I would be grateful for some advice on what is the most efficient way to speed control an exhaust fan?
Not knowing much about motors, it is a 240 volt unit 0.45 amps.
JD
Speed control of exhaust fan
Jul 13, 2006
6 Replies
"John Dunkley"
** A variac will likely work just fine.So might a phase control dimmer designed to control fan motors.
....... Phil
Electrical wholesaler will have plenty. Try this Clipsal one, but plenty of others.
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David
**Assuming the motor is a synchronous type, your chances are limited. PA's idea of a VariacT is ideal, but expensive and bulky. I know people who have put a lamp in parallel with the motor and used a standard light dimmer. I can't guarantee the results, but it should work. Another good way is to place the motor in series with a bridge rectifier (and the mains supply). Across the DC connections of the bridge, connect a MOSFET (suitable rated and heat sinked, of course) and vary the Gate Volts to get speed control that way. The advantage is the motor can be varied over a very wide range.
Trevor Wilson
www.rageaudio.com.au
"Trevor Wilson" wrote
Assuming the motor is a synchronous type, your chances are limited.
***** Wilson,you must be joking,an exhaust fan with a synchronous motor,the mind boggles!!!Brian Goldsmith.
All domestic mains powered exhaust fans I have ever seen use a simple shaded pole AC motor.
I think a synchronous motor would be a bit over the top for an exhaust fan :)
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**Call it a brain fart. Of course a standard induction motor will be the type used. My other comments and suggestions remain.
Trevor Wilson
www.rageaudio.com.au
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