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5.8.2.1 Control of the speed of the motor
Speed control is obtained by using an electronic control system to vary the voltage (V) applied to the
motor.
The technique used consists of a "phase division" performed by the Triac. A Triac is a bi-directional
electronic switch. Closure of the circuit between A1 and A2 (anodes) takes place in the presence of the
appropriate signals received by the gate (G).
5.8.2.2 Direction of motor rotation
The direction of rotation of the motor depends on the way in which the rotor and stator are connected
together. This connection is performed by two of the timer contacts or by the relays on the PCB.
Clockwise rotation
Counter-clockwise rotation
EC Electronic
control
system
P Motor
overload
cut-out
S Stator
M Rotor
T Tachometric
generator
TY Triac
R1,2 Reversal relay
Start-up signals
Voltage to motor