400 Hz

[jbolen]

I want to know can you use 200 amp 60 hz circuit breaker on a 400 hz system

 

[mgookin]

Instead of asking if you can use NEC devices on a 400Hz (aviation?) system, why don't you find out what the requirements are for the 400Hz system? I think that's going to yield the correct answer. There are some 400Hz guys on here. Let's see what they say.

 

[petersonra]

many square D breakers have ratings for use on 400 Hz systems. I think Siemens does as well. IIRC, the interrupting capacity is greatly reduced.

 

[big john]

...IIRC, the interrupting capacity is greatly reduced.

Right, there are a number of reasons for the AIC and overall ampacity derating: One of the factors in the interrupting-rating is how long the current of each cycle stays near the zero crossing. For 400Hz these crossings obviously happen much faster than 60Hz so they give the arc much less time to self-extinguish.

Increasing frequency also increases conductor impedance and reduces the amount of force applied to the armature during an instantaneous-trip. As a result the normal current carrying capacity of the breaker must also be reduced.

 

[roger]

Along the lines of what the others have said, for 400 HZ installations I have always contacted the gear manufacturer I intend to use and let their engineering people tell me what I need.

Roger

 

[jtrezon]

I questioned the use of 60Hz breakers on 400Hz distribution during a survey of 3 hangers. The GE sales rep asked me if I wanted the "official" answer or "unofficial" answer...He was basically telling me under the label they were exactly the same.

 

[templdl]

I want to know can you use 200 amp 60 hz circuit breaker on a 400 hz system

While as a beaker applications engineer my application notes indicate in part that a common UL489 breaker requires derating to be applied at 400hz. When installed in a enclosure breakers are to be derated 20%. Thus a 200a breaker would be derasted to 160a.
We used to offer a special 400hz calibration as an option which may not be available today.
In addion the kaic rating on s significanlty reduced.