Hi chaps got a 240v 15cfm 300lt air compressors which has a fault see if anyone can shed some light on it for me please...

Starting from an empty tank of air ok, switch on bangs licks into action a full chat filling cylinder with air as it should gets to about 60psi and starts to struggle and slows right down to nearly a stand still and eventually builds up speed again and finishes off at 130psi and cuts of again as it should,

After using some air it restarts at approx 70psi and it slow to turn as though its not got enough power in motor eventually fills tank and cuts off, belt is not slipping and its working in a fashion just was thinking the motor is struggling or something..

Any idea's chaps

Is the air filter clean ? i had one that struggled to build up air it was the filter near blocked
Jacko

capacitor dying maybe, has it got a couple on the motor?

air filter

is it a brushless motor? If not, check that they are not worn out...

that little air valve that opens when the tank's up to pressure to allow it to start easier? the motor starts and the valve then closes. maybe needs cleaning? maybe its stuck closed? wouldn't explain why it slows mid cycle though

has to be the capacitors on the motor

is 130 psi a standard cut out for a large compressor

Sounds like a combination of faults, one of which maybe triggered others...

The start up valve mentioned above.

Also the outlet valve in the pump head, if it is not seating properly will allow compressed air back into the cylinder, meaning the piston is forcing already compressed air out through said valve, this is why when the pressure gets to 60 or so psi it starts to slow. Normally the valve would be closed untill the pressure above the piston (and below the valve) is greater than that in the tank, i.e. the other side of the valve, the valve would then crack open and more compressed air enter the tank.

The start / run capacitors, and possibly the motor windings are burning out due to the extra work the motor is doing above 60 psi.

Cheers guys for the input its grafting ok at the moment to be honest just seems to be a bit slow now ??

Have you checked the air filter if blocked that will make it go slow
Or it did with mine
Jacko