| Abstract |
Solid state soft starters based on triacs or SCR's are often used to lower the starting current of three phase motors. Consequently, also the starting torque will decrease. However, for single phase motors, more particulary permanent-split capacitor motors, often an increased starting torque is desired. In this paper a quite surprising solution is presented. A triac in series with the capacitor can improve the starting torque considerably. The circuit turns out to be competitive with a two value capacitor circuit. The same principle can also be applied to three phase motors in steinmetz configuration, yielding similar improvements. |
