On Thu, 12 Dec 2013 11:59:31 -0600, philo* wrote:

On 12/12/2013 10:48 AM, micky wrote:
A friend with a Panasonic microwave, Inverter model, physcially a big
one, says it is tripping the circuit breaker after about 5 minutes of
running.

They've reset the breaker several times and it's the same each time.

What's your best guess?

I havent' looked at it yet, but my best guess from afar is that some
of the primary windings in the transformer have shorted, and thus the
impedance of the primary has decreased and it's drawing more current
than it should, more than 15 amps. Does this sound reasonable? If
not reasonable, then possible?




They may have other devices on the breaker which they should remove.

That i thought of, but I didn't get a satisfactory answer. The
electric coffee maker is on the same circuit and they've had to unplug
that, but it isn't plugged in now. But when I tried to bring up other
things plugged in to the same circuit, I got some words I didn't
understand.

If there are NO other devices on that circuit and you do not have an AC
ammeter, temporarily try the microwave on some completely different
circuit.

That I didn't think of, and I should have. He said around 3 that
he'd found one, in the paper or online, a lot like this one, and he
was going to buy one today. I told him I would ask online, but he
still went shopping. I read your replies about 5, and after all of
you brought up the breaker, I called and he wasn't home. I called his
cell and got voicemail. I called his wife at home and he was just
coming in but had to go out and had no time to talk!

She told him it might be the breaker and I could hear him say, That's
a good idea"

I could hear him tell her that the new one was in the car. It's safe
enough he can leave it in the car all night, but I have a feeling he
will bring it in, open it up, and cook something, when he gets home
tonight. .

If that circuit breaker blows too, then the microwave may very
well be bad. OTOH: If it does not blow, then the breaker is weak OR the
wiring going to it is loose or burned and getting hot!

I was explaining this to the wife, but she raised something I hadn'ty
thought of, and before I discounted it, she'd was in a hurry and said
goodbye too.

Maybe I'll know something tomorrow, but experience in general tells me
that when someone gets this head up about buying something, he'll buy
it whether he needs it or not.

Thanks philo and all of you.