Transformer use SOLVED

I have a Transformer Class 2 that has an input of 120VAC 60Hz 29W with an output of 24VAC 850mA. Can I substitute this with a Class 2 Transformer PRI 120/208/240 VAC, SEC 24VAC 40VA 50/60 HZ

by stephendilley
March 28, 2020

1 Answer

Answer by Foxx

Your substitute transformer pri 120/208/240 will have several primary connections for the various voltage ratings. You must use the 120v ac connection. Its 40 VA rating translates to 40/24 = 1.667 amps or 1667 ma on the 24v secondary so is well above the 850ma rating of the transformer you are taking out so you should be ok. I'm assuming unity power factor in the ma calculation which is probably a safe assumption since in any case you have twice the ma rating.

ACCEPTED +1 vote
by Foxx
April 03, 2020

Thanks so much! Very helpful. I just want to make sure I was not going to burn up my device using the 1667ma compared to the original 850ma. Thanks again.

by stephendilley
April 05, 2020

This is a common misconception I've seen here. The important thing as far as the load is concerned is the voltage; the transformer amp or ma rating is what the transformer is capable of supplying without burning up. Simply keep the load below this and you're ok.

by Foxx
April 05, 2020

Thanks! I've wired the new transformer up and it works like a champ.

by stephendilley
April 06, 2020

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