3 phase switch?

[T i m]

Hi All,

My mate runs his own garage and has a compressor in a side building. To turn the compressor on / off he has to go next door, unlock, relock etc.

I suggested 'we' could simply fir a suitable (3 phase) switch into the armoured where the cable goes through the wall but wondered how expensive such would be?

All the best ..

T i m

[Grunff]

[Lurch]

Eh? You'd be better off trying one of these, just check the size of the MCB or fuse on the circuit and get the same rating, or next one up.

SJW A.C.S. Ltd.

[nightjar]

You are supposed to carry out a maintenance check (at least looking at the oil level) every time before you switch on a compressor. After switching off, the reservoir should be drained, to minimise internal corrosion. As he should be going out there to do those things, he may as well go out to turn the thing on and off.

Colin Bignell

[Grunff]

I was thinking of using the contactor remotely, which is why I suggested it.

[Lurch]

Perhaps some explanation then, maybe about what you intended, how to wire it up, suitable enclosure, cable requirements for the remote circuit. ..

SJW A.C.S. Ltd.

[Grunff]

One would hope that anyone considering modifying 3 phase wiring wouldn't need instructions on using a simple 4 pole relay!

[Lurch]

Doubtful, if the OP knew all that he wouldn't be asking such a simple question about the price of a switch. I know how to do it, but I still didn't have a clue whether you meant as a remote start\stop contactor or simply an incorrect pasting of URL's. ..

SJW A.C.S. Ltd.

[T i m]

[T] Boys boys boys .. !

So ... I 'understand' all about relays, timers, fuses etc through spending most of my life (yoof and adult) playing with the things (mostly as an Electronics Engineer but also though loads or weird stuff including wiring up a French tower crane ..).

What I don't have is a copy of the 'big book' or any recent practical experience doing such and it's nice to get the up-to-date info from those at the cutting edge ?

So, I may of been misleading when I mentioned the compressor was on the other side of the wall. This was where my mate moved it to some

10 years ago and I re-wired the 3 phase armoured supply to for him.

So, what he has at the moment is one of those big grey boxes with the Frankenstien switch (switch blades inside the box though ) on the side. I don't suppose the (re-wirable) fuses are the correct rating for the current load (excuse the pun) as this place has 'evolved' over the 30+- years he has been there.

So, I think the

looks (to me) like the modern equavalent of the big grey switch and mentions knockouts and some different sizes that I can choose when I know what load the compressor puts on the system (info plate).

I just wanted some idea of the cost of the switch (around +AKM-20 I now see) and any thoughts that would go along with the job. I would probably supply the switch / glands and labour free as he has helped me on many occasions (mainly letting me work on my ageing vehicles on his 4 poster in his heated workshop ).

Colin has raised another point though. That of the 'regular inspection' that should be done daily as you turn the compressor on / off?

I fit the switch on the cozy side of the wall and the compressor is "out of sight, out of mind ... " ;-(

Hmmmmm ...?

All the best ..(to all) ..

T i m

[T i m]

[T] Hi Steve,

Thanks for that. He used to switch it off on the cozy side of the wall by using the big Frankenstien switch .. till it started getting a bit tired. He now (for the last 10 years that I know of) uses the mini Frankenstien switch wired just in front of the compressor?

I don't 'think' it's a special (3 phase) switch but I also don't know how the compressor is equipped (relays etc?)

All the best ..

T i m

[Lurch]

What you could is put another switch, of the same type, in series with the normal power switch. That would get around that. ..

SJW A.C.S. Ltd.

[T i m]

That's sorta what I had in mind .. so it would go .

Big Frankenstien fusebox / switch

5m of armoured *New switch* armoured through wall to old switch Compressor (and possibly it's own starter gear) ?

All the best ..

T i m

[Steve]

Be careful, many compressors don't like being started like that. There is a special pressure switch which unloads the compressor as it starts, so it isn't trying to start straight into the load. Switching by just plonking the power on is a racing certianty to make the motor stall and blow fuses.

Steve

[Lurch]

I was thinking the actual power switch on the unit itself, or does your mate not bother with that and flick it off at the wall instead. Either way, point out the pro's and con's to him, then your covered if it doesn't do the machine any good! ..

SJW A.C.S. Ltd.