Wiring up my compressor. Help please...

[tomfc]

Well in the workshop next to me there there was a larger 200+ liter compressor in there, but this was never seen running by me running.

Its a single phase motor on it.

So i spoke to the landlord and he id me a good deal on it, so i had a little play with it today and tried to wire it up on a 13A plug but it just kept blowing fueses and not let any power get through to the motor.

So i bypassed the 13A fuse (silly i know) and this managed to get the motor to spin up for about 5 seconds before tripping the power out.

Also there was two wires that came of a switch and these when to a switch that was on the wall when it was in the unit next door, but whatever i do with these wires the motor kicks in...

Any help on getting it wired up would be great, im guessing its not supposed tobe run through a standard 240v 13A plug. So please could someone point me in the right direction on what bits i need.

 

[Jaeger_S2k]

A picture would be good and details of what the plate says on it.

Make and model number, Oh and you're almost right, silly - no, stupid yes!

Now STOP plugging it into the 13amp socket!

 

[tomfc]

Yes i know very stupid, but i just wanted to make sure it would run as its not been seen running and if i couldnt get life into it i wouldnt have brought it.

Heres a picture of the compressor:

This is the plaque on the electric motor, i think it reads:

Mapak Stayrite, single phase motor.
KW 2.2 PH1
rev/mini 1420 HZ 50
V 230-250 / 460/500
A 17.5 / 8.75 Cap 160 / 200

This is the wiring block on the motor, has marks 1, 2, 3, 4, 5 for each terminal starting at the top right going anti-clockwise.

When i got it, it was wired for:

1 - live
2 - nothing
3 - nutral
4 - goes to some sort of coil
5 - goes to goes to other wire on coil

This is the switch that sits between the motor and twin pumps, the two wires are just hanging and not connected to anything, and whatever i do the motor runs straight away...

This is the plaque on the pumps:

And this is a random plaque, thinks its just a servicing plaque:

Any help would be great.

 

[rtbcomp]

That switch should go between the motor and the mains. It looks like a 3-phase switch, just use two of the pairs to switch live & neutral.

The chances are it's broken if it's been disconnected.

Try running the motor with the belt off, if it stills blows fuses get it checked out by an electrician. From the plate it looks like it takes 17.5 Amps starting, 8.75 running, so the surge will blow a 13A fuse. What size trip does it trip?

 

[eil]

It is single phase take off the coil as you call it and get that checked thats your capacitor it should read 160 to 200uf. thats a 3hp so cant connect it with a three pin plug.

 

[tomfc]

Thanks for getting back to me.

Yes thats what i thought about the switch, however when it was in the unit next to me the wires went directly to a switch that was on the wall, and no other wires going to the switch... but this didnt make sense to me.


So you think that that with the belt off it shold stop tripping fueses?

Is the thing i refered to as a coil a capacitor then? if so there might be a fault with that as the plastic cover is easily removed as the end cover is broken off, then it looks like a roll of paper or similar inside, but it does look all intact.

Iv had a bit of a hunt round on the internet and it looks like it needs to run off a 30A breaker and hard wired to the power supply?

Ill have a look at the size trip its running later on.

Thanks again for all the help.

 

[R Kraft]

If it takes 17a to run it at 230v, it may take 3 or 4 times that much to start if, you may need a slow blow fuse or whatever they use over there.
The thing that has the end broke off has rolls of foil separated by paper that is damp with an electrolyte, it may be dried out and dead.

 

[wyn]

I have a similar compressor and it takes a bit to get the pump up to speed. (3hp)

I have had it temporarily wired to a 30 amp supply. Tried 13 amps for starters and nowhere near enough.

 

[Gary900r]

Did the switch on the wall have a start button and a stop button?.

 

[eil]

If you can see the roll of paper in the capacitor then that is definitely shot, new one needed before you try running it again.

 

[graffian]

Is that a start capacitor?

I just so happen to have a pair of new start caps that I bought for a motor and never fitted.

 

[tomfc]

Thanks for the replies.

So am i looking at wiring it direct a 30A breaker? or will i need more/less than this? i had a check today and there are a few breakers installed in the box, one of them is 32A and this isnt being used, so could i use this?

Also with the thing i called a coil i take it this is a soft start capacitor? If so when i unplugged it it wouldnt kick the motor in and when i touched the wires together and tried to start it nothing again, so does this mean that capacitor is still good or is that not how it works?

When i took the paper bit out the plastic there is a wax coating and lumps of was all over it...

If i do need a new one how do i know what type as i had a quick search on ebay and there are loads of different types.

 

[R Kraft]

The plate says it takes a 160-200uf start capacitor, does the old capacitor have anything printed on it ?

 

[tomfc]

Thanks for that, didnt think to check the plaque.

So do you think it will need a new one? because as i say when i bypass the capacitor it doesnt run, but when i have it connected up it runs for a few seconds...

 

[graffian]

Can't tell from the plate whether it's a start cap or run cap, someone who knows more about motors can probably tell. I would guess it's a start cap, but could well be wrong, I can't see any sign of switches or how it's wired.

If it's a start cap it's connected only at start up and you only need a start cap.
If it's a run cap it's connected in all the time and you need a run cap.

Just read what you wrote in your last post. more confused. I would check the motor with a meter, pull the belts off and try the motor without the load.
also try turning the pump by hand, they do get real hard to turn when not used for a while.

 

[tomfc]

Not sure tbh, the capacitor is run directly off the motor with no switched between it...

There is some writing on the casing of the capacitor but its all rubbed off so i can make any of it out.

I did take the fan cover off the motor and it all turns over prety easy, so i dont think its to do with something restricting it to turn over...

 

[R Kraft]

All of the run capacitors that I have seen were full of oil.

 

[eddie49]

I'm fairly sure it will be a motor start capacitor. You need to look for 160 to 200 uF, 350 VAC or more. Three or four of these in parallel will do the job:
http://cgi.ebay.co.uk/Motor-run-cap...66:2|39:1|72:1683|240:1318|301:0|293:1|294:50
To check if it is worth proceeding, you can spin the motor up by hand, without load. Take the belts off, discard the old capacitor and insulate the leads to it, wire the motor to the 32A breaker. Switch on - the motor should hum. Spin it by hand, in either direction. It should run up to speed. Switch off; as it slows down you may hear a click inside the motor. That would be the centrifugal switch on the rotor for the capacitor, confirming that it is a capacitor-start motor.

 

[eil]

Tomfc as my previous post that capacitor is shot mate, you need a 160/200mfd electrolytic start capacitor. The motor is capacitor start induction run thus no run capacitor. The start capacitor is connected to the centrifugal switch or other starting device but you cant see it because its inside.
The question now is why has the capacitor failed, which could be.
Too many start-ups in an hour.
Trying to start against pressure causing the start cap to be in circuit too long.
The starting device eg centrifugal switch welded together keeping the cap in circuit thus tripping the mcb/blowing the fuse.
New capacitor required first then we can move on to "tomorrows exciting episode"

 

[tomfc]

Hahaha ill hunt down a 160/200mfd electrolytic start capacitor. or can i use 3 of the ones posted in the ebay link?

The casing of this capacitor a is cracked down one side and part of the top cracked completely off, so i think the damage is more down to it being hit or similar...

ill have a word with my electrician mate and ask him to wire it up the 32A breaker for me and see if he knows anywhere local i can get a start capacitor.

When i was truing to get it all up and running i did try it with the capacitor not plugged in and it motor did hummmm really load and dimmed all the lights, so i decided not to do that anymore lol.