In the past, reversible three-phase motor-driven tools such as a drill press with 1 hp (0.75 kW) or less used the drum rotary switch. ... The single-phase control shown will not reverse even if the control is thrown over to reverse position while running. ... This circuit diagram is also shown in full detail rather than partial form because of its widespread application. ... When the forward contactor pulls in, the normally open maintaining contacts 3 and 2 are closed to hold the forward function.
|Title||:||Handbook of Rotating Electric Machinery|
|Author||:||Donald V. Richardson|