Compressor problem

[bravheart]

Ok long story and a catalogue of errors ended up with the compressor being plugged into a 13amp plug extension

boom

Just had a quick look today expecting a burnt out motor but getting a continuity reading on all the wires between the plug and the on/off pressure switch ie. plug live to switch live and neutral, plug neutral to switch live and neutral.
Does this mean the power cable might be melted and bare wires touching or is that an over simplification?

 

[Lincs Lass]

What size is the motor

 

[bravheart]

3hp belt drive with 150l tank

 

[Lincs Lass]

Bet its melted the extension cable ,,ive the same size but its wired into a 16a blue plug ,that was the advice from the company I bought it from .

 

[Goweresque]

I'm at a loss, why is plugging a 240 volt machine into a 240 volt supply going to make some thing go bang in the machine itself? If the current it drew was too big for the extension cable then thats the most likely thing to go bang, surely? Have you tried plugging the machine into whatever supply it should have, is it working then or not?

 

[bravheart]

Bet its melted the extension cable ,,ive the same size but its wired into a 16a blue plug ,that was the advice from the company I bought it from .

16a plug was changed to 13a and plugged into extension in an emergency. Given the readings on the multimeter was wondering if that was exactly what had happened but on the power cable.

 

[Lincs Lass]

Better parking the compressor as close to the socket as possible and running 3/4 inch pipe work

 

[bravheart]

I'm at a loss, why is plugging a 240 volt machine into a 240 volt supply going to make some thing go bang in the machine itself? If the current it drew was too big for the extension cable then thats the most likely thing to go bang, surely? Have you tried plugging the machine into whatever supply it should have, is it working then or not?

Told you it was a long story! Basically after some storm damage we lost the power supply in the shed with 16amp plug, forklift with a flat tyre and some hungry cows meant that operator thought changing the plug seemed the easiest and quickest option at the time not knowing compressor was in that shed for a reason. Believe Extension blew a couple of fuses before the motor stopped.

edit. Just checking it all out, got one of those 24l jobs to keep things going in the mean time but plugging it back in to the origional supply atm. to try is a non starter.

 

[C.J]

Surely the most likely thing to go are the 13 amp fuses in the 13 amp plugs.

 

[bravheart]

Surely the most likely thing to go are the 13 amp fuses in the 13 amp plugs.

A cattleman will keep replacing with something till it works

 

[KennyO]

Is the capacitor ok.

Educate the cattleman that he could have take compressor with a tank full of air. Should get enough air out of tank and into tyre to make it mobile.

 

[Tomr10]

Has it tripped a ring

 

[Goweresque]

Told you it was a long story! Basically after some storm damage we lost the power supply in the shed with 16amp plug, forklift with a flat tyre and some hungry cows meant that operator thought changing the plug seemed the easiest and quickest option at the time not knowing compressor was in that shed for a reason. Believe Extension blew a couple of fuses before the motor stopped.

edit. Just checking it all out, got one of those 24l jobs to keep things going in the mean time but plugging it back in to the origional supply atm. to try is a non starter.

My point is that changing a 16A plug to a 13A plug is not ever going to overload the wiring in the machine itself, by definition all the power cabling and internal wiring etc are designed to cope with 16A supply. All that can happen is the machine attempts to draw 16 amps, which will blow the 13A fuse in the plug, or the 13A fuses in the extension cable, or all of them at the same time. I can't see that the compressor could have been harmed at all.

 

[defender]

As Kenny says try the capacitor , or take the lid of the plug and check not shorting in there

 

[bravheart]

Thanks for all the replies guys we have all learnt something but nothing else has been tested, after the damage the electricity supply was disconnected in that shed by an electrician so no more testing or trials can be done.
My question was more of an -
I don't understand electrics thread.

Would get a length of 16a cable if someone could confirm a melted cable needing changed from my continuity readings on both sides, or could this reading indicate a more costly motor repair.

 

[Goweresque]

I'm getting a continuity reading on all the wires between the plug and the on/off pressure switch ie. plug live to switch live and neutral, plug neutral to switch live and neutral.

That could be because the circuit is being made inside the motor. Live and neutral are effective joined inside the motor, the whole thing is one big circuit. To test the continuity of the power cable, you'll have to disconnect it from the switch on the machine and test it in isolation.

TBH until you can actually plug the machine into a supply capable of supplying 16A safely and check whether its actually working or not, I'd hold fire on doing anything else.

 

[David.]

You can ruin the motor windings by running off a long insufficiently large capacity extension lead, due to voltage drop. Ought to be at least 4mm2 cable cores.
Motor is running at probably only 200v and drawing increased amps to compensate.

 

[bravheart]

Thanks again, was hoping it might be a quick fix but this the reply I was looking for

That could be because the circuit is being made inside the motor. Live and neutral are effective joined inside the motor, the whole thing is one big circuit. To test the continuity of the power cable, you'll have to disconnect it from the switch on the machine and test it in isolation.

TBH until you can actually plug the machine into a supply capable of supplying 16A safely and check whether its actually working or not, I'd hold fire on doing anything else.

Will switching the pressure switch off isolate the motor windings or do the wires need disconnecting completely?
Moving on how could the capacitor be tested?

Repairs are currently in the hands of the insurers so could drag on for a while, might be pushing it a bit but was wondering whether a compressor repair could go on the list if it’s more than a cable replacement.

 

[bravheart]

Here's the problem, could take a while to sort out.

 

[KennyO]

@bravheart i think when the capacitor is the issue the motor normally hums but won't start.

Also if you take the cover off on the box on top of motor sometimes you see it burnt or damaged.

Have you not got a sparkie who will take a quick look for you?