exacerbated when the user changes speeds as part of their exercise regime. If the belt does not smoothly accelerate or decelerate it seems like the treadmill is not operating correctly. In addition, at low speeds when a user steps on the belt, their weight can cause the belt to stop.
InstaSPIN-MOTION was applied to a commercial treadmill using a 4-HP, 220-V AC induction motor to drive the conveyor belt. The treadmill was tested across a variable speed range: 42 rpm at the low end to 3300 rpm at top speed.
The customer found that InstaSPIN-MOTION's advanced controller automatically compensated for disturbances, keeping the speed consistent while running and across changing speeds. The controller prevented the belt from stopping at low speeds when a load was applied. In addition, a single gain was used to control the entire operating range.