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Thread: 400 Hz

  1. #1
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    400 Hz

    Can I use my 60 HZ electrical equiptment on a 400 HZ generator

  2. #2
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    Quote Originally Posted by stjdat
    Can I use my 60 HZ electrical equiptment on a 400 HZ generator
    I'm not sure about all components, but I think anything thing with a transformer will be affected. I used to be an airplane technician for an airline and I was always surprised at how tiny the transformers were. I guess the higher freq allowed them to be much smaller than they would normally be.

  3. #3
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    Simply put no. 50 cycle power OK but 400 no.
    Make something idiot proof and someone will make a better idiot.

  4. #4
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    No transformers, capacitors, inductors, and motor windings would be very upset and most likely let the magic smoke out. However you 400 Hz light bulb will work

  5. #5
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    Resistive loads such as heaters and incandescent light bulbs will work. Fuses and CBs will typically work, although you may have to do some derating, and the interrupting capacity is reduced.

    Most everything else will have issues.
    Bob

  6. #6
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    If you were to connect an induction motor thats designed for 60HZ and turns a little less that 1800 rpm to a 400HZ source, it would try to turn at 12,000 rpm. I say try, because about half way there, pieces would likely start flying off.

    Seriously, most anything purely resistive will work fine. With anything inductive, the design limitations will be exceeded, resulting in catastrophic disintegration of the device.

  7. #7
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    Quote Originally Posted by dereckbc
    No transformers, capacitors, inductors, and motor windings would be very upset and most likely let the magic smoke out. However you 400 Hz light bulb will work
    dereck -

    Tell me why 60 hz transformers would not work.

    When you say "capacitors, inductors" I'm not sure what you have in mind. As far as I know, caps and coils work up into the gigahertz range.

    As for motors, assuming you want 3000RPM. You just need an eight pole motor.

    The biggest problem I know of is 60 hz xfms, reactors, motors have way more iron in them than they need.

    carl
    Using the code for a design guide is a sign of incompetance

  8. #8
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    Quote Originally Posted by micromind
    ... it would try to turn at 12,000 rpm. I say try, because about half way there, pieces would likely start flying off. ...
    One of the first VFD clases I went to in the mid 80s, our test motor was a 2 pole 1/2 hp. The drive would go to 200hz. The first thing we did was program the drive to 200 hz, max ramp rate. The second thing we did was program the drive to reverse from 200hz CW to 200 hz CCW at max ramp rate. Other than having to stand on the motor to keep it from flipping over, it ran fine. At 12,000 rpm, the cooling fan sounds a little like a siren. And I suspect the windage and friction probably sucked up more than the 1/2 hp.

    I didn't say it was useful, or would last longer than minutes, I just said it did it.

    carl
    Using the code for a design guide is a sign of incompetance

  9. #9
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    Quote Originally Posted by coulter
    Tell me why 60 hz transformers would not work.

    When you say "capacitors, inductors" I'm not sure what you have in mind. As far as I know, caps and coils work up into the gigahertz range.
    The reason is because of a force called reactance. Frequency has a drastic effect on both inductive and capacitive reactance, and reactance has a drastic effect on the impedance of a circuit. Impedance is basically what it sounds like, it impedes the flow of current much like resistance does in a resistive circuit such as a light bulb or a heating element. When you go from 60 hz to 400 hz the inductive reactance increases by over 6 1/2 times and capacitive reactance will decrease by the same factor. Basically what this means is that inductive and capacitive circuits have to be designed for the frequency range they are used at. A tiny coil of just a few turns may represent a very high impedance to a 2 gigahertz frequency while the same coil would look like a short circuit at 60 hertz. An iron core increases the inductive reactance of a coil, if you don't believe this try leaving an AC solenoid coil powered up without its "plunger" in place and you will likely have a meltdown. 400 hertz transformers need less iron and shorter windings than 60 hertz transformers of the same power, this is why they are smaller.
    Variable frequency drives first convert the power to DC and then "invert" it back into AC, therefore many of them will accept a 400 hertz supply. This may be an option if you need to run a 60 hertz motor from a 400 hertz generator, however not an inexpensive option.:smile:
    Hope this was helpful.
    Altis

  10. #10
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    If you apply a 60Hz transformer at 400Hz, then the flux developed in the core would be greatly reduced for a given operating voltage. The transformer would probably work reasonably, with the increased hysteresis losses balanced by the reduced flux density. Such a transformer would be far larger than a proper 400Hz transformer of the same KVA rating.

    A 60Hz contactor applied at 400Hz would probably not pull in. If you applied enough voltage to get it to pull in, then it might work accepably, or it might overheat.

    A 60Hz motor applied at 400Hz would require higher voltage in order to achieve proper saturation. It would probably overheat from the increased core losses, and would certainly suffer from accelerated mechanical wear if not catastrophic failure.

    Some rectifier input supplies (computer power supplies, VFDs, electronic ballasts) can operate at up to 400Hz. This will cause increased rectification losses and could cause problems with power factor correction circuitry. Most rectifier input devices are not rated for this sort of use.

    -Jon

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