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Motor question. Sigh.

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Motor question. Sigh.

Postby PeterBassett » 02 Jun 2016, 17:21

Bob of this parish, may I ask for some advice please?

I've been building a cyclone extractor and have just today got it all together and working.

The donor unit was a charnwood single phase 3hp extractor.

I've ran it in the garage for a few seconds several times to see it working.

I have a 16amp feed for it in the garage off a type c breaker. The line to the house is 6mm armored I believe.

Today I finally get it all together and run it for about five minutes sucking up all the saw dust collected in the shop, worked a treat! I sucked up a strip of paper and that ended up in the impeller so I stopped it. Gave it time to wind down and started it up again, this cleared the paper but the motor stopped running.

I press the go button and the motor starts but doesn't run. I have tried, twice, holding the start button down and it does get up to speed. The moment I let go, it stops again.

It isnt making any bad noises that I can tell. When it slows down I hear a definite loud click from the centrifugal switch.

The motor body is warmish to the touch but not at all what I would call hot.

I ran a multimeter to the ring main and it is reading 230v. I did the same to the motor and at had trouble getting a startup voltage but it very quickly came up to 230v.

I'm beginning to suspect the starter.

Anyone's opinions on the matter would be gratefully received.

Pete
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Re: Motor question. Sigh.

Postby PeterBassett » 02 Jun 2016, 18:00

Further to this, I've had a look at the starter cap and it appear to be ok. No bulging.

Image

My multimeter won't to capacitance unfortunately.

Thanks again.
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Re: Motor question. Sigh.

Postby old » 02 Jun 2016, 18:13

Is it a no volt starter, which in effect is a relay coil across the supply with a contact in the supply feed. pressing the contact connects the supply that then holds up till supply is lost.so it could be the coil open circuit but check for lots of dust just in case.
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Re: Motor question. Sigh.

Postby PeterBassett » 02 Jun 2016, 18:46

This is the starter.

Image
Image
Image

Its relatively clean and I had it open previously to move the starter away from the motor body. It has only started the once since the move however.
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Re: Motor question. Sigh.

Postby DaveL » 02 Jun 2016, 19:31

It does sound like the starter is not holding the contacts closed. A possible test would be to disconnect the motor from the unit and connect a lamp in its place, you should be able to turn the lamp on and off with the buttons. That will prove if the contacts are being held closed, the lamp will not draw enough current to trip the over current protection.
I have had this happen and it was down to dust in the holding contacts, a quick blow out with my air line fixed it, compressors are very useful at times.
Regards,
Dave
My tool kit is almost complete, only a few more to get.
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Re: Motor question. Sigh.

Postby 9fingers » 02 Jun 2016, 20:36

Sorry I've come late to this one!

I agree with Dave in that the holding contacts (marked 13 and 14) are not doing their job.
Dust is often the problem. Or is could be a loose connection on the control side.
WITH THE POWER OFF, connect an ohm meter between 13 and 14. Pressing the start button, should make the meter read zero.
Pressing the contactor in manually with the black buttons between terminal 1 and 2 should have the same effect.
I suspect that the second test will fail and a blast of compressed air should rectify this.

HTH

Bob
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Re: Motor question. Sigh.

Postby PeterBassett » 03 Jun 2016, 10:25

Thank you all. I'm going to have a look at the starter now.
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Re: Motor question. Sigh.

Postby PeterBassett » 03 Jun 2016, 10:48

OK I've tested terminals 13&14. It normally reads 1 on the left, which I believe is infinity on my MM.

Pressing the start switch drops it to 1 ohm. Pressing the contactor tab only drops it to 525!

I'll have a go cleaning it out but I recently sold my compressor from.lack of use! :oops:

Thanks.

Pete
Last edited by PeterBassett on 03 Jun 2016, 12:50, edited 1 time in total.
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Re: Motor question. Sigh.

Postby Tusses » 03 Jun 2016, 10:53

you know how to whistle don't you ?
just put your lips together and blow :)
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Re: Motor question. Sigh.

Postby Tusses » 03 Jun 2016, 10:56

a bit of pipe or tube will help concentrate the blow :-)
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Re: Motor question. Sigh.

Postby PeterBassett » 03 Jun 2016, 10:57

Lol!

Out of curiosity, would this be a suitable replacement.

http://www.screwfix.com/p/hylec-direct-on-line-dol-motor-starter-5-5kw/8911g

If so I'll be less hesitant about attacking this thing with screw drivers.
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Re: Motor question. Sigh.

Postby 9fingers » 03 Jun 2016, 10:59

Contactors can be dismantled with care for more intimate cleaning. there can be a few ping-f*ckits involved so do it on the kitchen table or other completely clear area where the landing places of flying parts can be discovered.



Best replacement is possible the toolstation product with correct thermal overload selected. but lets not plan to resort to that unless desperation kicks in. If you want, post me the starter and I'll fix it?

Bob
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Re: Motor question. Sigh.

Postby PeterBassett » 03 Jun 2016, 11:55

Thanks for the offer Bob, that's very kind. I have however fixed it!

It took me a while to figure out that the actual contacts were at the top, just behind where the cables are screwed down, not buried down in the body somewhere.

Initially I blew through them but it made no difference. I then undid and pulled the cables out of the way and used a small fine file to clean the contact surfaces and then blew through.

That made the difference and now it is again reading 1 ohm on all contacts. I put it all back together to test the motor and it starts and runs lovely.

So to summarise, if the motor starts but stops when you take your finger off the button you should probably suspect the starter. Fixing it is easy if you first (ask on the internet) spend some time to find the contacts and then give them a clean.

Thank you everyone, you've been of great help.

Pete
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Re: Motor question. Sigh.

Postby Tusses » 03 Jun 2016, 12:05

result :mrgreen:
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Re: Motor question. Sigh.

Postby PeterBassett » 03 Jun 2016, 12:13

Maybe, the starter is making a buzzing sound. Maybe its on the way out. I've ran it without the cover and turned the lights off. I can't see any sparking. It varies if you move it around.

Still working at the moment. I'm going to stand here and use it for a while and see how she does. No unattended running for this I think.
Last edited by PeterBassett on 03 Jun 2016, 12:49, edited 1 time in total.
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Re: Motor question. Sigh.

Postby 9fingers » 03 Jun 2016, 12:34

The buzzing sound is not unusual and quite often starts after a contactor has been disturbed and sometimes settles down after while.
Now you have it working again seal up all dust ingress holes with tape for hopefully a trouble free rest of life.
Now you understand a bit more about them, diving into others should not be so daunting. :lol:

Cheers

Bob
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Re: Motor question. Sigh.

Postby PeterBassett » 03 Jun 2016, 12:48

Thanks again. I'll do a small wip post about the build later, everyone likes photos. ;)
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