Compressor cuts out before reaching pressure

[AHTI123]

Just moved my compressor to my new workshop and now it keeps cutting out before it reaches pressure - although not every time. I havnt used it for a while but it was working fine at the last workshop.

There is a small circuit breaker button on the compressor as pic below which pops out, I have to wait a bit to be able to push it in.

I don't think it's because the compressor is being over used as sometimes it happens on the first or second fill.

Any ideas please?

 

[barracuda816]

I would check the motor capacitors and maybe take the belt off to see if it’s all turning freely.

Also as you say it does it since moving it, you are not runnning from an extension or something are you? Check also the voltage at the plug it’s on.

 

[RWD3M]

I think that button is an overtemp protector. Are the environmental conditions any different in its new location?

 

[Martin-Sy]

Check also the voltage at the plug it’s on.

Yes - check the voltage when it's pumping hard. Maybe too much volt-drop in the feed.

 

[tom2207]

check the oil level to start with ,,, no oil turns into heat , thermal trip cuts it out ,,,
is there a hot oily smell
is the air filter blocked
is the fan still attached and moving air , have you blocked the air shroud with anything
shut off the output and try again , in case hoses are leaking faster than its compressing
thats a few to start with

 

[zzr1200]

Also replace the pop-out breaker they're not that reliable, just open the housing there will be the spec for the breaker printed on it.

 

[roofman]

What pressure are you trying to achieve?

 

[mtt.tr]

Is the check valve working? Does struggle to restart?

 

[AHTI123]

I would check the motor capacitors and maybe take the belt off to see if it’s all turning freely.

Also as you say it does it since moving it, you are not runnning from an extension or something are you? Check also the voltage at the plug it’s on.

In the old workshop it was running off a 13A F.S, i thought id do it better this time so it has its own 20A dedicated circuit. No idea how to check the capacitors.

I think that button is an overtemp protector. Are the environmental conditions any different in its new location?

Very similar set up, so dont think its an issue.

Yes - check the voltage when it's pumping hard. Maybe too much volt-drop in the feed.

How do i do this please?

check the oil level to start with ,,, no oil turns into heat , thermal trip cuts it out ,,,
is there a hot oily smell
is the air filter blocked
is the fan still attached and moving air , have you blocked the air shroud with anything
shut off the output and try again , in case hoses are leaking faster than its compressing
thats a few to start with

Oil level looks right on level, ive tried without the air filters, but not any different.

Also replace the pop-out breaker they're not that reliable, just open the housing there will be the spec for the breaker printed on it.

Il get one and try, probably an easy start point

What pressure are you trying to achieve?

The tool im using operated at between 80 and 100psi, im not sure what pressure the compressors usually reaches, but its higher than that.

Is the check valve working? Does struggle to restart?

Actually, now you mention it did struggle to re start twice. Could you elaborate a bit please and point me in the direction of the check valve.

 

[AHTI123]

Thanks for all the replies so far, much appreciated.

 

[AHTI123]

Tried again this morning.

From cold. First fill got to 100psi then the button popped out on the compressor, i pushed to restart it and it struggled to start - like something was seized, so i took the shroud off and turned the belt - it all moved fine. So pushed the button in and it restarted, got to 140 psi and stopped again, third time lucky it then got to 150psi (which is the pressure it gets to).

 

[tom2207]

Tried again this morning.

From cold. First fill got to 100psi then the button popped out on the compressor, i pushed to restart it and it struggled to start - like something was seized, so i took the shroud off and turned the belt - it all moved fine. So pushed the button in and it restarted, got to 140 psi and stopped again, third time lucky it then got to 150psi (which is the pressure it gets to).

10 bar is a fair bit ,,, why not just turn the main pressure down to 120 and it may just be a lot happier most compressors run at 8 bar ,,, 120 psi

 

[dave h 2]

Tried again this morning.

From cold. First fill got to 100psi then the button popped out on the compressor, i pushed to restart it and it struggled to start - like something was seized, so i took the shroud off and turned the belt - it all moved fine. So pushed the button in and it restarted, got to 140 psi and stopped again, third time lucky it then got to 150psi (which is the pressure it gets to).

When a comp gets to pressure and stops you should get a short release of air as the air is vented from the pipe between the pump and tank. This is to ensure the motor can easily start 'off load'.
If the either non return or the blow off valve fails then the motor will draw more power than it should and pop that breaker.
The motor has a start winding which is switched in and out by a centrifugal switch behind the motor fan which operates when the motor spins up to running speed, when this fails/sticks the start winding stays powered, the motor draws more power, gets hot and pops that breaker.

