Dry type 400 Hz transformer

[novakovich]

Hi!
I am interested in technology of production of 400 Hz transformers and I have one question.
I heard 400 Hz is used in aircraft. Why 400 Hz? There are other common frequencies (50Hz,60Hz). Sorry on my English (English is not my speaking language but I am sure You understand me)

 

[4pyros]

400 HzFrequencies as high as 400 Hz are used in aircraft, spacecraft, submarines, server rooms for computer power,[18] military equipment, and hand-held machine tools. Such high frequencies cannot be economically transmitted long distances, so 400 Hz power systems are usually confined to a building or vehicle. Transformers and motors for 400 Hz are much smaller and lighter than at 50 or 60 Hz, which is an advantage in aircraft and ships. A United States military standard MIL-STD-704 exists for aircraft use of 400 Hz power.

google is your friend, from wiki

 

[KMoffett]

Google:400HZ power

Ken

 

[crutschow]

The size of the power magnetics is proportional to the frequency, so 400Hz transformers and motors are approximately six times lighter than those at 60Hz. Obviously this weight reduction is particularly important for aircraft applications.

You could go even higher than 400Hz but apparently that frequency was a good compromise between weight reduction and higher magnetic losses due to the higher frequency.

 

[squishy36]

I've handled 400 Hz stuff that came from World War 2, so it goes back at least that far. I wouldn't be surprised to learn that it was being used in WW1. Nobody has answered the OP's question as to why 400 Hz was chosen, so it will probably take a trip to a library to find out why people standardized on that frequency. It wouldn't surprise me to learn that the military used it first.

 

[4pyros]

Q: What does 400HZ mean?
A: The commercial power producers in the United States (the “Edison” Co’s) provide alternating current (A/C) power for home and industry. This power limits the RPM of the fastest induction motor to a maximum of 3,600 RPM. The maximum speed of a 400HZ induction motor is 24,000 RPM, approximately seven times faster than is possible with a 60HZ motor. This higher speed and the use of higher quality wire and lamination steel make it possible to produce motors with 10 times the power for the same weight and same size as a 60HZ motor.

400 Hz also seems to steam from the generators used at the time. It was vary eazy to make.

 

[Diver300]

The size of the power magnetics is proportional to the frequency

I think that you mean "inversely proportional"

 

[crutschow]

I think that you mean "inversely proportional"

Of course. Thanks for the catch.

 

[Sceadwian]

There is sometimes not an exact answer for why such a frequency/value is chosen. it could have been 300hz, or 500hz, but the standards ended up simply revolving around 400hz, doesn't matter what number was picked within a practical range just as long as it's the only one used. Same goes with 50/60hz power grids, One section of the world decided on 50hz another 60hz, could have been 45, or 70 or any arbitrary value inbetween and still work fine as long as that is the only value used.

 

[4pyros]

I think it was more a mechanical decision back than. Mechanicaly 400 Hz was easier to make without electronics.

 

[crutschow]

I think it was more a mechanical decision back than. Mechanically 400 Hz was easier to make without electronics.

I don't think that's the reason. It's possible to build a mechanical alternator that generates up to 100 kHz outputs. This was actually used for high power radio transmitters in the early days of radio such as this.

I think it's more likely related to high frequency losses in the transmission and eddy current losses in the magnetics at higher frequencies. 400Hz was perhaps a reasonable tradeoff point between these loses and the savings due to the reduced size of the magnetics.

 

[4pyros]

I think it's more likely related to high frequency losses in the transmission and eddy current losses in the magnetics at higher frequencies. 400Hz was perhaps a reasonable tradeoff point between these loses and the savings due to the reduced size of the magnetics.

Yes thats part of it, but back in the day thay did not have electroinics to regulate the frequency, it was done mechanically and the easiest was 400Hz

 

[KeepItSimpleStupid]

Interesting article: https://www.electro-tech-online.com/custompdfs/2011/08/B-Origin20of20400hz20in20aircraft.pdf

 

[crutschow]

Yes thats part of it, but back in the day thay did not have electroinics to regulate the frequency, it was done mechanically and the easiest was 400Hz

I don't see there's anything special about 400Hz being easy to regulate mechanically. It's the generator shaft speed that is regulated and it can be made what you want by the number of poles used for the generator. How did you arrive at that conclusion?