Compressor 3hp motor DOL starter question

[styleruk]

the starter is a big switch designed to take the motor current what operates this big switch is a little switch, in your case the pressure switch.

If you're not clear on how to connect them up correctly why not ask your brothers mate to have a look. Or just buy a prebuilt unit big enough for what you need. Try Atlas Copco they make good compressors with everything built in.

I have asked exactly that to be sure I get the best I can. Sure, I can spend over £1k for a built unit that has a receiver this size but I would rather renovate my 1960 classic compressor tank to suit everything else in my garage for £300.
I'm not using it for professional usage, it's for now and then and I suppose I could buy a cheap smaller compressor for less and save my time learning, but when this one is finished (and I'm in no hurry), it'll see me out. Plus, I enjoy the small challenge.
I'm rebuilding a classic car in between, so it's a nice distraction during this lock down period.
But thanks to all for the advice so far, I'm slowing going up the right path. I'll post a picture when it's done.

 

[DPG]

I have asked exactly that to be sure I get the best I can. Sure, I can spend over £1k for a built unit that has a receiver this size but I would rather renovate my 1960 classic compressor tank to suit everything else in my garage for £300.
I'm not using it for professional usage, it's for now and then and I suppose I could buy a cheap smaller compressor for less and save my time learning, but when this one is finished (and I'm in no hurry), it'll see me out. Plus, I enjoy the small challenge.
I'm rebuilding a classic car in between, so it's a nice distraction during this lock down period.
But thanks to all for the advice so far, I'm slowing going up the right path. I'll post a picture when it's done.

What car are you working on?

 

[styleruk]

What car are you working on?

Singer Gazelle. Nothing exotic, but a good work horse practical classic. Finished a ton of welding with her, she is now in patchy grey primer here and there, but the crap all-in-one compressor that was bolted to my receiver was just not up to the job of spraying. So I'm upgrading that, it will look more original with a twin cylinder on top. Just renovated an old 2 post lift that I got for a favour, it was rusty as hell but now smells of grease and hammerite. I recently learned a lot about hydrolic lifts and can now lift the old girl up to work on her. It's the same with that, I could have spent a couple of grand on a lift, but would rather spend the evenings figuring it out myself and trying to fix something that is fundamentally better quality.

 

[DPG]

Sounds interesting. Post some pictures if you get chance.

 

[ChipFanDave]

My mistake miss read the original post and got mixed up thinking you were using a 32A motor. I don't think you will need that DOL starter and overload relay if the pressure switch is a decent one that's rated for 16A you could just use a 2 pole motor protection circuit breaker. These are suitable for motor disconnection as well as overload protection.

 

[styleruk]

My mistake miss read the original post and got mixed up thinking you were using a 32A motor. I don't think you will need that DOL starter and overload relay if the pressure switch is a decent one that's rated for 16A you could just use a 2 pole motor protection circuit breaker. These are suitable for motor disconnection as well as overload protection.

I was advised to use the starter as it will pull a lot when it kicks in. Question is, where do I put it in the supply, before pump or on wall going into the pressure switch.

 

[ChipFanDave]

Not sure what consumer unit you have or if you have spares ways in it but some of them will fit in there if not buy a small housing for switched O/L. I'll PM you some links for the bits when I've finished feeding the family !

 

[davesparks]

I was advised to use the starter as it will pull a lot when it kicks in. Question is, where do I put it in the supply, before pump or on wall going into the pressure switch.

The starter will have no bearing at all on how much the inrush is

 

[styleruk]

fired it up today whilst I await the DOL, works very well. Would like to post a picture but apparently jpg is not recognised so I can't be bothered to figure that out.
The lights flick slightly when it fires up, but I have not run her for a long time yet until I fit the starter.

 

[styleruk]

So, eventually the starter turned up. Meanwhile, been getting mixed messages form various people, most staying, you don't need a starter for that!
But I've got it and fitted now so tough, I have one.
I can't tell the difference with it fitted, maybe it seem to start slightly less aggressively, which, if true, is a good thing.
I'd like to share a picture of it but apparently a 'jpg' is not an image as expected!
But overall, i've repainted the compressor, added a dump valve so the cylinder heads do not have pressure when the motor starts, a one way valve, rebuilt the pressure switch and 3d printed a new cover for it, turned up a new button to switch it on and off, obviously fitted a new pump and motor, all new connector hoses and high temperature hose for the pump to receiver and starter with overload protection set to 10 amp currently. (that's adjustable)...oh and a crap oven isolator which I'm going to send back. I can't believe such a low quality switch could be sold.

Only one frustration in all this. (short rant coming up, I apologise)
1) Strip, sand clean receiver and asy; 2hrs
2) paint, 30mins
3) fit pump and motor, drill new holes, align pullies etc; 1hr
4) fit new regulators and air gadgets to compressor; 20mins
5) fit electrical boxes to wall; 10 mins
6) Align flat head screwdriver to godforsaken retarded, out-of-date, frustratingly irritating, dumb---- flat head screws that all electrical fittings seem to have; 600000000days

Why, for crying out loud, why flat heads? come on, there must be a logical reason to use these? I mean , Philips are so much quicker and easier and secure! It just beggars belief. I curse when I come across the odd one in my 1965 classic car, but all electrical fittings have this crappy screw head that I forever have to fiddle around trying align my screwdriver to, then slip off and swear as I faf around looking for it again. Wiring up took 100x longer than it should have, it's not hard, just stupid. I designed a cover and sent it to my 3d printer quicker than I could do up all the frikin stupid screws on the electrical fittings. Even the ones that hold the front cover on are stupid flat heads.

Rant over, again, I apologise.
Thanks for all your help here.

 

[DPG]

If you pick the correct size screwdriver for the screw then it shouldn't slip off the head.

 

[styleruk]

If you pick the correct size screwdriver for the screw then it shouldn't slip off the head.

I know, just a pet hate. Same with Philips, torx and any other head type, but flat is simply anoying.

 

[telectrix]

I know, just a pet hate. Same with Philips, torx and any other head type, but flat is simply anoying.

forum is having problems with uploading pics. what you can do is either upload as a pdf, or send pic. to image host site, then post a link to it.

 

[pc1966]

So, eventually the starter turned up. Meanwhile, been getting mixed messages form various people, most staying, you don't need a starter for that!
But I've got it and fitted now so tough, I have one.

As already explained, a motor starter has a specific job to deal with: to allow motor start surges while also protecting against motor overload, where as the supply MCB or HRC fuse is there to protect the starter from massive fault currents.

You won't notice a good starter doing its job, but without one if the motor is locked or otherwise overloaded you will find a burned out motor which costs a bit more to replace than the starter costs!

 

[Lucien Nunes]

Align flat head screwdriver to godforsaken retarded, out-of-date, frustratingly irritating, dumb---- flat head screws

Whatever you choose to do in life, never even contemplate becoming an organ-builder.