DIYbanter - View Single Post - Air Compressor Problem

GregS[_3_]

In article , wrote:
On Thu, 18 Mar 2010 15:58:38 -0500, "David"
wrote:

wrote in message
. ..
On Thu, 04 Mar 2010 05:13:31 GMT, lid
(Sparks
Fergusson) wrote:
After reading all the posts, several things stand out.
The most
significant: There is no excessive current draw when the
motor stalls.
By all the laws of physics, that is flat out impossible.
There are
two explanations (well, three, but I'm assuming you aren't
making this
up). The first is slippage at the belt, motor pulley, or
rotor.
Given the knowledge you have exhibited, I say that can't
be the
problem; it's pretty hard to miss the fact that the motor
is spinning
but the belt is slipping.

That leads to only one conclusion: The actual voltage to
the windings
is dropping. Possible causes are a bad thernal overload
protector,
bad run capacitor (some motors hide the starting capacitor
inside,
while the run capacitor is in a cupola on the side), or a
corroded
terminal so only one of the paired windings is used.

All of these possible causes result in a lot of heat
generated at
one small point EXCEPT the single winding and the bad run
capacitor.
The single winding explanation is unlikely because it
would not
deteriorate gradually. That leaves the bad run capacitor.

PlainBill

There is one more possible cause: Some or all of the
windings on the rotor that are supposed to be shorted are
open. An induction motor works because windings on the rotor
are shorted to induce the field needed to turn the rotor.

David

I've never seen that, but it is definitely a possibility and would
also explain the symtoms.

PlainBill

With all the talk, I would have liked to hear the final answer to
the story. Is the compressor working yet. Its
been a long time.

greg