 

[Martin-Sy]

Yes - check the voltage when it's pumping hard. Maybe too much volt-drop in the feed.

How do i do this please?

With a voltmeter if you have one between the brown and blue wires in the plug. BE VERY CAREFUL though. 240V can kill.
You should be seeing at least 220V under load. If you're not confident about doing this get someone competent to help.

Whilst you are at it, if you have not already done so, check the tightness of all the connections including the springiness of the fuse-holder in the plug.
Single phase motors take a lot of current on startup, many times the running current, so any poor joints will be an issue.
Maybe try a new 13A fuse while you're at it.

Perhaps try another 13A outlet if there's one close by in case it's the outlet that's dodgy.

Could you clarify .... In it's previous location the compressor worked fine didn't it?
In it's new location the compressor is plugged directly to an outlet - not via an extension?

 

[AHTI123]

10 bar is a fair bit ,,, why not just turn the main pressure down to 120 and it may just be a lot happier most compressors run at 8 bar ,,, 120 psi

I dont think there is anyway to regulate the pressure, it seems to be pre set? My little compressor that i use for tyres does have a way to regulate the pressure but the ABAC doesn't have a way that i can see.

When a comp gets to pressure and stops you should get a short release of air as the air is vented from the pipe between the pump and tank. This is to ensure the motor can easily start 'off load'.
If the either non return or the blow off valve fails then the motor will draw more power than it should and pop that breaker.
The motor has a start winding which is switched in and out by a centrifugal switch behind the motor fan which operates when the motor spins up to running speed, when this fails/sticks the start winding stays powered, the motor draws more power, gets hot and pops that breaker.

I do get the short release of air once it reaches pressure but obviously i don't when it stops but hasn't reached pressure. The centrifugal switch could be the problem though? SO i'd need to open the motor up to find it?

How do i do this please?

With a voltmeter if you have one between the brown and blue wires in the plug. BE VERY CAREFUL though. 240V can kill.
You should be seeing at least 220V under load. If you're not confident about doing this get someone competent to help.

Whilst you are at it, if you have not already done so, check the tightness of all the connections including the springiness of the fuse-holder in the plug.
Single phase motors take a lot of current on startup, many times the running current, so any poor joints will be an issue.
Maybe try a new 13A fuse while you're at it.

Perhaps try another 13A outlet if there's one close by in case it's the outlet that's dodgy.

Could you clarify .... In it's previous location the compressor worked fine didn't it?
In it's new location the compressor is plugged directly to an outlet - not via an extension?

Thanks, my multi meter is an automotive one and apparantly will only read upto 199volts so thats no use.

Ive wired it into a commando socket and its on a C20 MCB, there is about 18" of 4mm t&e between the consumer unit and the socket. I used to have it on a 13a FS, it worked fine but did blow a 13a fuse very occasionally.

 

[carbon]

I dont think there is anyway to regulate the pressure, it seems to be pre set? My little compressor that i use for tyres does have a way to regulate the pressure but the ABAC doesn't have a way that i can see.

The pressure switch has the adjuster inside (circled in red). With the power disconnected remove the cover and adjust the pressure there. Usually the direction to adjust the pressure is marked.

 

[tom2207]

View attachment 394479

The pressure switch has the adjuster inside (circled in red). With the power disconnected remove the cover and adjust the pressure there. Usually the direction to adjust the pressure is marked.

thats exactly where it lives

 

[AHTI123]

Nipped to screwfix yesterday and bought another multimeter. With the compressor running there is 238V. So this isnt the issue.

I will adjust the pressure as you have advised.

Im going to see if i can find the centrifugal switch as this sounds like a possible.

 

[not done it yet]

Yes - check the voltage when it's pumping hard. Maybe too much volt-drop in the feed.

Noo! Check the power consumption when fully under load. It is that which will overheat the motor and trip the thermal over-load.

Check whether it trips if left pumping at a lower pressure in the receiver?

What is the rating for the motor - continuous or less than? If the pump is faulty, it could be exceeding the service factor of the motor..

Basically, like Tom 2207 suggests.

It needs some sensible diagnosistic checks and the fault will become obvious (one hopes).

 

[Dcal]

The cenrufagal switch will only be a problem on start up, unless the motor stalls and it kicks in again.

The overload push buttons are a godsend for stopping motors burning out. Replace it if you think it's faulty but bypass it at your peril.

The fact the motor pops 13amp fuses would suggest it's drawing too much power, I'd put an AC clamp meter on it and check the current draw during start up and when the fault occurs. A 3hp motor shouldn't draw any more than 17amps after start up but 10 to 12 would be normal for a 3hp compressor.

I'd check the pump.