Compresser blowing fuse

[angellonewolf]

Going back to an old compressor project I finished the compresser turned on and ran fine but keeps blowing Fuses (not triping the electrics but has done once mcb rated 16amp)
Was not blowing Fuses before runs for a while more 30/40 seconds on first start up but after might blow right away if needs to restart

I have now noted the motor is rated at 14.5 amps am assuming this is the normal for this but was running on 13 amp for a long time before ?

Any chance the oil got thick in it ? Or am I just being stupid and at 14.5 it's never going to run ?

 

[angellonewolf]

 

[AVI_8]

If presumably the wiring is all correct, check the capacitors

 

[angellonewolf]

Wiring is fine I took photos before I took apart and double checked them the capacitor could be gone I guess but normaly does or at least did run before been in the garage for quite a while now but can't belive I spent all that time to find it don't work

 

[AVI_8]

Does the pump turn normally with the belt off, also does the motor run with the belt off?

 

[waddycall]

Have the pulley sizes changed?

 

[julianthegypsy]

There's normally a valve to release pressure between the cylinder and the tank to reduce the load when it starts up. If that is stuck its trying to start up against a full load and will blow a fuse.

 

[angellonewolf]

Does the pump turn normally with the belt off, also does the motor run with the belt off?

Have the pulley sizes changed?

pump turns fine at least you feel the build of compression and then drop as goes round

yes pump and motor runs when not connected to the tank though i did not try it for long a min aprox a 60 secs

when the motor was on the bench after a pully change both where 120mm so no change there and run fine again for 30 40 secs as was not bolted down but did not move that much any way

 

[angellonewolf]

There's normally a valve to release pressure between the cylinder and the tank to reduce the load when it starts up. If that is stuck its trying to start up against a full load and will blow a fuse.

just replaced the fuse and tryed to start it again run for a few seconds and there goes the fuse again it not been started for over a week and tank showing empty so im assuming thats not the problem ?

 

[Brad93]

Check the Capacitors and the pressure valve first. You'll need a multimeter for the caps that can read capacitance.

Could be a number of wear and tear related items increasing the load on the motor causing it to pull more current.

The piston could be dragging on the cylinder, rod bearing on its way out, motor windings failing, has it got oil in it?

Have you got a clamp meter? Need to check really how much it is drawing, but you'll need to wire it up to a 16A plug so it doesn't keep tripping the fuse.
If over 14.5A then you're gonna damage the motor.

 

[angellonewolf]

how to test the pressure valve ?

the capactor i might beable to test ive got a mulimeter with capactance on but will have to cheak on how to use it as never used that one and its got a few plugs for differant mesuments

i think i cheaked the oil before and was up to the oil fill level i did note it was well dirty black no foam etc

yes got a clamp meter but not sure it will run for a time to cheak the amps on it

 

[knighty]

is the tank up to pressure when you're testing or is it empty?

(try it with it empty, and lave it open so it's blowing the air straight out

 

[angellonewolf]

First pic I think I'm measuring this right
2nd pic to test a known capactor

3rd pic the capactir out the compresser

Looks like the capactor now showing right this blow the Fuse ?

 

[angellonewolf]

is the tank up to pressure when you're testing or is it empty?

(try it with it empty, and lave it open so it's blowing the air straight out

It was empty when I first tryed it this afternoon as not been played with for a week at least and gauge showing empty as well


Might try this but what feed back on the capactor first looks out of spec to me

 

[Red'n'Black]

It was empty when I first tryed it this afternoon as not been played with for a week at least and gauge showing empty as well


Might try this but what feed back on the capactor first looks out of spec to me

Capacitor looks knackered to me.

 

[brightspark]

how to test the pressure valve ?

the capactor i might beable to test ive got a mulimeter with capactance on but will have to cheak on how to use it as never used that one and its got a few plugs for differant mesuments

i think i cheaked the oil before and was up to the oil fill level i did note it was well dirty black no foam etc

yes got a clamp meter but not sure it will run for a time to cheak the amps on it

only needs to run a few seconds for a clamp to pick up the amperage but in that time its starting current will be up to about 50 amps then drop to 14 at full speed

 

[m_c]

It shouldn't be pulling 14A until the compressor is reaching higher pressure.
Is it the original motor for that compressor?

 

[angellonewolf]

only needs to run a few seconds for a clamp to pick up the amperage but in that time its starting current will be up to about 50 amps then drop to 14 at full speed

few seconds thats a laugh only had it run for a second and a half befor blowing i dought id even get the time to read it

It shouldn't be pulling 14A until the compressor is reaching higher pressure.
Is it the original motor for that compressor?

id guess it is the original it said interand on the motor that was the make

 

[carbon]

If the first picture with 38 is on the capacitor from the compressor it needs changing as it should be close to 65

 

[angellonewolf]

If the first picture with 38 is on the capacitor from the compressor it needs changing as it should be close to 65

would a 60uf do it there about 7 quid ebay the 65 is 15 ish