When the excitation current is suddenly turned into the beginning so that the value of 50% and no residual arising from the rotor rotation will cause the output torque generated magnetic fluctuations. Effectively prevent or eliminate the residual magnetic force method is to reduce the current in the rotor rotating at the same time.

The relationship between tension and torque: M= F●R
F: Tension N (Newton)
R: materials, roll radius m (m)
M: torqueN●m(N●m)
Where in the winding process is often necessary to use tension control, this time of the wire, strip the actual tension, that is, from the above formula to determine.

Slip power: P=M●n/9.55=F●V 
P: slip differential power W (W)
n: the actual slip rpm (rev / min)
M: transfer torque N●m (N●m)
F: Tension N (Newton)
V: Belt speed m/s(m/s)

Hysteresis brakes work process, the consumption of power doing work, into heat. With a rated power to allow slip. More than the device will overheat damage.