Clarke Boxer blowing fuses and worse - any assistance welcome

[Gr8fun]

Hi everyone
I run a Clarke Boxer compressor with my homemade CNC plasma table.
It had started popping fuses and tripping the MCB.
The compressor is like this one
https://www.machinemart.co.uk/p/clarke-boxer-14200-200-litre-belt-driven-air/
and a few years old now.
After some trawling the internet it was suggested the startup current could be the problem so a 16amp blue plug has been fitted and a 20amp breaker connected at the fuse box.

Still no good. The motor would move a few degs for a fraction of a second then pop.

The compressor can easily rotated by hand with hardly any effort do I'm sure it is not the compressor side stopping things
I have removed the cover of the plastic casing above the motor where there are a couple of what look like large capacitors, there was some white smoke dissipating as the cover came off.
Since then, nothing at all and the mcb does not pop.

My question is, what would be the most likely reason for the capacitor to go?
Are they prone to going or would this be a symptom of something else?

Any suggestions or advice greatly received.

 

[rtbcomp]

Welcome to the forum.

Those cylinders are the start & run capacitors, have a look to see if there is any swelling or leaking.

 

[Parm]

Almost certainly motor start capacitors. I had the same issue with my ABAC Comp a few moths ago.

Very cheap to buy from the web once you know what size you need

 

[Gr8fun]

Thanks chaps. Excellent news.
The white one has a small amount of residue that seems to have leaked from the top of case.
I trust the info on the sides will allow me to get the correct replacements.
Would it be just one or do they go in pairs?

Your help has been most calming! It is really very much appreciated.

Just out of interest, what are the 25/70/21 numbers for?
I've found 50uf capacitors for about £9 delivered, do I need to consider any other values?

Gr8fun

 

[rtbcomp]

If they're not too expensive I'd replace them both. If you can't get the exact voltage rating, go higher.

 

[dobbslc]

Just measure them so you get the right physical size.
If you're lucky it's the caps blown if not it's the motor, I've got a 150L SIP with a very similar looking motor that was kaput when I got it, a new motor from machine Mart was about £130 so not a total disaster.

 

[Pilzy]

Hopefully the new capacitors will have you up and running again.

Been there with my ABAC 150 litre earlier in the year and went through pretty much everything on the damn thing to get it running!

Are you getting a good hiss when you hit max pressure and the compressor shuts down?

Another reason for burnt out capacitors/thermal switches is the head still holding pressure causing the start capacitor to struggle pumping the piston on it`s first few revolutions.

Best of luck with it. I know how soul destroying it is when your little bomb stops ticking!

 

[angellonewolf]

from memory the nf need to be the same but you can go higher on the voltage and generly its better if you do (bewere higher volts normaly mean bigger capactior so cheak you have the room for them to fit more inportant on tvs and such )

one other thing to cheak if they say the temp of them make sure it matches or is higher than the orignal

 

[Toleman]

Try this. Slightly different size but less than £4. Is that electrolytic or PP?

https://www.amazon.co.uk/Polypropylene-Film-Motor-Capacitor-CBB60/dp/B00BG6L9E8

 

[Toleman]

Also putting 16a plugs on removes the fuse. That is unless it has them internally.

 

[carbon]

Will not be an electolytic as its ac, think a lot of motor capacities are now metal used polypropylene. But it does look like there is an overload in the case, but it won't trip as quick as a fuse so could possibly do some damage to the motor

 

[brightspark]

ring mains are a dead loss and will still work when there are loose wires in the system that can cause an overload potentially running 7kw of a piece of 2.5mm cable then burn the cable end out at the fuse holder or another socket without tripping a 32 amp breaker . radial circuits are far safer and easier to fault find when the sh ..t hits the fan

 

[dobbslc]

I've just bought a new house and the wiring is really bad, I'm tempted to wire using radial circuits on 20 amp RCBO's.

 

[Gr8fun]

Cheers chaps. I tried the capacitors to no avail, so a replacement motor from MM it was. all good.
Just have to work out how to remove the pulley from the old motor.....

 

[rtbcomp]

Have a look for one or maybe 2 grub screws and slacked them right off. You should really use a puller to pull the pulley, warming the pulley should help by causing it to expand and reduce its grip on the shaft.

When fitting it to the new motor make sure the shaft and hole in the pulley are absolutely clean, put the key in the shaft and push the pulley on, again if the pulley is heated it will make this job easier. Tighten the grub screws.

Make sure the pulley on the motor lines up with the pump pulley.

 

[DrDeAtH]

I've just bought a new house and the wiring is really bad, I'm tempted to wire using radial circuits on 20 amp RCBO's.

I've done this on a few projects now. Makes working on the system much easier as you have to power less of the installation down.

 

[brightspark]

I've just bought a new house and the wiring is really bad, I'm tempted to wire using radial circuits on 20 amp RCBO's.

a lot better than ring mains. less hassle when there's a fault and u only trip one circuit ring mains were designed when there was a copper shortage as they use less cable but there a pain in the neck when faults develop and will still run with cable breaks in the circuit