Outside air conditioner unit blew circuit breaker, sparked ...

Posted by Doug McLaren on October 27, 2009, 5:10 pm

| It is probably not the fan. It's probably the compressor. I'm
| thinking you can't replace the compressor because you probably do not
| have a recovery system and an oxy/acetylene set to braze the new one
| in. But you could surprise me I suppose.

I will not be attempting to replace the compressor myself. The
outside fan, that's easy to get to and I'd try it myself. If it is
the compressor, I'll pay a professional for that.

But in this case, sparks (or just light -- I'm not sure what) came
from the outside unit when it started, seemingly from the motor. The
outside unit seems to be just a fan surrounded by a radiator. (I'm
guessing the compressor is inside.) I wasn't close when it happened
-- but I did see it light up (it was night time, so I could see it) --
which tells me something either emitted sparks, or got red hot before
the circuit breaker blew again.

As I understand it, it's a three phase motor but powered by one phase
power, and the condensor helps this arrangement work. If a motor
can't start, it'll draw a massive amount of current and get hot, fast.
My theory is that the condensor wasn't working properly and so the
motor couldn't start, the winds got red hot in a second before it the
breaker blew. But it's just a theory -- I've little actual experience
with this motor/condensor setup, though I am somewhat familiar with DC
motors. The motor seems to spin freely.

I only have one case of failure to work with, but I'm guessing that
the condensor got wet and that prevented it from working properly so
it couldn't help the motor start. My current plan is to clean the
condensor off, make sure it's all waterproof, and then run with it. I
guess since the motor is outside, with nothing flammable nearby, and
it does have an effective breaker, there's little actual risk of fire
-- at most, it'll fry the motor.

--
Doug McLaren, dougmc@frenzied.us
If Bill Gates had a penny for every time Windows crashed...
.oh wait, he does.

Posted by on October 27, 2009, 6:32 pm

On Oct 27, 5:10=A0pm, "Doug McLaren" <dougmc

+usenet-20091...@frenzied.us> wrote:
> In article <6a9a3e4a-b90f-4820-b53d-9926adb75...@x5g2000prf.googlegroups.=
com>,
> | It is probably not the fan. =A0It's probably the compressor. =A0I'm
> | thinking you can't replace the compressor because you probably do not
> | have a recovery system and an oxy/acetylene set to braze the new one
> | in. =A0But you could surprise me I suppose.
> I will not be attempting to replace the compressor myself. =A0The
> outside fan, that's easy to get to and I'd try it myself. =A0If it is
> the compressor, I'll pay a professional for that.
> But in this case, sparks (or just light -- I'm not sure what) came
> from the outside unit when it started, seemingly from the motor. =A0The
> outside unit seems to be just a fan surrounded by a radiator. =A0(I'm
> guessing the compressor is inside.) =A0I wasn't close when it happened
> -- but I did see it light up (it was night time, so I could see it) --
> which tells me something either emitted sparks, or got red hot before
> the circuit breaker blew again.
> As I understand it, it's a three phase motor but powered by one phase
> power, and the condensor helps this arrangement work. =A0If a motor
> can't start, it'll draw a massive amount of current and get hot, fast.
> My theory is that the condensor wasn't working properly and so the
> motor couldn't start, the winds got red hot in a second before it the
> breaker blew. =A0But it's just a theory -- I've little actual experience
> with this motor/condensor setup, though I am somewhat familiar with DC
> motors. =A0The motor seems to spin freely.

I don;t know what you're looking at or talking about, but all the
residential compressors that I have seen have compressors where the
motor is sealed inside with the refrigerant. It's like a sealed
refrigerator motor. So, you couldn't see fire or sparks from the
compressor motor. It would have to be an external component, ie
relay, starting capacitor, etc, or the wires where they enter the
compressor, etc. Also, if the windings on any motor got "red hot",
then the motor is kaput. It's possible the flash was from the fan
motor.

Also, I would not rely on the breaker giving you protection from a bad
outcome. For example, if something is partially corroded, not making
contact, it could develop enough resistance and generate heat,
starting a fire, without ever tripping the breaker. Or if the unit
is not properly grounded, a partial short could leave the case hot,
etc.

