[Shop-talk] Mystery of the blown transformers

[Randall]

From: Jim Stone [mailto:jandkstone99 at msn.com] 
	
>	Alternatively, I wonder if this one would do the trick:
>	
>
http://cgi.ebay.com/NEW-24-V-40-VA-Control-Transformer-Heating-Thermostat_W0
QQitemZ220206175461QQihZ012QQcategoryZ53296QQssPageNameZWDVWQQrdZ1QQcmdZView
Item
	
>	Its not quite as powerful, but would certainly be easy to install. 
	
I'm always suspicious when transformers fail; as normally they should last
nearly forever.  Going down in rating for a transformer that failed for no
apparent reason seems like a bad idea to me.

At the very least, I would want to check the actual load.  A typical 1156
brake light bulb is rated for 2.1 amps, and 24 volts times 2.1 amps is
50.4va.  But it's not unusual for a "24v" transformer to put out more than
it's rated voltage (especially if the line input is above the minimum
voltage, which it usually is), so the actual power may have been even
higher.

Caveat : If you mentioned what bulbs it has, I didn't notice.  I'm just
guessing that it might be a pair of 1156 as they are very common.  But the
point is that the original 50va unit may have already been overloaded, so
the 40va would be even more so (and hence prone to early failure).

Randall