Hello welcome to Enots engineering I'm Alan
In today's video I have a problem with my air compressor in the workshop
and we'll be looking at how you diagnose what the problem is
and how to repair it
some people won't know that there is a hidden switch on the compressor
that cuts the motor off when it overheats
and if this has switched itself off and the compressor won't work and you may think that the motors failed
but once you switch the switch you'll come back to life
so let's go into the workshop and see how we do it
I have a problem with my compressor
I've got the power on
nothing happens what happened initially there was some compressed air in there
I switched the power on the motor tried to start and stopped and since then it's not work
so I've drained the air out of it to see whether the motor would start
but it's dead so the first thing to do is check whether the fuse in the plug has blown
I have this screwdriver that has an LED in there and if I touch the end
The LED will light up see if you can see that
so when I'm touching both ends the LED lights up here's the fuse
I'll touch the one side hold the screwdriver on there you can see the light
light up so I know the fuse has a connection it's not the fuse
so let's go straight into the switch to see if there's anything wrong on that
this is a switch unit a screw in the middle
take the cover off
just check the earth
If it's earthed you will see the light just comes on
so I know that the earth was connected to the earth
turn this around
the connections are on this side so the mains in is this one
so by touching the negative wire you see it lights up
Thats the positive negative so they are connected
then we go when the switch operates it press this down
according to the cover it's off when its down
which is there and when its up it's on
so that should be on
plug it in switch it on nothing
so I don't think it's a switch but lets get my other test out
switch it on ohms
so if I short this zero
when it's open circuit it will read read one
zero
If I work the switch it should go back to one
the which is working on the negative
and the positive
switch is working
So that switch is sending the electric through to the motor down here
we've got also another cable I can't see what that does
it's some sort of sensor for the compressed air
I don't know what this does here
I think that's okay the switch so I'll put the cover back on
what we'll do is concentrate on the motor
I've got a little adapter that goes in there
the socket will fit on the on the end
Put this on slow
Take the plastic cover off on this side
Lets have a look what we have
A switch in there that might be it
8 amp that was switched off
remember this is not plugged in here's the plug
so what I'm doing is I'm just doing a probe in each of these wires
that's saying it's on
that's on now before it was off
it may have just activated that switch hopefully
so this side we've got the motor this end is the compressor and the piston
this isthe inlet filter
air is sucked in through here
then compressed and I think he comes
down this pipe along down this pipe into the tank
and this on the end here is some sort of pressure switch
so it looks as if this cutout has operated to save the motor
this is the switch that switches off when it overheats
so what's happening now when I switch it on it's trying to go
But there's something wrong
I can turn that round by hand
that's okay obviously the motor seems to be okay
so I wonder if the capacitor gone
it's just blown the switch again that's the thermal protection I think
so what else could it be capacitor it could be
I'll check this valve on the end first I don't think it's this
that works okay
so it's something to do with this
I don't know wether the valve was stuck and wasn't letting the air through
grease and dirt on there so I'll put that back in
I've just turned it around this is the pipe that goes to the tank
so now I'll switch that switch back on the cut out switch
let's plug it in and see if it will run
There we go
so what had happened was switching it on somehow the motor got jammed
and the cut out switch was activated to stop the power going to the motor
to prevent the motor burning out
but in the instructions for this it doesn't mention the cut out switch at all
so I wonder how many of these have been thrown down the scrap heap
people thinking it's burnt out packed up you go get a new one
the oil tank is on the end
here is where the oils filled
on this end there's a dipstick
check the oil level it's ok
this was made in 1997
It's a one and a half horsepower motor and it holds 25litres of compressed air
That's all the screws back
See if we can get some compression
It doesn't seem to want to work
ok I think this is the problem this capacitor
it's 30uf 450 volts
I've ordered one on ebay cost £5.88 including postage
I can't do anything else with that until I get the new capacitor
just a quick point if just tried starting something with the with the capacitor and he doesn't work
do not touch the terminals because this stores a high voltage
and you could get a shock
what I've done with this one I've just shorted it out
so the voltage in there is very low
let me see what there is in there
If I touch the wire to the meter no voltage
so that's supposed to hold the charge
I'm hoping it that
if it's that we would will be back up and running
well I know that capacitors don't last a long time
The capacitors arrived
That's the new one
30uf 450 volts so exactly the same as the old one
the only difference I can see is this has got four terminals
This has just got two
Right time to try it again
Thats working
Put the cover back on
Screw there
one in there
Turn it around
OK
See what pressure it can get up to
Thats working ok now
So I will put that back in it's position
and connect the air line to it
well that's it for today
I hope that was useful and we'll see you next time
On Enots engineering