Universal Motor; General Characteristics; Operating Principle; Motor Speed Control - Electrolux EWF1284EDW Service Manual

11.8 Universal motor

11.8.1 General characteristics

Collector motors are fitted on appliances with a spin speed of between 600 and 1,600 rpm.
1. Stator
2. Terminal board
3. Collector
4. Tachometric generator magnet
5. Tachometric generator coil
6. Brush

11.8.2 Operating principle

The stator winding is connected in series to the rotor winding (serial excitation).
Every section of the rotor winding is connected to a pair of collector blades (also referred to as a switching
device). The electrical contact between the collector and the fixed circuit is made by two static brushes on
the collector blades.
The motor rotation speed is in proportion to the supply voltage, supplied by an electronic control.
This type of motor is also referred to as "universal" because it can be powered by either alternating or
direct current.

11.8.2.1 Motor speed control


This is achieved by an electronic control varying the voltage (V) applied to the motor.
 The method adopted is the "phase partialization" command of the TRIAC. The TRIAC is an electronic
bidirectional switch. Closing of the circuit between A1-A2 (anodes) occurs when there are appropriate
starting pulses on gate (G).
Starting pulses
Voltage on the motor
Technical Support - MDM
0 V 110 V
56/97
180 V 230 V
599 76 11-68 Rev. 01