Do you think what's disadvantage to 400hz motor against 50/60hz ?, it is copper and power loss is more than 50/60hz motor ?, I think for large industry, if they used 400hz motor and separated generator with 400hz output, I think it can be cost effective

That's my idea long time ago... my client is needs about five dozens of 10HP motor, and I was thinking for make custom request for 400hz motor and generator, but I was abandoned my idea, because I am lack of experience in that area...

Skin depth is about 1/3 at 400Hz. Most noticeable on relays and switches and cable diameters will all need to be bier and possibly hollow f ou are running high current lads. I couldn't imagine having to run hollow cable for a motor.

 

Been maybe over 30 years ago I was involved with the F 15 Eagle generator manufacture and generator control unit manufacture. The technicians referred to the generator test stand as The Screaming Eagle. The test stand ran at 15,000 RPM driving the generator CSD (Constant Speed Drive) box. When you spin something at 15,000 RPM everything and I mean everything must have perfect dynamic balance or really bad things start to happen real fast. For a synchronous AC motor or generator things work out this way. Speed = 120 x frequency (Hz) / poles of the motor or generator. To generate 60 Hz a common 2 pole generator will run at 3600 RPM. The same generator producing 50 Hz will run at 3,000 RPM. With an AC synchronous motor running at 60 Hz will run at 3600 RPM but be rated around 3450 RPM due to pole slips under load. An AC 400 Hz generator having 4 poles so 120 * 400 = 48000 / 4 =12000 RPM and with a good CSD you are spinning that 4 pole generator at about 15000 RPM. When something decides to come apart at 15000 RPM we are back to disaster on an aircraft and really ugly even on the ground. I guess it always comes down to what will work best, all things included, for any given application.

While 400 Hz has some good points reducing transformer size and weight for aircraft systems there are some downsides. Newer on the block are the Inverter Generators where we produce DC and use an inverter to give us AC at a frequency of our choosing but while improving, inverting generators are limited in how much power they can produce. None of this includes loss.

What any of this has to do with:
Why don't we use 40Hz in our electrical supply system?
Totally escapes me but whatever trips triggers I guess. Just keep in mind how frequency effects things like generators and motors. Back to Niagara Falls.

Ron

 

What any of this has to do with:
Why don't we use 40Hz in our electrical supply system?

Nothing.

 

Nothing.

I thought not but just wanted to be sure.

Ron