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Ed_Dinning · 31-12-2014, 11:45 AM

Hi Gents, a friend has a SIP Industrial Products belt/ disc sander with a 500W motor.
The motor is a 5 lead cap start and run type (12uf and 100uF) controlled by an
RNS-Tech 4 wire module.
It appears to be operating on 1 winding only, possibly the start winding as it is getting hot quickly.

Anyone any experience of these before I do full strip down?

Thanks, Ed

Refugee · 31-12-2014, 12:21 PM

I would check both capacitors before stripping it down. The start capacitor will not switch out without the extra speed from the run capacitor being there.
It is worth a try before the strip down.

Ed_Dinning · 31-12-2014, 07:42 PM

Hi Gents, on examination it was a bog standard induction motor with a 12uF run cap.
This had an extra 100uF added across it for starting.
A simple spring loaded switch now performs this function.
Its quite a new machine so the smoke/ smell was probably varnish solvent. It will get a longer run later but the motor seems to have survived.

I'd still like to know what was in the module though.

Ed

Refugee · 31-12-2014, 07:51 PM

Most likely a timer that cuts the start capacitor in for a second or two at switch on.

AlanBeckett · (This post was last modified: 31-12-2014, 08:28 PM by AlanBeckett.)

As far as I can tell most modernish Motors have an Electronic Start Switch as opposed to the old Centrifugal ones. I had one that needed a new Switch. It was pretty straightforward - see attached.

Alan

rele_klixon_2cra.pdf (Size: 478.87 KB / Downloads: 41)

Ed_Dinning · 01-01-2015, 01:50 PM

Hi Gents, this is a nice potted Chinese unit, appears to be all solid state, so not sure what is in there.
Problem resolved with the unit as I'm now using a spring loaded start switch.

Ed

Refugee · 06-01-2015, 11:02 PM

I have found a motor starter that can be opened and all the components can be seen.
I will do a separate thread if you want to see the insides.

AlanBeckett · 06-01-2015, 11:50 PM

Is that really a Motor Starter or just a Delay Switch?
What are the contact Ratings?
The one I pictured above works on the Back EMF of the Windings as the Motor runs up I believe.

Alan

Refugee · 07-01-2015, 01:17 AM

When I salvaged it there was also a big contacter driven by it. It would have been part of a large motor starter.
The delay setting can be turned to zero.
The label is marked 5A but the relay inside shows 10A. They must have built it to last.

**Nick** · 07-01-2015, 05:42 AM

The 5A/10A derating may well be because its driving reactive loads.

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