air compressor wiring help required

[rdautobody]

ok so to cut a long story short I had to buy another air compressor as my one was giving up and being used in a bodyshop it was essential that i replaced it.

anyhow my old compressor was single phase so was simple plug in and air was made

the new one i have here is unfortunatly not as simple.

its a 3 phase supply and the 3 lives and earth going in are all colour coded and fit perfectly, however there is one issue here,

there is 4 wires that are loose in the switch box that mount on the wall,

I have traced the wires and one of them is the live (brown wire) from the on/off swtich on the compressor it self

the second wire is the live ( brown wire) from the release valve on the end of the compressor.

the third wire that is loose is a blue wire with red tape on ( i would assume is a live???) this comes from the bottom of the reset switch

the last wire that doesnt have a home is the blue wire neutral from the release valve.

I am completely baffled as i cant see for love no money where they go or where they came from,

the two brown wires from the on off switch and the release valve were loose and just pushed into the switch box, the blue neutral wire from the release valve along with the blue wire from the bottom of the reset switch were poking out of the top.

Any help will be greatly appreciated as the bodyshop has come to an absoloute standstill!

ive had two electricians come out and said it was easy but neither returned

 

[rdautobody]

above is a picture of the switch box

 

[Marvo]

ive had two electricians come out and said it was easy but neither returned

:rofl::rofl:

Even with my new glasses I'm not 100% certain what you have there. It looks like a star-delta starter with a breaking unit maybe.

I'd stop what you're doing before you damage something. If you connect this up wrong then at best there will be one almighty bang followed by darkness. At worst it will cost you a compressor. You need to find someone who's familiar with motor controls to help you. The more lightweight domestic guys are going to struggle with this, I'd suggest a commercial or industrial type sparkie.

You're obviously not an electrician and I was going to relocate your thread to the DIY section but I'll leave it here for now because the guys most likely to have good info for you won't see it in there.

 

[Lucien Nunes]

Agreed, it's a star-delta starter, from left to right I see the start, run and line contactors and the timer, with the overload relay below the line con. I would expect the unloading valve to be connected across two outgoing lines and presumably the loose ends associated with the pressure switch (I think that's what you mean) had been taken via an external control switch.

As per Marvo, find a spark who routinely works with machinery - it will be a simple job for him to rectify this but a mistake can result in a motor burnout. I have seen so-called electricians wire up starters in the most bizarre ways, including one that correctly started the motor but then set it on fire. Because of these hazards, I am refraining from offering suggestions as to which terminals the loose ends should connect to.

 

[Darkwood]

Can you post a pic of your compressor connections i.e. the motor connections in particular im curious as to how the motor has been wired and whether it is set up for DOL or Star/Delta..

It dosn't help when the colour coding of the wires is misleading ... it would be better to replace with correct coded wires or remark but as i can see one flex isn't long enough to reach you starter controls i suggest you replace them.

You will have a pressure switch on the compressor that will act as a auto start/stop with lag and will be intergrated into the existing controls an alteration of the star/delta control will be needed..
-is the overload correct for the new compressor and looking at the set-up should be set to 0.58 x motor flc rating.
-what size is the compressor motor in Kw
-can we have a photo of the compressor too.

Is their any controls on the compressor itself other than a manual on/off switch ...i.e. a start/stop button ..bells are ringing as to this not been right at all.

As others have clearly made i think you need a competent Electrician in this field and ill go against what the MODs have suggested that this goes in DIY as i believe this is an arrangement and task in hand here shouldn't be advised from DIY level input as the results can be dangerous and damaging i believe having our clear opinion that this will be best done by an Electrician/Engineer familiar with the set up is the best advice youll get. Hope you can see this by the questions this has generated that its not just a simple thing to attempt an answer as we would have to ensure this is actually correct for the job.

You are a panel beater / painter and i commend you enthusiasm at saving a few pence here as well as the wannabe sparkies that have let you down... running back to their domestic jobs lol... but this is one where the Pro's should be involved as this Thread generates more questions than i think you can confidently answer.

 

[rdautobody]

Hi,

thanks for your responses regarding this compressor set up.

that wiring is exactly how i got it from ebay. ive literally screwed it onto the wall and thats how it has stayed.

I am extremely concerned now if im honest and as pointed out i am a panel beater [painter but its not a go at saving money its literally because i've been let down by professionals and now its turned into a cry for help as my bodyshop is at a standstill and i cant paint!

the only visible wiring is the ones going into the switch box and thats all i can say really. I dont know a lot about it if anything at all if im honest , i guess im being a have a go hero!

does anybody know any good electricians near me in northampton that would be capable of doing this?

 

[Darkwood]

You may be better calling a compressor repair company and see if they have an engineer that can connect up your compressor.. this is usually beyond most bog standard sparkies as you have found to your cost... its a shame they cant be up front honest and save wasting your time ... soz i too far away but hope you get sorted

Electrical engineer
Compressor repair company
Compressor suppliers ..... a few lines to try as more chance of a compressor repair company having a competent engineer.

 

[Silly Sausage]

does anybody know any good electricians near me in northampton that would be capable of doing this?

I'm afraid not fella.
All the good ones live north of Sheffield.

 

[Marvo]

I'm afraid not fella.
All the good ones live north of Sheffield.

