snap-on compressor help

[mk1cortinaandy]

hey guys,

a little while ago i purchased a large single phase compressor and it worked where i picked it up from.

after travelling back to the unit on the back of my volvo 740 as soon as you attempt to strike it up it trips the electric, investigating i checked continuity between live and earth and then live and neutral where i found a short circuit, i have checked the cabling to the motor which is all good. the motor in question has 2 capacitors on the out side of the box on top of the motor in the box i disconnected each individual part and checked for a short which i could not trace, i put all the connections back on and the short is back. from there i have very confused myself and could do with a few pointers from the guru's of retro rides.

thanks in advance for any help ;D and i promise to do a thread on my unit as soon as I'm settled



this is the offender in question

[omega]

are you sure its not your power supply not on good enough cable?

[cobblers]

A motor winding will typically measure very close to a dead short when not operating anyway - I'm guessing it trips the 16A breaker on the spur for your sockets?

One capacitor will generally be used for reducing the surge when the motor first turns on and will probably be bypassed once the motor is running, and the other is the "run" capacitor, active all the time. They will have a voltage and uF rating on the side,

A compressor that large with even a slightly tired starting cap will occasionally trip a breaker. Most multimeters won't be able to check a capacitor like that, but new ones aren't mega expensive (£10-20) and they aren't a big deal to swap.

[mk1cortinaandy]

to be honest I'm not completely sure, would you expect a short between live and neutral on a single phase motor? I'm not completely sure how it all works. thanks for your help though, i shall try it on a bigger breaker

[peanutsc]

Hope this is to do the 340!

I can see a plug on the end of the cable and if that compressor is anything like mine it will draw more than 13 amps to get the motor running from rest. It will probably need connecting straight to a consumer unit with a stronger fuse.

[mk1cortinaandy]

and if i can make it work i will invest in new capacitors as a service (sorry cobblers your post appeared when i posted) thanks guys

[mk1cortinaandy]

cheers guys i just made a trip over there and wired it straight out of a circuit breaker and she struck into life! so pleased!

[dodgerover]

16amp blue plug is probably the way to go, what was the size of the breaker it was tripping though?

[indyz12]

I bought a clarke 150L single phase. The PO had wired it to a socket and run a welding tip as the fuse.
It worked, but i knew it needed to be wired into a breaker. When i got it home and took the plug off - the wires were black. I had to cut 2 feet off the cable to get good clean copper wires.

[pork]

I sell air compressors for a living, bin the motor, not worth the hassle, you can pick them up for £140 plus vat from machine mart.

Or I can do you a new abac a29b for £525 inc vat and free delivery, which is the largest compressor you can run of a 13amp plug, next size up you'll need to hardware into a 16amp breaker

Www.air-technique.co.uk

[Darkspeed]

You will probably find that the breaker is not motor rated - why would it be - you may need to change the breaker for a C its probably a B type fitted.
Have a search for breaker types B C D and Z