You could do a thorough inspection and you may find the obvious
culprit. With it arcing, one would think it wouldn't be too hard to
track down by visual or smell.

> I only have one case of failure to work with, but I'm guessing that
> the condensor got wet and that prevented it from working properly so
> it couldn't help the motor start. =A0My current plan is to clean the
> condensor off, make sure it's all waterproof, and then run with it.

All the capacitors I've seen could have water poured on them and still
would not matter. They are sealed.

=A0I

> guess since the motor is outside, with nothing flammable nearby, and
> it does have an effective breaker, there's little actual risk of fire
> -- at most, it'll fry the motor.

Probably, as long as there are no flamable items there now or in the
future. I've seen units with plenty of leaves in them and nearby.

Bottom line, I'd make sure I found out exactly what caused this.

Posted by Ralph Mowery on October 27, 2009, 7:36 pm

> In article

> As I understand it, it's a three phase motor but powered by one phase
> power, and the condensor helps this arrangement work. If a motor
> can't start, it'll draw a massive amount of current and get hot, fast.
> My theory is that the condensor wasn't working properly and so the
> motor couldn't start, the winds got red hot in a second before it the
> breaker blew. But it's just a theory -- I've little actual experience
> with this motor/condensor setup, though I am somewhat familiar with DC
> motors. The motor seems to spin freely.
> I only have one case of failure to work with, but I'm guessing that
> the condensor got wet and that prevented it from working properly so
> it couldn't help the motor start. My current plan is to clean the
> condensor off, make sure it's all waterproof, and then run with it. I
> guess since the motor is outside, with nothing flammable nearby, and
> it does have an effective breaker, there's little actual risk of fire
> -- at most, it'll fry the motor.
> --
> Doug McLaren, dougmc@frenzied.us

Not making fun of you, but quit calling the capacitor a condenser.
Especially when talking about air condioners. I don't recall any calling a
capacitor a condenser in many years and I deal with electrical and
electronics every day. A condenser is usually though of as a part where the
refergent goes through.

The motor is not three phase either. It may be a single phase with a
capacitor start.
The capacitor does help it start up.

YOu probably have a fan motor and the compressor will have another motor
inside it. That motor is not replaceable except for the whole compressor.

Posted by Lp1331 1p1331 on October 27, 2009, 8:49 pm

Is that a Trane unit? I have seen quite a few Tranes where the
cranckcase heater shorts out-- and it seems to happen a lot more often
with heavy rain. If so, it is a fairly easy and inexpensive repair.
Larry

Posted by N8N on October 28, 2009, 9:15 am

> > In article
> > As I understand it, it's a three phase motor but powered by one phase
> > power, and the condensor helps this arrangement work. =A0If a motor
> > can't start, it'll draw a massive amount of current and get hot, fast.
> > My theory is that the condensor wasn't working properly and so the
> > motor couldn't start, the winds got red hot in a second before it the
> > breaker blew. =A0But it's just a theory -- I've little actual experienc=

> > with this motor/condensor setup, though I am somewhat familiar with DC
> > motors. =A0The motor seems to spin freely.
> > I only have one case of failure to work with, but I'm guessing that
> > the condensor got wet and that prevented it from working properly so
> > it couldn't help the motor start. =A0My current plan is to clean the
> > condensor off, make sure it's all waterproof, and then run with it. =A0=

> > guess since the motor is outside, with nothing flammable nearby, and
> > it does have an effective breaker, there's little actual risk of fire
> > -- at most, it'll fry the motor.
> > --
> > Doug McLaren, dou...@frenzied.us

> Not making fun of you, but quit calling the capacitor a condenser.
> Especially when talking about air condioners. =A0I don't recall any calli=

ng a

> capacitor a condenser in many years and I deal with electrical and
> electronics every day. =A0A condenser is usually though of as a part wher=

e the

> refergent goes through.

They're still commonly referred to as condensers in an automotive
context. Not sure why...

nate

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Outside air conditioner unit blew circuit breaker, sparked ... - Page 2