how do you test a 230 to 120 v transformer?

Answer 1

Make a resistance check to verify that neither of the windings are shorted to the frame or to each other.

Then apply 230V to the primary winding and verify that the secondary winding measures 120V.

Lastly, apply a load equal to the rated load of the transformer across it's secondary and verify that the transformers thermal rise does not exceed its specification.


Doug

Answer 2

With the transformer disconnected from any power supply, connect an ohmmeter across the 230 V leads. It should show a very low resistance. Repeat for the 120 V leads. It should show an even smaller resistance. Connected across any 230V and any 120V lead should show ∞. Last, connect from one lead of each winding to the frame. You should get ∞. Perform these last tests with a Meg-ohmmeter if you have one available.

With the breaker or disconnect off, connect the transformer primary to either 230 or 120 V. Protecting yourself from explosion, turn the circuit on, preferably using a wooden stick. If the circuit protection holds measure the voltages across the primary and secondary leads. The secondary voltage should read exactly half the primary voltage with no load connected. Finally, connect your load to the secondary and measure secondary voltage again to make sure voltage drop with load connected is not excessive.

Answer 3

Using a multimeter do the following checks 1. Check continuity of primary circuit. 2. Check continuity of secondary 3. Check no continuity (ie short circuit) between primary and secondary 4 Check no short between primary and transformer core 5. Ditto for secondary Then apply voltage to primary and check voltage on secondary. If it has a load rating check voltage with such a load applied

Answer 4

Carefully

Answer 5

put power to the 230v side.....if no smoke.....check voltage across the 120v side....should be close to 120v