I replaced three transformer on my air handler on yesterday, the last one ran for about thirty min. then it burned out, I looked at the wiring to see if I had frailed wire anywere but I did not, can anyone help with this problem?

I replaced three transformer on my air handler on yesterday, the last one ran for about thirty min. then it burned out, I looked at the wiring to see if I had frailed wire anywere but I did not, can anyone help with this problem?

It could be the transformer you are using as a replacement is not capable of producing the required VA for the system. I would check this first. Next you will need to check the components powered by the transformer for short circuits etc

Note: Adding a small low voltage designed circuit breaker or a fuse holder and fuse will prevent you from burning out the transformer while you are servicing the system. The fuse is cheaper than the transformer.

It could be the transformer you are using as a replacement is not capable of producing the required VA for the system. I would check this first. Next you will need to check the components powered by the transformer for short circuits etc

Note: Adding a small low voltage designed circuit breaker or a fuse holder and fuse will prevent you from burning out the transformer while you are servicing the system. The fuse is cheaper than the transformer.

What type of fuse would you recommend?

The problem could be a short in the low voltage wiring to the compressor or to thermostat.
Could also be shorted windings on one of the relays/contactors coil.
I take it does it on cooling will exclude the heating relay.
Leaving Blower or Compressor Contactor/relays.
What is the VA of the transformer.
May just need more VA's

My transfomer I have is - JARD CLASS 2 50/60Hz
TF402424-B51C84 K
PRI WH BK RD OR
B-10 COM 120 208 240V
SEC BL-COM YW-24V 40VA