Compressor help needed

[junkyardgenius]

My compressor has been set to cut out @ 115psi then cut in again @ 80 psi. Lately when it,s started up it only gets to 40 or 50 psi and starts to struggle (motor slows down)and won,t go any higher , sometimes it works ok but most of the time it won,t. Today we took the head of and gave it a clean up and fitted new valves, fired it up and it got to about 80psi and that was it , drained it down and tried again , straight up to 115 no problem , cut in and out ok a couple times then wouldn,t go past 50 psi again.Anyone know whats going on here?

 

[tigler]

Can you provide infromation on the make and model of compressor with pics if possible ?

 

[junkyardgenius]

here tis. no model number. The plate on the motor is gone too but I,m sure it,s a 2kw motor.

 

[ford34/2]

cutting out

Hmmmnnn,
Pressure cut out switch, sticking not working right??, pressure gauge reading correct??

Stan

 

[shenion]

Could be the motor run capacitor getting weak.

 

[tigler]

When it reaches 40-50 psi and struggles, does it continue to run and slow down without the pressure going any higher ?

 

[junkyardgenius]

When it reaches 40-50 psi and struggles, does it continue to run and slow down without the pressure going any higher ?

Yes thats whats happening & the motor slows right down and stops turning but does not cut out.

 

[tigler]

Does sound like a motor fault. If it's a single capacitor motor than very likely the cap is failing. If it's a twin capacitor motor it could be the centrifugal switch inside the motor.
Just make sure there are no loose connections too, before delving too far !! Look inside the motor terminal box and pressure switch for loose wires and terminals.

 

[junkyardgenius]

Thanks for all your help. I,ll have a look at it tomorrow when I surface.

 

[roofman]

might be my eyes or just muck on the unit but zoom in to 200% and it looks like the cap is burnt on the right hand side

 

[tigler]

Could be, or overspray maybe ?

 

[eil]

Good old motors I have one on my T30, the terminal cover is molded to the shape of the Caps, it used to be understood that brookes made that type a certain hp rating and just put on different overloads to whichever hp motor you wanted, so you could effectively up the motor from 2hp to 3hp by just changing the overload.you can wire them in three or single phase. What`s the condition of the belts on it.

 

[junkyardgenius]

O.K. here we are 3 days into 2012 and I,m up for dumbo of the year allready. Took the guard off to take the motor off and noticed the belts were quite slack, tightened em up and everything works ok. Just out of intrest slackened the belts off again and when it reached 50psi the motor stopped again so retightened the belts and everthing,s fine. Doesn,t make sense to me but hey it,s working ok now .

 

[brightspark]

O.K. here we are 3 days into 2012 and I,m up for dumbo of the year allready. Took the guard off to take the motor off and noticed the belts were quite slack, tightened em up and everything works ok. Just out of intrest slackened the belts off again and when it reached 50psi the motor stopped again so retightened the belts and everthing,s fine. Doesn,t make sense to me but hey it,s working ok now .

when its up 2 50psi and the belts are slipping then suddenly bite the motor has to try and restart the pump underload at speed when only the running windings are engaged. hence the stalled motor .only when it stops the starting windings engage through the centrifugal switch giving the extra starting power

 

[junkyardgenius]

Thanks very much for that info. I was going nuts here trying to work out what was going on Should sleep ok tonight, thanks again

 

[Nomolos]

Out of curiosity as I seem to be having a trip every time I start or I should say try to start my compressor, what size capacitor would you need for a motor that size? Tried looking for a data plate on mine but there is a little patch of aluminium oxide where the plate used to live :P

 

[brightspark]

Out of curiosity as I seem to be having a trip every time I start or I should say try to start my compressor, what size capacitor would you need for a motor that size? Tried looking for a data plate on mine but there is a little patch of aluminium oxide where the plate used to live :P

a good place to start is what size trip or mcb is feeding the comp and if its a mcb what type is it a b or a c type and what horsepower motor .the capacitor will have nothing to do with it

 

[Nomolos]

The motor is similar in size to the compressor pictured on page one, can’t find my camera lead at the moment, so a pictures a tad problematical, the trips marked as a B40 , it was originally for a 15kw electric shower but plans changed and it ended up being the garage feed instead its hooked into a 16a plug and socket, I have taken the cap off and there is a distinct “rattle” from within, it’s looking well past its best, it was working fine 6/7 months back but not needed the compressor until now and typically now is when it decides it wants to be difficult

 

[brightspark]

The motor is similar in size to the compressor pictured on page one, can’t find my camera lead at the moment, so a pictures a tad problematical, the trips marked as a B40 , it was originally for a 15kw electric shower but plans changed and it ended up being the garage feed instead its hooked into a 16a plug and socket, I have taken the cap off and there is a distinct “rattle” from within, it’s looking well past its best, it was working fine 6/7 months back but not needed the compressor until now and typically now is when it decides it wants to be difficult

what size breaker is feeding the 16 amp socket. surely not the 40 amp. if the motor its fed of a 16 amp breaker that will be 2 small for the starting load

 

[eil]

I take it there is nothing stamped on the cap itself ?.