Or south of the equator


Maybe you can make a new thread in the jobs forum here, state you location and put a link pointing to this thread so any potential takers know what's involved.

 

[Knobhead]

An industrial electrician would have this sorted within an hour.

Avoid household electricians like the plague.
The main problem with compressors is the unloader valve (if fiited). You have to know how they work. Get it wrong and they trip the motor.
To be honest I would have a 2[SUP]nd[/SUP] timer for the unloader valve.

Sorry I’m too far away to help out.

 

[joel89]

I'm afraid not fella.
All the good ones live north of Sheffield.[/QUOTE

or at sheffield me

 

[Silly Sausage]

I'm afraid not fella.
All the good ones live north of Sheffield.[/QUOTE

or at sheffield me

Sorry Joel, I meant including Sheffield!

 

[Knobhead]

The best lives in Nottinghamshire.

 

[telectrix]

can't argue with that.

 

[rdautobody]

ok so an update

i had two local industrial electricians come out today both funnily enough walked away completely baffled and no progress there.

out of complete determination i decided to go looking with a friend and start looking at the switches and looking for unused and or loose locking terminals'

it was at this point i thought hold on a sec, maybe there was an external emergency stop button fitted, this would explain the circuit being broken for the on/off switch and hence wires poking out of the top of the switch panel.

we then noticed that the middle switch relay had two points on the right hand side of it that were both loose and unused, one was at the top and one was at the bottom. we then discovered that the two loose brown wires fit exactly to these points comfortably with no excess . surely then we think that would control a switch between the on / off and the pressure release .

the wires are all fitting snugly and looks promising. the wire coming out of the reset button was a completely random bit of wire that didn't match any of the wiring at all in the switch box so we removed this and discovered that the remaining blue wire from the pressure switch fits perfectly to this point again with no excess wire.

this has reduced the amount of wires from four to 3, because one was added in for what could possibly have been an emergency stop button.

the second switch in the box that we have fitted the two brown wires to is the only switch that isnt bridged on these points like the other two are which tells me that these wires are now switched lives not permanent lives. this now means we have one switched brown for each switch on the compressor and also one permanent live which should surely now have created a switched circuit.

the compressor is now all wired in as far as i can see and to me makes perfect sense, hopefully when i switch the 3 pahse consumer unit on tomorrow morning the compressor fires into life.

does it sound right what i have found and done?

 

[Marvo]

The more I read this thread the more skittish I get. You still need a commercial/industrial electrician that knows what he's doing. If you wire this up wrong ie one of the remote switches doesn't function then firstly someone could get injured and secondly anything could happen. If the pressure switch isn't functioning you could damage the compressor head or even worse rupture the tank if there's a safety release not working. If the E-stop isn't correctly wired you could end up in court if someone gets injured.

This type of machinery really needs connecting correctly, all the functions both electrical and mechanical need thorough testing and it needs to go through a commissioning procedure to set it up.

I'd say if you just switch this on without going through this process then you're being reckless and negligent and possibly endangering yourself and other people. Please persevere and find a capable electrician.

 

[telectrix]

or you could sell tickets for the switch on ceremony. :earmuffs:

 

[Darkwood]

With the time lost doing your job here you could have bought a new compressor and had it fitted by their own supplied engineers ... no-one on here is going to say i think its sounds right just because cables reach and assumptions are made, you need someone that understands the compressor set-up as well as how a star-delta operates.... these industrial electricians you have encountered are no more than glorified domestic sparks ... thats why i stipulated Electrical Engineer as he will be more akin to the operational side of things and won't walk off at the first hurdle.

A competent Industrial Electrician would not have any problem with this job and even if he hadn't done such a set-up before he would have the intellect to work it out even without any wiring breakdown.... Its a standard Star/Delta starter and you need to integrate the compressor controls into it it so once you hit start it is auto-mated and when you hit stop it won't allow the pressure switch to auto-start it again.

It seems you live in a county of numpty industrial sparkies...

 

[Lucien Nunes]

A competent Industrial Electrician would not have any problem with this job

Agreed 100%. It's bog standard, but there are also 87 bog standard ways it can go wrong if you put the wires in the wrong holes by not fully understanding the method of operation. I agree that it is often possible to reverse modifications by looking at what 'seems' to fit where, but it's not reliable enough to ensure safety in this case.

 

[netblindpaul]

OP I can do this for you on Sunday & get the electrics working, I can quote you a fixed price plus materials, HOWEVER, the materials will have to be same day couriered to site on Sunday, I guess that you will not like the price though.
This price will exclude any issues with the compressor or the supply circuits.
Noting also that the pics & information that you have supplied to date, indicate that the existing equipment will currently not meet PUWER98 requirements (statute law) for use in a business.
IF you are interested you are looking at circa £3k, plus VAT, payable in advance, plus materials, the invoice for which will be payable in full immediately upon presentation of invoice, please let me know.
Oh, & yes I do expect to be able to get the materials to site on Sunday, but the cost will be yours to bear.
However, as long as the required materials are available, the supply circuit is suitable and the compressor on the end of the control is OK, you will have a working compressor Monday morning.
Now it is only you that can weigh up your requirements, and the loss to your business, however, I know that more than a week of no income, which is what you are suggesting can cripple many businesses.