Hi People
I have a pair of 240VAC, single phase, 125mA cooling fans that I wish to use in a window above my workbench as exhaust fans.
Now, run singly on 240V, they are quite noisy, and I wondered what I could do to cut their speed down a tad. I thought of a power resistor, to cut the voltage, and thus increase the slip, but then it would surely be more efficient to wire these two in series. That would halve the current to 62.5mA and slow them surely, but if there is too much slip, are they not likely to heat up and let out the sacred smoke? I suppose the way to go is to try, but if someone could shed a bit of light I would be grateful.
One thing I'm unsure of is the voltage drop across each motor, compared with the voltage drop across just one. Am I right in assuming that zero voltage drop implies infinite current (theoretically)? And 240V drop implies infinite resistance? Perhaps this can't be calculated and must be measured?
Cheers, Jack
Sent from my iPad
I have a pair of 240VAC, single phase, 125mA cooling fans that I wish to use in a window above my workbench as exhaust fans.
Now, run singly on 240V, they are quite noisy, and I wondered what I could do to cut their speed down a tad. I thought of a power resistor, to cut the voltage, and thus increase the slip, but then it would surely be more efficient to wire these two in series. That would halve the current to 62.5mA and slow them surely, but if there is too much slip, are they not likely to heat up and let out the sacred smoke? I suppose the way to go is to try, but if someone could shed a bit of light I would be grateful.
One thing I'm unsure of is the voltage drop across each motor, compared with the voltage drop across just one. Am I right in assuming that zero voltage drop implies infinite current (theoretically)? And 240V drop implies infinite resistance? Perhaps this can't be calculated and must be measured?
Cheers, Jack
Sent from my iPad