60 Hz to 50 Hz frequency transformer/inverter

Question

I need to transform the frequency from 60 Hz (220 V) to 50 Hz (220 or 230 V). Alternatively I can use 110 V, 60 Hz for the required output.

I'm looking to find a cost and space effective solution. It is for a build-in coffee machine and build-in microwave appliance bought in Europe (max. 1 kW each, can be always used separately). What would do the job?

I've seen normal transformers just change the current 110/220 V and vice versa, but leave the frequency the same. Since I already have a 220 V power supply I just need to change the frequency, what appears to be not that easy. I also wondered if there would be anything in the appliances' insides that would be cheaper to change, but probably that's not the case since these models would not have US counterparts, although both are Whirlpool.

The biggest problem is the micro, since the coffee machine works, but is a bit 'slower' than it should be.

Can anyone help?

Answer 1

Both your machines use transformers inside to create the required working voltage. Using transformers at 60Hz designed for 50Hz will be no problem. Using one at 50Hz when designed for 60Hz is more troublesome, as the max flux inside the core will be greater than designed.

So for you 60Hz 220-230V is fine. But the electronics inside that measure time were built for 50Hz, so at 60Hz they will run faster. Many electronic clocks use industry standard chips which can be set to either 50 or 60 Hz by soldering a certain pin to ground or not.

Use them, don't worry, just don't trust the clocks.

Answer 2

If the clocks are the main issue, as I do agree with the other answer, you might simply get a small outlet timer. One used for Christmas lights would work well. It would allow you to have the unit turn on or off in the correct times and is very inexpensive compared to most other solutions.

Answer 3

With motors and transformers, the limit factor when moving from 60Hz to 50Hz is is normally "V/f" which relates in a hand-wavy fashion to the amount of magnetic energy that can be stored in the iron cores before saturation.

Where motors are built into expensive equipment, and the speed change isn't an issues, a common approach is to use an auto-transformer to reduce the voltage to maintain the V/F value.

For instance I got a very nice Helium compressor (at a bargain price) to use with a cryogenic setup, but it was only rated for 60Hz 220V (V/F = 3.67). By reducing the 240V 50Hz line to 185V I maintained the same V/F and it runs without problem. Given that the cold head was also designed for 60Hz but run at 50Hz, the reduced compressor output was matched by the reduced consumption.

Whether this works with transformers depends on the voltage required to maintain V/F matches the equipment input range.