Compressor 3hp motor DOL starter question

[pc1966]

It is not uncommon for the sort of capacitor used for motor starting to be 20% or 25% tolerance, so it might still be in-spec, however, if you have any reason to doubt it then replacement might be cheaper as @DPG suggested.

Out-of-spec capacitance won't trip your RCD though, that would require leakage to earth in some way. Insulation fault is most obvious, but sparking and a bit of filter capacitance, etc, can cause intermittent issues. Ideally get someone with an insulation tester to check for L+N to E leakage at 250V or 500V DC.

 

[styleruk]

It is not uncommon for the sort of capacitor used for motor starting to be 20% or 25% tolerance, so it might still be in-spec, however, if you have any reason to doubt it then replacement might be cheaper as @DPG suggested.

Out-of-spec capacitance won't trip your RCD though, that would require leakage to earth in some way. Insulation fault is most obvious, but sparking and a bit of filter capacitance, etc, can cause intermittent issues. Ideally get someone with an insulation tester to check for L+N to E leakage at 250V or 500V DC.

That's a good idea, I think this weekend I'm going to wire direct from the motor to a plug and test if it starts, just to check that the DOL or socket is not causing an issue, at least I'll see if the motor spins up, then I know it's not the caps or motor and can re-look at my wiring at the wall. For all I know the Clarkes DOL has copped out.
One small thing I noticed, first it tripped the RCD at the house and everything went off (reason why I'll only test at the weekend and not in the evening, wife is getting irritated). But after I tinkered and rewired all the socket connections, it then triped the garage isolator (at the house board), and not the RCD, that tells me something different that I only partly understand. Which is why I'm thinking of bypassing the DOL and wall socket for now just to test.

 

[styleruk]

Another question I have, where is a good place to buy a replacement starter Capacitor. The internet is awash with wrong products.

 

[styleruk]

Before I plug direct to the motor, I checked continuity across live/N from the motor and it shows 0 resistance, is that right? More worryingly, earth to L/N was ~500.

 

[marconi]

Before I plug direct to the motor, I checked continuity across live/N from the motor and it shows 0 resistance, is that right? More worryingly, earth to L/N was ~500.

Would you like me to visit? You live about 15 minutes away from me. Private Message(PM) me.

 

[styleruk]

OK, I phoned a freind and did a bit more research, the resistance between the N/L is OK but there should be no continuity between L/E. This suggests that the motor is leaking to earth and that could be moisture as some have said.
They also suggested I disconnect the earth and test that. I may do that tomorrow just to test.
Then it's back to 'marconi' suggestion of drying the motor out correctly.
That's my plan anyway.

 

[pc1966]

They also suggested I disconnect the earth and test that. I may do that tomorrow just to test.

No, no, no!

That is an incredibly dangerous thing to do, more so when the expectation here is it will become live!

Then it's back to 'marconi' suggestion of drying the motor out correctly.

Is there any sign of water?

You might have metallic swarf in there, or something else like a damaged cable (e.g. missing/damaged grommet so cut through).

If you can isolate the motor and test it using a suitable IR tester then you will know if it is in need of repair/replacement or not.

 

[davesparks]

That's a good idea, I think this weekend I'm going to wire direct from the motor to a plug and test if it starts, just to check that the DOL or socket is not causing an issue, at least I'll see if the motor spins up,

I'd say this is a very bad idea, removing the overload protection and energising the motor to see what happens is not a sensible plan.

If you suspect that the DOL starter is at fault then test it, don't just bypass it and see what happens.
A simple test for voltage at the outgoing terminals will tell you whether it is working or not, this could even be achieved by connecting a simple lampholder to the outgoing terminals.

 

[davesparks]

They also suggested I disconnect the earth and test that. I may do that tomorrow just to test

What exactly do you mean by this?

Your best bet right now is to take @marconi up on their generous offer of help

 

[styleruk]

Well well well. I took the motor clean off the compressor today, that took a bit of a configuration of the garage, but it was the only way I could find out for sure. Took all the wires off and turned it upsidedown and bloody hell! A cup of rusty water poured out FFS. I feel a little stupid now, but it does go to show that questioning things first helps.

So I striped all I could off and it's now resting in the oven plate warmer, I'll keep an eye on the temp and keep that down to 70c max. I'll try and use the plate warmer to dry it out for a couple of days, maybe not overnight as I'm not too sure yet how hot it will get. But that should dry out most of the moisture left in there.

I just hope it has not trashed the motor.
Whilst on holiday, I heard the south got some very bad weather in November, but it must have been pretty horrific to get wet where the compressor was, needless to say I will fix that before putting it back.

PS; no continuity between L/E when empty of water.

 

[styleruk]

What exactly do you mean by this?

Your best bet right now is to take @marconi up on their generous offer of help

I was told that many a time, this person has found an appliance tripping, so they take off the earth and run it for a while to dry the moisture out. I was dubious as they were not an electrical expert by any means. Hence the reason why I asked around first. Hopefully drying out the motor fully will be enough to save it exactly as marconi said.

 

[davesparks]

I was told that many a time, this person has found an appliance tripping, so they take off the earth and run it for a while to dry the moisture out.

Do not do this, you will be putting yourself at significant risk of electric shock which could kill you or someone else.

The earth connection is there to ensure your safety in the event of a fault. You know that there is a fault in the appliance because the earth and the protective devices are doing their job and preventing you from being injured.

If you remove the earth connection and energise the machine then you are removing the thing that is keeping you safe from harm.

This is the sort of thing that you would see someone do on TV and think to yourself "I can't believe anyone would be that stupid"

 

[styleruk]

Well drying it out in the oven plate warmer did the trick. Powered up nicely with no load, now to spend the day renovating it seeing as I've pulled tge garage apart, honestly be easier to buy a cheap clarke comoressor and chuck it every 10 years.

 

[styleruk]

An update on my compressor; I think my motor is trashed now, started up the weekend and it made a racket and started smoking. I think the water ingress took it's toll on my cheap machine mart motor. But then, no motor should have that much water in it. Should have fixed the roof first eh!
So I'm picking up a replacement motor..
Meanwhile, it did a good job spraying my old Singer and now a Land rover.

 

[styleruk]

Picture of my latest rebuild, complete with thatcham approved security dogs. Again, not the best paint job but suits the vehicle perfectly, easier to paint as I didn't want it as shiny. This is a classic next year 1985. So the compressor motor has done a good job so far.
I'll be painting the inside of my house next using the compressor. Have 60m line and separate small receiver. So asking dumb questions on another forum about that now.
Meanwhile, I must visit machinemart and empty my wallet. first name terms there. Maybe when I swap out the motor, I'll strip it and find out why it smokes, could be something simple, but I've convinced myself the water damage trashed it.

 

[DPG]

Picture of my latest rebuild, complete with thatcham approved security dogs. Again, not the best paint job but suits the vehicle perfectly, easier to paint as I didn't want it as shiny. This is a classic next year 1985. So the compressor motor has done a good job so far.
I'll be painting the inside of my house next using the compressor. Have 60m line and separate small receiver. So asking dumb questions on another forum about that now.
Meanwhile, I must visit machinemart and empty my wallet. first name terms there. Maybe when I swap out the motor, I'll strip it and find out why it smokes, could be something simple, but I've convinced myself the water damage trashed it.

View attachment 113824

Looks very nice that.