Propeller fan induction motors for ventilating livestock buildings 3. Speed control characteristics
1988
Randall, J.M. | Elsayed, A.M. (AFRC Inst. Engineering Res., Wrest Park, Silsoe, Bedford MK45 4HS (UK))
Where the control of ventilation rate in livestock buildings is achieved by controlling the voltage to the fan motor to adjust its speed, it is necessary to understand the motor speed-control characteristics. These are evaluated for a number of fans commonly available in the UK. Sensitivity of control as shown by the speed/control voltage characteristic and stability of control as shown by the main winding current/control voltage characteristic are discussed. The merits of controlling the voltage to the main winding only whilst supplying the auxiliary winding at full voltage (3-wire control) are shown. Two wire control should not be used. Considerations in the use of transformer and triac speed controllers are outlined.
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