[Daf11e]

I can't seem to find much info on this scenario, whilst I was driving yesterday my 2000 model went into EAS fault
so drove home before hitting bump stops. (Wasn't far away). After resetting the EAS I found the compressor had burnt / shorted out. I hadn't any leaks and the compressor didn't seem to be overworked, so my questions are..
Do they just fail like this sometimes?
The connector coming from the engine bay has burnt the plastic but the wiring seems ok, so will connecting another compressor be straight forward or should I be concerned?
Thanks for any thoughts.

 

[TheoR]

That's pretty unusual failure in that it's really burnt the connector pretty well.  Chances are, something inside the compressor became stuck causing significant resistance to the electrical current.  <br><br>If the connector on the valve block end is damaged, I would look for a replacement connector.  Then, I would install the new compressor. 

 

[Bolt]

Aloha,
Good to hear you are driving the old gal instead of those "Other cars"
A few possibilities for this:
If you initially had corrosion on the connection, this will cause resistance and, If the voltage drop under load across the resistance is great enough, let's say the voltage dropped to 6 volts during operation, this will cause the motor to run at about half speed, and the current consumed by the motor to double, thus accelerating the degradation of the brushes, brush wires etc.... This can happen in a very short time.....

Alternatively, a build up of carbon dust from the brushes could have caused either the aforementioned high resistance, or an arc internally which will toast the windings and armature.

OR, The brushes were wearing out, arcing, (or as Theo says, sticking) and drawing high current. (This can also melt the plug)

Any of the 3 possibilities can cause a motor to fail and will not, in most cases cause the fuse to blow.

A trip to the wreckers for a new plug, or a bypass connection on the bad pin and the new compressor, and you are good to go for the next 20 years.

Pull the old one apart and let us know what you find?
Cheers!

 

[Daf11e]

Thank you both for the replies,there is a black bar at the bottom which looks broken and plenty of black dust. Bolt I drive the old girl about three times a week and still prefer her to anything else.

 

[Bolt]

The black bar is a brush, and looks pretty knackered. Not close up enough to be sure, but they are not supposed to be in 2 pieces......(2 Brushes, yes)
What does the commutator on the rotor look like (Photo?)
If it is discoloured by arcing, there's the issue. Brushes are gone.
Good news is that if you get some new brushes and clean out the dust, burnish the commutator, and put it back together, it is good to go!

Of course the RR is the fave! Just had to wind ya up!

 

[Daf11e]

Here's a photo bolt......as you can tell I'm not great at electrics.

 

[Bolt]

Well, a side on shot would have been better, but it looks like there is still plenty of copper on the armature, segment gaps are open, and no deep groove where brushes run. All good!
Is there a decent auto electrician, or motor shop in your area anymore?
(Hint: Owner will wear coveralls and have grey hair, if any.....) They can dress the commutator, lube the bearings/ bushings, and put in new brushes probably a 50-90 dollar job and good as new......Or you can buy a new one.......

 

[Daf11e]

Thanks bolt I have an old spare and am making one good unit out of two bad ones....also have one on order which will be here in 7days. Let me know next time your back down under.

 

[Daf11e]

I now have an old one lying around, can you test it with a 12v battery?
Is it red and black not green?

 

[Richard_G]

No, it's green and black. Positive to green and negative to black. Don't put 12V onto the Orange wire, you'll burn out the thermal switch.

 

[Daf11e]

Thanks Richard.

 

[Daf11e]

Thanks for the help guy's I'm back on the road......engine bay plug was ok, just plastic burn.

 

[Bolt]

Great news!
And, now you know all about rebuilding small brushed DC motors!
This knowledge can now be applied to all of them from the Starter to the superlock motors.
Gotta love the free education you get here at the University of RR:thumb:

 

[kapilamuni]

Well, a side on shot would have been better, but it looks like there is still plenty of copper on the armature, segment gaps are open, and no deep groove where brushes run. All good!
Is there a decent auto electrician, or motor shop in your area anymore?
(Hint: Owner will wear coveralls and have grey hair, if any.....) They can dress the commutator, lube the bearings/ bushings, and put in new brushes probably a 50-90 dollar job and good as new......Or you can buy a new one.......

Hi,
You know part no for these brushes/brush holder? or will any generic set of brushes do?

thanks.