Motor start cap

The motor start cap on my chip collector seems to be a tiny bit dead. Anyone know where I can find something similar to a CD60 cap, 100 uF,

250V AC or better. Size wants to be something in the order of 35mm diameter and 80mm tall to fit in the bulge on the case.
Reply to
John Rumm
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Almost any electronic store, or a p[lace that really stocks spares for washing machines etc. etc.

Reply to
The Natural Philosopher

Well I just looked in Maplin, CPC, RS and Rapid, and could not find an exact match. RS had some that matched the spec, but were way to long to fit the case. I could probably get a 60uF that would fit, not sure how critical the actual capacitance is in this situation.

Reply to
John Rumm

When I needed one for my pressure washer, I went to a local motor rewind firm, and they sorted through their bin and found me a used - but good - one. It wasn't identical to the original one in size, but it fitted and works fine.

Reply to
Roger Mills

I'd second that. You can find them in most big towns.

Reply to
The Wanderer

In message , John Rumm writes

Umm... have you checked the windings?

I acquired a chip collector (2.2kW s/ph.) on the basis that the capacitor was duff but the motor might be OK. Trying it with a

*borrowed* capacitor was disappointing. It ran but very noisily.

After some investigation, I decided to buy a new 3ph motor for roughly the cost of re-winding the original. The suppliers kindly turned down the shaft for me as they had it disassembled to fit the flanged mount.

regards

Reply to
Tim Lamb

I'll third that - I had a similar problem with a 2kw motor from an old pressure cleaner that I was converting to drive my circular saw; blew the starter cap and got a replacement from the local rewind company. Rob

Reply to
robgraham

Yup, it runs ok if I give it a spin to get it started. I do have two doubts however. When disassembling it today I did notice that the stator winding had slight discolouration in a couple of places that suggests it might be getting hot. There was a binding string that was wrapped round the bundle of enamelled copper wire at the top, that looked like it may have been burnt through in a couple of locations.

The other one was I could not hear the centrifugal switch clicking out as the revs spun up or down. It seemed to move freely by hand however. I am sure in the past I used to hear it click in and out at at spin up and down.

This is a SIP twin bag jobbie with 1hp motor. Not that old - three years perhaps.

Reply to
John Rumm

100uF sounds quite high, are you sure that's right?
Reply to
geoff

In message , geoff writes

What are the physical dimensions ?

Reply to
geoff

The value directly relates to starting torque. It's not critical. Significantly lower value might cause problems if the motor expects to start with any load or any significant initial friction to overcome.

Reply to
Andrew Gabriel

Well it is what is written on the side of it:

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took some other piccies:

Where it lives:

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plate off:
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switch - open position:
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to be one of these:
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)

Closes easily with light pressure - electrical connection checks out ok when closed:

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switch - rest position
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position - reasonably firm push required, but it moves nice and freely once you overcome the spring force:
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string on one side of stator:
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the other side:
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Reply to
John Rumm

about 80mm tall (excluding wires which exit the top of the can directly without any tags), and 35mm diameter.

Reply to
John Rumm

I can find plenty of places selling 60uF devices...

Its only driving the impeller which is mounted directly on the motor shaft. The top and bottom ballraces mean the whole thing spins very freely - there is a inertia to overcome but little friction at low speed.

Reply to
John Rumm

That's got a 75uF start capacitor, for a 510W motor. That's probably OTT for starting the drill press which isn't going to have any significant starting load, but I suspect the motor is probably more general purpose and may also be used on machinary which does have a starting load. (Clarke do also sell just the motors.)

I had to replace the capacitor in my lawn mower a few years back. That's a 1200W or 1600W motor (can't recall), but I think the capacitor was a lot less than above, so you can't necessarily tell just from the motor power. (OTOH, I suspect that might be a run capacitor rather than just a start capacitor.) The capcitor died slowly in that case, it gradually got less and less starting torque (less able to start with any grass around the blade), and finally had to be started by hand (not brilliant for a lawn mower;-) and would happily run in either direction. When I got inside to the capacitor, it had spewed it's contents out (slowly I guess), which had set solid again as it cooled outside the case.

Reply to
Andrew Gabriel

This is 750W, but again not much starting load (although I expect the fan load becomes significant before the motor is to full speed).

Rather than trawl round too many shops I phoned SIP earlier and got them to direct me at an authorised spares place. Prolly cost a bit more that way (£14 inc delivery) but saves too much farting about.

These often seem to be smaller capacitance than the start ones.

Yes I can see that may have a H&S bod squirming ;-)

The case on mine looked a little worse for ware, and the inside of the housing was damp with what looked like leaked electrolyte, but no major show of guts! Having said that, it was showing diddly squat in the way of capacitance - a large wedge of DC series resistance you could see on a high ohms range, but 100uF it sure wasn't!

Reply to
John Rumm

Umm again:-)

It is a very long time since I knew anything about any of this but 100uF for a 1hp motor sounds excessive. The motor rewind people will know. AFAIR the start winding has more turns of a lower resistance than the main so may be apparent from the wire gauge.

Permanently connecting something designed for intermittent operation sounds like a cooking recipe. You can get enough speed to operate the switch by wrapping a few turns of string around the shaft and pulling. Disconnect first:-)

Age wasn't the issue. The previous owner had installed it out of sight and allowed the system to overfill: stalling the fan.

regards

Reply to
Tim Lamb

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