Compressor starting problem

[inchpincher]

My compressor is struggling with it's starting, it'll turn the pumps a couple of times then 'seize' and the motor whines. I usually catch this and turn it off (at the compressor) for fear of damaging the motor, although it did trip the motor the first time cause i didn't know what it was up.

I though the soft start might be broken so dropped the tank pressure down to 50 psi but same problem. I have been running the compressor quite a lot lately using the sandblasting pot. It's spec is a top range 3hp 3 pump 150litre tank, separate 15amp feed and lives in a warm garage.

The pressure switch kicks in about 95psi and fills the tank to 140psi ish. Is this a bit high and been overworking the motor

Thanks in advance,

ps. after turning it off/on/off/on/off/on it will usually get over what ever hill it's trying to climb and run fine But something obviously ain't right...

 

[rtbcomp]

I though the soft start might be broken so dropped the tank pressure down to 50 psi but same problem. I have been running the compressor quite a lot lately using the sandblasting pot. It's spec is a top range 3hp 3 pump 150litre tank, separate 15amp feed and lives in a warm garage.

It may still struggle to start at 50 psi. Does it emit a loud hiss when it switches off when maximum pressure is reached.?

140 psi should be ok for a 3hp unit, although I only run mine to 100.

 

[classicmini]

Get the Capacitor checked out
Good luck

 

[inchpincher]

Hi rtbcomp,

Yep it omits a loud hiss whenever the tank is up to 140psi and also if you turn it off (on the compressor) when it is running. It's probably only done 100 hours from new so it's due it's first oil change, but i drain it weekly and clean the air filters.

When i first received it one of the pump conrod's seized on the shaft and they sent me a replacement rod with gaskets etc. Wasn't a big drama to change it so i might pop that particular pump barrel off and see if it's beginning to deposit ali on the shaft again (i removed the seize with wet and dry last time). But i'd like to think i'd be extremely unfortunate to have this happen twice

Classicmini - I'm not sure how to check the capacitor mate (any advice?) but my hunch is that this is mechanical not electrical especially because once it's off and running it's fine

Bloody thing ran great all day today but i will be painting a scooter next month and i know it'll die just when i've got all my gear on and a gun full of paint

 

[rtbcomp]

If it's hissing then the soft start is working OK.

If the same rod's gone again there may be issues with lubrication or perhaps something bent or not machined quite right? Is it rotating in the correct direction? There should be an arrow on the pump pulley.

 

[classicmini]

Hi rtbcomp,



Classicmini - I'm not sure how to check the capacitor mate (any advice?) but my hunch is that this is mechanical not electrical especially because once it's off and running it's fine

Bloody thing ran great all day today but i will be painting a scooter next month and i know it'll die just when i've got all my gear on and a gun full of paint

That echoes my thoughts 100% until i had the Capacitor checked out and replaced and guess what BINGO.

Some info here

http://www.sawdustmaking.com/ELECTRIC%20MOTORS/electricmotors.html

And Here :- http://forum.doityourself.com/electrical-c-d-c/293209-capacitor-start-electric-motor-failure.html

Hope that helps

 

[inchpincher]

Thanks for the replys guys, turns out it was my fault

When i replaced the rod last year i had put the head on back to front, realised it was wrong and corrected but in the process must had caused some damage to the valve assembly that is between the head and barrel. Anyway it had finally given up the ghost and must have been making an airlock when starting. No real damage done, just a slight discolouring of the piston crown and an £18 hole in the wallet for new valve and gaskets.

Lesson learned

 

[rtbcomp]

It's reassuring when you find a definite fault.

 

[inchpincher]

Even if it does make me look a tit

I like threads to conclude too

 

[Bobo]

Hi all Im a newbie. My compressors an ABAC 150 something or other. Im glad you discovered the problem was the capacitor as this is exactly what mine does only seems to do it in cold weather though, I know the headgaskets not very good either though.