Fan Capacitor

[mwatsonxx]

A bull.

 

[Spooked]

To the op, take safety precautions, turn on the power, poke the fan blade with a screw driver, if it spins replace the capacitor. If it doesn't spin buy a new fan.

Now the drunken weekend tom foolery hijacking is over......................................
Do you mean the capacitor is like a starter motor?
If I spin the fan blades manually they will keep spinning if themotor is good?

 

[flameport]

Do you mean the capacitor is like a starter motor?
If I spin the fan blades manually they will keep spinning if themotor is good?

Some types of motors use capacitors for that purpose.
Others do not.

 

[JohnW2]

Some types of motors use capacitors for that purpose. Others do not.

Indeed - but, although I may be wrong, I would strongly suspect that the motor in a small bathroom extra fan would be one of those 'others'!

However, it does seem a rather odd idea to contemplate replacing a capacitor in a non-working fan on the basis that is the only component other than a motor which can be easily seen. I haven't yet noticed us being told whether it is or not but, as has been said, if it is a 'timer fan' then the timer board must surely be the prime suspect (unless the fan has just got 'stuck' as a result of muck)?

Kind Regards, John

 

[Jackrae]

That said, my daughter's Manrose failed due to the thermal trip deciding to go 'open circuit'. Out of curiosity I opened the motor up to reveal no sign of cooked windings, so I linked the trip out and the fan ran OK. It now resides in my workshop as a "supervised only" extractor for my cardboard box 'spray booth'

 

[Spooked]

I haven't yet noticed us being told whether it is or not but, as has been said, if it is a 'timer fan' then the timer board must surely be the prime suspect (unless the fan has just got 'stuck' as a result of muck)?

Hi John.
Post #1 has a link to the type of fan, no timer.
Post #5 explains that the fan blades spin freely and that there was no noise change before the fan stopped.

 

[JohnW2]

Hi John. Post #1 has a link to the type of fan, no timer. Post #5 explains that the fan blades spin freely and that there was no noise change before the fan stopped.

I confess that I didn't look at the link. However, I was aware that it spun freely and hadn't changed in sound, but worded my bit in brackets poorly - I should have written some like "(given that the fan has not just got 'stuck'....", rather than "(unless the fan has just got 'stuck' ...".

Since there's no timer, and no obvious mechanical problem, it does sound as if the motor is probably the culprit - although I suppose that it could also be the problem that Jackrae experienced ('spontaneous' failure of the 'thermal fuse' in the motor). As for the capacitor, I suppose it's not impossible, but, as I said before, I would personally doubt that the motor in such a fan would have a starter capacitor and, as has been said, if it's just a 'filter' capacitor, the fan should start without it (which yours doesn't).

Kind Regards, John

 

[Keir (Elec eng)]

The capacitor is a start assist capacitor. Not a suppression, power factor correction capacitor or anything else.
Pop in a 1uf replacement, it will work fine!
P.S if you manually rotate the impeller while the power is energised, it should begin to spin (at a slower speed) this will confirm a faulty cap and a good motor.

 

[Taylortwocities]

Four months in! I'd expect the OP has it fixed by now......

 

[Keir (Elec eng)]

Yes, but so many people on here misunderstand the function of a capacitor, I thought it best to clarify for any future readers of the thread.

 

[bernardgreen]

The capacitor is a start assist capacitor. Not a suppression, power factor correction capacitor or anything else.

It is more likely to be a run capacitor which provides a phase shifted voltage to a second motor winding. This shifted phase determines the direction of rotation and contributes a significant percentage of the magnetic torque applied to the rotor.

A start capacitor would require some form of disconnection for when the motor was running at normal speed. ( Centrifugal switch or timer )

 

[Keir (Elec eng)]

The following may be of use to some.
The OP of the thread required a capacitor rating of 0.82MAF

 

[bernardgreen]

The following may be of use to some.

Only to those whose fan has a compressor. It looks like a training video created by a company that produces appliances which have a compressor in the appliance

 

[Jackrae]

Must be one of the worst descriptions of start & run capacitors on the web

 

[securespark]

Every word will mean everything soon.

Goosed goosed goosed goosed, goosed goosed goosed goosed goosed goosed goosed goosed goosed!