You asked: How do you control the speed of a universal motor?

Three methods of controlling the speed of a universal electric motor were discussed. These are the resistance control method, the field tapping method, and the centrifugal switch method. In the resistance control method, a variable resistance in series with the motor is used to set the RPM.

Can I put a variable speed control on any motor?

No. Some motors cannot change their speed at all – steppers, induction motors and synchronous motors. Some motors require different speed control techniques – brushless DC, and many others.

How does the speed of a universal motor can be controlled well to prevent damage to the motor?

In this method, the speed of the electric motor is controlled or set by connecting a variable resistance R in series with the motor. Due to having the resistance before the motor, the current to the motor is reduced, which in turns reduces the speed of the motor according to the setting of that variable resistance.

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What is the speed of universal motor?

Universal motors can be and are generally run at high speeds, 4000–16000 RPM, and can go over 20,000 RPM. By way of contrast, AC synchronous and squirrel cage induction motors cannot turn a shaft faster than allowed by the power line frequency. In countries with 60 Hz AC supply, this speed is limited to 3600 RPM.

How do you control the speed of a single phase AC motor?


The two primary ways to control the speed of a single-phase AC motor is to either change the frequency of the line voltage the motor sees or by changing the voltage seen by the motor, thereby changing the rotational speed of the motor.

How do you change the speed of a single phase AC motor?

Speed of Single phase motor can be controlled in different ways:

  1. Reducing voltage will reduce the speed within a range. Fan speeds are controlled this way.
  2. Change number of poles by altering winding connections.
  3. Change frequency of supply.

How do you change the direction of a universal motor?

The direction of rotation of a universal motor can be changed by either: (i) Reversing the field connection with respect to those of armature; or (ii) By using two field windings wound on the core in opposite directions so that the one connected in series with armature gives clockwise rotation, while the other in …

How do you change the direction of a hysteresis motor?

The direction of rotation of a hysteresis motor is reversed by the position of the shaded pole with respect to the main pole.

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How can you tell if a motor is universal?

Look for the stator core construction and rotor. If there is no commutator, then it is a AC motor. If there is a commutator and brushes, it may be either a DC motor or an AC commutator motor (Universal motor).

Can you put a speed control on a single phase motor?

Speed control of single-phase induction motors is desirable in most motor control applications since it not only provides variable speed but also reduces energy consumption and audible noise. Most single-phase induction motors are unidirectional, which means they are designed to rotate in one direction.

Can I use a dimmer switch to control AC motor speed?

No you can’t use a dimmer switch to control a DC motor. A dimmer uses diac and triac and only works with AC which commutates the triac OFF at the end of every half cycle.