AC SINGLE PHASE MOTORS

A/C SINGLE PHASE

Single phase induction motors are not self starting. The single winding of single phase motor will not produced a rotating field by itself and some arrangement is required to turn the alternating field which it produced into rotating field. By providing a second winding (Auxiliary winding)on the stator and to alter the phase of the current in the second winding, thus making it similar to a two phase motor. The phases displacement may be obtained by connecting a capacitance in serial with the starting winding or shunting one winding by resistance and another by an inductance.

CAPACITOR START MOTOR

Instead of using inductance or resistance of giving necessary phase displacement in the starting winding, a capacitor is used. The connection diagram shown in the fig. this motor has high torque.

     
   Uses: Lathe, Fan Blower, Pumps, etc

PERMANENT CAPACITOR MOTOR

In this type there is no centrifugal switch. The capacitor remains permanently in series in starting and running condition.

Uses: Ceiling fan,Table fan and where low torque is required.

              
UNIVERSAL MOTOR

This motor is designed to work on both AC and DC supply.In the universal motor stator winding is in series with motor winding.

The stator is built up of laminations instead of a solid piece as in DC series motor. When working on AC the armature and field current have the same direction with respect to each other. Hence the motor works like an ordinary series motor. The speed is above synchronous speed and  blow the dangerous valve where as working on AC. The load speed characteristic is similar to that of a DC series motor.

Uses of Universal Motors: Portable drilling machine, Hairdressers, Blowers, Sewing   machines etc.

SAFETY OF HAND TOOLS

             
Mostly all hand tools are high speed motors and Universal Motors. Earthing the machine is more important and the plug and sockets used should have sufficient current rating. The flexible cable used for extension should not be more than 15 Mtr. All equipments should have double insulated winding. The socket supply source have a ELCB (Earth Leakage Circuit Breaker) 0.03A protection