Convert 400hz to 50 or 60 hz

[poccur]

Hello all, I have a three phase 220v 400hz supply and I want to be able to use it tp power standard 50 or 60hz 208-220 volt three phase motors. Almost everything I have found seems to cover stepping the 60hz upto 400hz but nothing to step it down. I have found a number of drives but they are enormous and unit weight is a factor.
I will need a total of about 10kw across the 4 motors...


I assumed this would be quite an easy solution as sampling down would seem easier than generating extra frequency.

If there is no simple solution then I will probably order custom built 400hz motors.
Do you know of a manufacturer that stocks 400hz motors off the shelf?

Thanks in advance

 

[tmahan]

rectify to DC and invert back to AC. 400Hz is often used because it can rectify to very low ripple AC. A VFD should be able to do this and a 10kW unit is about the size of a shoe box.

 

[mdonner]

If your power source is a gen-set, it will be more cost effective to replace the alterator.
Otherwise rectifying and inverting to 208-220/3/50-60 is a good solution, but bear in mind the inverter current rating: it should be able to source 3xInom + starting current of one motor, assuming only one motor is started at any given time (or use one small inverter for each motor, with common DC bus. Such systems are offered by Rockwell/Reliance, but I am not sure they are offered for such low ratings).

 

[poccur]

tmahan: where have you seen 10kw drives the size of a shoe box? I would really appreciate finding one.
Many thanks in advance
Poccur

PS- thank you both for answering

 

[poccur]

ok sorry..have re-read your post...(60hz input)10kw vfd the size of shoe box...sure no problem...

Its getting the 208v 400hz down that brings the weight issue in for me...If only there was a vfd with a 400hz input....

It seems odd that there are no 400hz down to 60hz ac-ac converters on the market....for the airline industry this would seem to be a useful piece of kit

 

[tmahan]

The input frequecy wouldn't really make a difference would it? The drive in that size range would use a diode front end to convert to DC.

I don't think heating would be much issue because the current wouldn't differ from the 60Hz input case.

 

[peebee]

What is your 400Hz power supply? A UPS?

I agree, a DC rectifier coupled to a 50/60Hz inverter would seem to make sense.

Otherwise, a motor-generator (MG) set might also work for you.

Here's a converter that will do what you want in one shot:

http://www.majorpower.com/frequency/majorfc_3phase.html

, complete with auto-ranging input and 50/60/400Hz output, that was the second hit returned from a Google search on "400:60 hz converter". A search on "aircraft frequency converter" also seems to turn up lots of goodies.

 

[poccur]

Peebee: many thanks for the response ...the 10,000kva unit weighs 750lb

 

[BrianR]

There are two ways of doing this:
1. Use a 400Hz motor coupled to a 60Hz alternator. Works efficiently, but heavy and noisy.
2. Purchase an electronic frequency converter, commonly available from power supply makers. They convert 400Hz to DC then drive a 60Hz amplifier/switcher. Some of them accept almost any voltage any frequency in and give any voltage any frequency out.

 

[tmahan]

Lets check units 10kW as in the first post or 10,000kVA as in the last post.

 

[GusD]

Hello poccuur

The airlines surplus stores should have lots of 400Hz units.I the 10Kw is correct that should be available.If you have 10000kva than it is a different story.Definitely not shoebox size.



GusD

 

[jbartos]

Suggestion: Visit

http://www.georator.com/tri_fc3.htm

etc. for more info

 

[poccur]

Sorry for the confusion...Over enthusiastic use of '0' key....The unit will require about 9kw delivered....I was thinking a ballpark figure of 10kva to allow for power factors....then I managed to type 10,000kva and confuse everything

A 10kw unit will run me 600+ lbs in weight...That puts it right out of the running....It needs to be mobile.....
The idea with the VFD is great...I have contacted the manufacturers and am waiting to find out from them if they will confirm their unit will take 400hz...(if they confirm then I should be able to keep their warranties etc)
If not then I might still do it but will have to provide reliability data to prove it will work long term.

In the meantime, I thank you all for your input and help...

Respectfully

Poccur

 

[Farkel]

Most 400Hz. equipment has been historically used in the aircraft industry on board airframes. You can purchase a drive off the shelf to convert your 400Hz to 60Hz if that is your desire, from Custom Power Technology Inc., Menonmonee Falls, Wisc. 262-253-0880. Unit would be 18.6"x12.6"x9.7".

 

[jbartos]

Suggestion to the previous posting: Also on ships.