Fans slow to start

[JHZR2]

Home pedestal fans. Both around 12 or 14" I think. One white-Westinghouse from 2000, one allaire from 2007. both just start really slow, if they start at all on low,

Both will start ok on high, slower than usual, but will start, and after a bit will run on low, until they are stopped and sit stationary for a while.

Thoughts on if this is a lube or a capacitor issue? I haven't taken anything apart yet, if I even can.

Thanks!

 

[cchase]

Not sure but I have a small fan that does the same thing, and when I took it apart and lubricated everything it didn't change anything.

 

[ls1mike]

Sounds like lube issue, they generally only use the caps to start

 

[HTSS_TR]

My 30+ years old floor fan was similar for the last 4-5 years. I lubed it ATF and it works well for summer months. Finally it died last week, when I tried to turn it on I can hear the sound from the fan but the fan didn't turn at all.

 

[JHZR2]

Originally Posted By: ls1mike
Sounds like lube issue, they generally only use the caps to start


Right and the issue is at the start. A bad cap wouldnt support the necessary inrush current to get the fan moving and thus not enough torque to get going... Was my thought...

 

[Hokiefyd]

I posted a similar inquiry a few months ago about a Vornado fan I have. The issue with mine is/was a sticky front motor bearing. If you take the front of the fan guard off, you can spin the blade back and forth by hand. Feel for resistance (it should spin very free). If it spins free, it's probably some type of an electrical issue. If it turns with resistance, you can be sure of a lubrication problem.

 

[JHZR2]

So I opened up my fan tonight to see about a repair.

The shaft spins with just the slightest starting torque to overcome, then it spins smooth and free. It's smooth with the oscillating function engaged or decoupled.

I tried to test the capacitor. Using my fluke meter, I checked resistance (318 Ohm), and then tried the capacitor testing feature but could not get a reading.

So the cap isn't short, but I don't have another to compare it to either.

What about lubing? There aren't service lube ports like on the old fans, so what's the best approach?

Should I take the four screws that hold the motor together out and break it all apart to lube?

I could use ATF, 3 in 1 electric motor or a light turbine lube.

Thanks!

 

[JHZR2]

Did one other test. Fan is 120V, and putting meter on the two leads of the cap with the fluke 179, I saw 222VAC.

Checking the white lead to the case, I got 49V, and the grey lead to the case, I got 104V.

There definitely is some sound from the front bearing, though it spins smooth. It will occasionally groan or whine when running (not loaded since the blades are off), never noticed that when the blades were on...

 

[cchase]

Glad to see you are tearing into this job.

I'd probably leave the motor together and put a few drops of oil on the bearing while spinning the armature by hand. Or, that's what I've done in the past with good results.

 

[Propflux01]

Almost sounds like the Cap has opened up. I would lube up the sleeve bearings and try it again. if it is still the same, replace the cap.

 

[JHZR2]

Originally Posted By: Propflux01
Almost sounds like the Cap has opened up. I would lube up the sleeve bearings and try it again. if it is still the same, replace the cap.


Its not open, there is definitely AC going through and it has connectivity... Though 300 Ohm is awful high for a capacitor, I think, especially if it is sourcing starting current rather than power filtering.

If I replace, what is the best source? Radio Shack?

What lube should I use?

 

[Quest]

lube the bushings from each end (of the shaft). I don't care about what they say, for I've used from AW32 lube to all-in-1 sae20 (my fave) and they all worked fine and no gumming so far.

Also: for that film cap: replace it with a fresh new one from ePrey or similar: just look under "motor run cap" and refine your search looking specifically for film type (polypropylene film).

BTW: don't look for motor run film caps from rat shack for they don't carry the correct type. Using incorrect type may lead to short circuits (and fire hazards).

Q.

 

[Propflux01]

That is why I think under electrical loading it might be open or opening.

As for lube, what Quest said works just fine. Most of those motors are sintered bearing types, and will absorb most any type of half-way liquid lube.

 

[Dave Sherman]

If you disconnected the capacitor wires and measured 318 ohms, it has failed. You might briefly measure some resistance using an ohmmeter, but once it has charged it should be a nearly infinite resistance.

Edit: If you just put the ohmmeter wires across the capacitor without disconnecting one of the wires first, that 318 ohms is most likely the motor windings you are measuring. Not going to tell you anything about the capacitor.

 

[GeaugaFletcher]

Dave's right about the meter work. You'd need to desolder the cap or otherwise take it out of the circuit to do any good measurements on it.

Off hand, I'd say it's a lube issue / mechanical.

 

[JHZR2]

Yeah I thought having it off would create an open circuit, but I suppose there would be line capacitance that the meter will pick up.

Time to unsolder.

Thanks!

 

[JHZR2]

Haven't messed with the cap, but lubed the an up, and while it spun(by hand) freely before, it spins better now. I used what I believe to be unocal 76 iso 32 turbine oil in a zoom spout oiler.

One other fan we have, much newer and far fewer hours on it, is also slow to start, but it varies speed once going. You hear it speed up and slow down. Ideas on it? I'll take it apart next.

 

[Quest]

replace the film cap first if I were you. Afterall: it's a motor run cap that makes the voltage lag the current by almost 90degrees (to be precise: I believe the phase difference of Im and Is is about 80degrees, given my ailing memory). This is to give single-phase motor a higher torque "kick" spin to start it up. When the film caps is bad: you don't have enough of that torque "kick" to start the rotor...thus the slow starting or even humming of the motor as it gradually spins up.

Oh and of course: a "sticky" motor shaft bushing will make this starting up more "challenging" than ever...

As to the variation of speed, it's hard to tell what goes wrong with it w/o knowing what kind of motor design it is.

Q.