Need help determining type of power supply

[invictive]

Hi there,

I have a client in China who purchased all of his appliances in North America and now he needs to get some sort of power supply to run them.

Input voltage is: 390V 3-phase 50hz.
Output voltage required: 120/240V single-phase 60hz.

I have been looking around and it seems I want to get some sort of solid state frequency converter.

Power requirements:

Steam Oven - 240V 15A
Warming Drawer - 120V 15A
Microwave - 120V 15A
Oven - 240V 30A
Rangehood - 120V 6A
Garburator - 120V 11A

I need a device that can be left on all the time and can handle most of the units operating at the same time. I guess it would be wired directly into a North American sub panel.

Any help would be greatly appreciated. I have spoken to a couple of electricians but they haven't been able to come up with anything.

Thanks!

 

[FvM]

I would check in a first place, which devices can possibly work with 230/400 V 50 Hz, which can use 120V 50 Hz from a transformer and which are strictly required to be supplied by 60 Hz. Inspecting the type plates or user manuals should answer this.

If you are e.g. able to operate the oven with 50 Hz (there may be a problem with the fan), the overall power demand for the converter would be considerably reduced.

 

[invictive]

Thanks for your quick response.

I opened up the oven to have a look and a lot of the electronics are labelled as 120V 60hz. No mention of 50hz anywhere. The warming drawer does seem to work with 120V 50hz. I haven't tested the Microwave, but from my reading online microwaves can be problematic when running at a frequency other than what they were originally designed for.

The Garburator and range hood should operate fine on 50hz, although they may be a bit slower I guess.

I am a little hesitant to do too much testing as these are very expensive Miele appliances. (plus I am not in China at the moment).

There is a 120V transformer on site that outputs 50hz, however it is just 120V not 120/240V.

Any ideas?

 

[FvM]

If this is branded equipment like Miele, you also may ask the manufacturer.

I don't know what' the exact mains power in china, if the phase to neutral voltage is between 220 and 230 , it should be good for 240 V as well. In so far you won't need a transformer for 240V / 50 Hz. If the voltage is actually too low, a much smaller 220/240 autotransformer would do.

High power AC/AC converters are e.g. made by Elgar AMETEK Programmable Power : AC Products : Elgar and California Instruments

VFD (variable frequency drive) inverters can be also used, preferably when supplemented by a sine output filter.