Can't find a source for replacement motor run capacitor, size is the problem

I have a linear actuator in which the motor run capacitor has failed.

It's one manufactured by ICAR, marked as follows:-

4 microfarad ECOFILL WB40 400 V B 10.000 h 450 V C 3.000 h Wire connections (though tags would be OK)

It's 51mm long and 25mm diameter and can't be any bigger at all because there's a round space that matches its size perfectly in the actuator. Tags instead of wires would be possible but no increase in size is possible. Capacitors with a stud sticking out of the end (which a lot of motor run capacitors have) won't fit.

There's no obvious distributor for ICAR motor start capacitors in the UK, I've tried asking them directly but while they did at least reply they couldn't really help for a one off.

There are *lots* of 4 microfarad 450 volt capacitors to be found but all the ones I can find are fatter and/or longer than I need. Even CPC and Farnell have let me down.

Reply to
cl
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Can you confirm something like:

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won't fit if you remove the stud?

Otherwise the Ducati 4-16-18 4uF cap seems about right, but that range has fewer suppliers.

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Reply to
Fredxxx

Yes, you're right, the 4.16.18 series is the right size as long as cutting the stud off is OK, it looks as if it's just a plastic stud continuation of the case.

Thanks.

Reply to
cl

Ah, oops, no. The Ducati 4-16-18 capacitor is only 250 volt at 10000 hours. It is rated to 425 volts (1000 hours) but it's getting a bit near the bone. The existing one is 3000 hours at 450 volts.

Reply to
cl

Something like:

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is listed as 28 diameter, and 56 long. I was hoping that length might include the stud, but having just checked the 16uF one I bought recently that was quoted at 70mm long, it does not appear to.

Reply to
John Rumm

How many hours is this motor going to run?

I agree the 4-16-10 series is more rugged.

The height dimension is the size of the body and doesn't include the stud.

Reply to
Fredxxx

Yes, there's *loads* that size, that won't fit. :-(

Reply to
cl

Just noticed that Rapidonline do ICAR motor caps - alas only the ali can versions by the looks of it. It might be worth asking them if they could order you what you need.

Reply to
John Rumm

snipped-for-privacy@isbd.net wrote in news: snipped-for-privacy@esprimo.zbmc.eu:

Why are motors so particular about the value of the capacitor? Why haven't they been rationalised?

Reply to
DerbyBorn

I suspect it's down to optimising starting characteristics required for different applications, and reducing costs where possible.

Reply to
Fredxxx

They aren't. A lower value one would work, providing the motor is not operating near the limit of its starting or running torque. However, it would be very bad if one was chosen which didn't generate quite enough torque to start the motor - it could burn out the motor if left energised for some time with a stalled rotor.

I've no idea what the load characteristics of this application is.

What? Motors?

Reply to
Andrew Gabriel

Just cut the stud off

NT

Reply to
meow2222

If this cap is fitted in a sheet metal cover fitted to the motor, can you make a slightly bigger cover?

Reply to
F Murtz

If all else fails perhaps you could fit the next capacity down, and add a physically small cap elsewehre to provide the remaining capacitance.

NT

Reply to
meow2222

No, it's in a rectangular case with the capacitor in a tight fitting moulded section. It's not really modifiable, though I guess I could fit the capacitor externally, that would involve running some extra wires.

Reply to
cl

They don't change size with capacity except in very big steps. To get a physically smaller capacitor you'd probably have to go down to 1uF.

Reply to
cl

You're pretty stuck then.

NT

Reply to
meow2222

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