A/C Unit draws 50% more power on 50hz vs. 60hz

[Cadence]

Originally Posted by mdsilvers

I have a question. I recently installed a Victron Isolation Transformer and have my boat in Malaysia. Our boat is 120v/60hz standard. We use the transformer to step down the voltage to 120v/50hz.

Our Cruiseair AC water pumps are 120v dual 50/60hz models.

When running our AC units off the inverter, with 60hz, we draw 6amps for the smaller unit and 12 amps for the larger salon unit.

When I switch the power source to the Victron transformer, the power draw increase to 9amps for the smaller units and close to 18/19amps for the larger unit.

I get a similar increase in current when using the microwave—12amp off the inverter and 18 amps off 50hz Victron.

That is a massive increase in power. I understand that the blowers will run slower at 50hz, but I would not have expected a 50% increase in power. There must be something amiss.

Any thoughts would be greatly appreciated.

Out of curiosity. Are you checking the voltage under load not just the amp. draw?