On Apr 8, 9:05*pm, dpb wrote:
On 4/8/2011 8:44 PM, Tony Hwang wrote:

Steve Turner wrote:
A continuation of the "Why does the 115V-24V transformer keep blowing
on my Trane XB80?" discussion I started on 04/02/2011.

...

... Buy one of hevier one(bigger size and really heavier in
weight than stock) If it blows again, something on the load side is wrong.

I'd venture something is already wrong...

--

Put a voltmeter on the secondary side and measure the voltage when it
is not running. THen turn on the AC and see what the secondary
voltage does. IF it is supposed to operate a relay, and the current
draw is appropriate for the size transformer you have, I would not
expect the voltage to drop by more than 20%. Then leaving the AC on,
for at least 1/2 hour, keep monitoring the transformer tempoerature.
If it is a gradual heating, see how hot it gets. If there is a severe
overload, the transform may blow out before it even gets hot to the
touch. If it just gets warm over 10 - 20 minutes, then that is
probably about normal. IF you can find out what the correct current
drain is supposed to be, I would go for a transformer with double that
amperage ratinbg just ot be ultra-safe. But you have to be there and
monitor things, coming back 48 hours later is not going to work!!!