400 hz circuits

[chuckv6]

Does anyone know anything about special requirements for 400 hz circuits? I know that you're supposed to use non-magnetic conduit but what about wire type? Do you need a special panelboard? I'm trying to bid a job at a coast guard base that needs 400 hz power for their aircraft.

 

[Rockyd]

Come Monday morning, I'd be checking with all the suppliers, that are acceptable as suppliers, per the specs, and calling to find out what the manufacturer can do for you information, and equipment wise.

Might want to poke around here for some ideas.

 

[petersonra]

Does anyone know anything about special requirements for 400 hz circuits? I know that you're supposed to use non-magnetic conduit but what about wire type? Do you need a special panelboard? I'm trying to bid a job at a coast guard base that needs 400 hz power for their aircraft.

we do a fair amount of 400 Hz work. Not much different then for 60 Hz. Same wire insulation, basically the same ampacity, except at very large wires.

we use a line of contactors that are just run of the mill IEC contactors that the manufacturer has tested to switch up to 2000 Hz. We derate 10% at 400 Hz, per their chart. coils are whatever voltage you want. We have bought them by the skid load and have yet to have more than a few failures total. About what you would expect on 60 Hz service.

fuses generally have to be up sized a bit as they generate slightly more heat at 400 Hz than at 60 Hz. Buss has some pretty information if you call their tech support line.

circuit breakers work, but the interrupting capacity is reduced. square d has data on this.

the non-magnetic conduit thing may just be their preference.

 

[catchtwentytwo]

the non-magnetic conduit thing may just be their preference.

I did a few Sperry/Unisys mainframe computers in the 80's & 90's that required external 400 hz power, supplied by either by rotary power convertors driven by a 60 hz UPS or 400 hz static UPS systems. The raceways were specified as aluminum rigid conduit or aluminum liquid tight (try asking your local supplier for that).

I was told 400 hz circuits in ferrous raceways had greater voltage drop issues due to edddy currents. Not sure if that is 100% accurate. I did a quick Google today and found this IEEE Abstract .