Dodgy capacitor or motor?

[vwmark]

Hi. Frustrating day.

Took the day of work to finally get the mill i bought over a year ago running and in place.

Its a Pallas V1 with 2.8hp single phase motor. Bought with blown start cap. Extracted motor and changed cap (200mfd) and it ran great on the bench.

After a load of faffing getting it back in place, started it up and it was a bit slow. Stopped, pulled clutch in and it ran ok. Let clutch out and it ran ok for about a minute until start cap started smoking badly.

Now have I bought a dodgy cap or do i have a motor problem blowing cap? Mill has not been used for yeats but everything moves freely.

Not happy wasting a precious holiday!

Whats everyones thoughts?

 

[dobbslc]

Can you get the end cover off the motor? Have look to see if the centrifugal switch is working, it should move in and out and that's what turns off the start cap when it's up to speed.
Make sure the mill is free to turn as if something is seized or just tight the motor won't be able to get up to speed and it'll stay running on the start cap.

 

[vwmark]

Nothing seized. Just surprised how quick capacitor got hot. Will have to strip it again to get motor out.

 

[GW8IZR]

Can you get the end cover off the motor? Have look to see if the centrifugal switch is working, it should move in and out and that's what turns off the start cap when it's up to speed.
Make sure the mill is free to turn as if something is seized or just tight the motor won't be able to get up to speed and it'll stay running on the start cap.

+1 most likely candidate,

I'd also check how its been wired. did you just copy where the wires came from or follow the diagram/layout (assuming there is one, often in the terminal box)

maybe its configured wrongly which is why the original c failed, worth checking anyway

 

[WorkshopChris]

As above, if its working as normal.
You can normally hear a centrifugal switch click as the motor slows down once turned off.

 

[arther dailey]

All the above makes sence, but as you bought it with a blown cap is there a possability that cap was not the original? so maybes wrong value.
I would as suggested double check machine is not partially siezed, also it could be motor isnt "man" enough as single phase do not have same power characteristics as 3 phase.thats presuming it was a 3 phase machine?Arther

 

[brightspark]

it will run on a 3 quarter hp single phase motor . I have one on mine

 

[arther dailey]

hmmm, somethings amiss then.....

 

[vwmark]

It could be that the cap was wrong but it looked original - same make as the run caps. Ran ok on the bench so maybe it is the switch stuck. Its only been used 3 times in 30 years! When I got the motor out is was a bit dusty but looked a fairly "new" motor. I though the original cap had blown as they have a habit of absorbing water.

Will get another cap and check the switch. Just a pain in the .... getting the motor out as the last owner made a clutch that lifts the motor up, disconnecting drive. Works great but sits in the way of the motor.

 

[vwmark]

Cheesed off. Spent an hour stripping motor out. Fitted new cap. Motor started slow and blew new cap. Stripped motor and no centrifugal switch but burnt windings. Start cap seems to be controlled by a small coil.

Is it worth getting the motor repaired or try and find a used 2-3hp single phase motor?

What do you all think?

 

[Omniata]

New will probably be cheaper in terms of time, unless you know a cheap quick rewinder?
Are all the other electronics sound?

 

[daleyd]

Is that a true single phase motor or a 3 phase that's had a capacitor slung across it to make it run on single phase? (Just looking at the connector block I've only seen that type on a 3 phase motor before, but it could well have been a lash up of bits)

 

[vwmark]

The plate says single phase but looks like a manufacture lash up. How much is it to get a motor wound?

 

[arther dailey]

yup thats burnt out, there is no such thing as a "cheap" re winder, look for another mtr would be my advice,dont throw good monies after bad.would be interesting to see the name/data plate on that mtr.Arther

 

[brightspark]

the only time motors are worth getting rewound is if there special or unobtainable

 

[Exuptoy]

IIRC any motor under something like 2 or 3HP was cheaper buying new than rewinding. At least that was what we were told when it was costed up against new by the local rewind place a few years ago.

 

[vwmark]

yup thats burnt out, there is no such thing as a "cheap" re winder, look for another mtr would be my advice,dont throw good monies after bad.would be interesting to see the name/data plate on that mtr.Arther

 

[arther dailey]

somebody had mention was a conversion attempted from a 3 phase mtr, looking at windings single phase,plate confirms this. Reckon it was probably start windings burnt out when you got it, hence slow rotation and lack of power/speed.
best bet replace with new/good second hand, could place wanted ad. on here? Arther