Electrical Projects Basically, a universal motor is nothing more than a dc motor with a series field. However, the motor has been designed so that when alternating current is applied to the motor, the magnetic fields from the armature and the field windings cause the armature to turn. So a universal motor is one which can be operated from either ac or dc with nearly the same output characteristics from the motor.

Because they are so like series-wound dc motors, universal motors have high speed characteristics, but their speed is sharply affected by the amount of load on the motor. A resistor may also be inserted in series with the armature and the field windings to help control the speed of the motor.

Universal motors can be built very cheaply; for this reason, plus the fact that they can be operated on either ac or dc, they are used extensively in many small appliances, including adding machines, electric fans, portable hand-tools, electric shavers, and een movie projectors—in short, you may find a universal motor in nearly any small home appliance.

October 6, 2008