2deuce
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What is it commonly used for? There is a mep21c for sale near me, its 400 hz.
Thanks
Thanks
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400 hz
- Thread starter 2deuce
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Radar units. Not much one can do with it...
Boatcarpenter
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Lights and around aircraft and radios because it produces less hum than 60 hz I believe.
rmgill
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I have a radar set for that if you want. 
Aircraft used 400 htz too iirc.
Aircraft used 400 htz too iirc.
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When you use AC power the cycles indicate the passing through zero and to the opposite charge. 60 HZ is fine for us humans since we do not detect this on and off and on cycle 60 times a second. The military went to 400 HZ because the time at zero is shorter between cycles and electronics like this smoother AC especially if you are rectifing the AC to DC it produces a smoother pulsed DC current.
rdixiemiller
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You can use the 400Hz stuff for incandescent lights. I believe flourescents will digest it as well, and produce less hum and heat. If you are making DC, a 400Hz generator would be nice.
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If you are into military radios, there are a lot of aircraft type radio gear that runs on 400hz. You can use it to power your aircraft radios. Ham radio operators that are into the WWII and 1950s-1960s ARC-5, ART-13s, BC-648s, ARC-58s, and other rigs would love to have this genset.
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Be careful with old-skool flourescents, monitor the temperature of the ballasts. The electronic balasts may be ok but the inductive ones can be problematic since they have a certain impedance and reactance depending on the power line frequency. The inductance in series with the lamp is to limit the current. At 400Hz, the current may be so much more limited that the emission-heated cathodes or filaments of the lamps will not have enough current to keep them hot. I've used the screw-in flourescent 'light bulbs' (electronically ballasted) on 400Hz and 800Hz for several hundred hours with no ill effects.
The best advantages of 400Hz power are that the transformers and filtering inductors for it are much smaller and lighter in weight than 60Hz counterparts (about 1/3 to 1/6 the volume/weight) and the capacitors used for filtering in power supplies are also requiring much less capacitance and therefore smaller. If for example you need a 1000uF capacitor in a 60Hz application a 150uF unit will do the same for 400Hz.
You can run some transformer-input power supplies on 400Hz at reduced ratings, -monitor the transformer temperature because depending on the constructuion, it may be quicker to heat up or suffer increased core losses (extra heating caused by the more rapid reversal of the polarity). Most switching power supplies will run just fine such as in computers and the like, but in saying this, I assume no responsibility for any 4th of july celebrations.
How much do they want for it?
The best advantages of 400Hz power are that the transformers and filtering inductors for it are much smaller and lighter in weight than 60Hz counterparts (about 1/3 to 1/6 the volume/weight) and the capacitors used for filtering in power supplies are also requiring much less capacitance and therefore smaller. If for example you need a 1000uF capacitor in a 60Hz application a 150uF unit will do the same for 400Hz.
You can run some transformer-input power supplies on 400Hz at reduced ratings, -monitor the transformer temperature because depending on the constructuion, it may be quicker to heat up or suffer increased core losses (extra heating caused by the more rapid reversal of the polarity). Most switching power supplies will run just fine such as in computers and the like, but in saying this, I assume no responsibility for any 4th of july celebrations.
How much do they want for it?
2deuce
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Its in a GSA auction in Salem, Oregon. Bid is $125 at this time.
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That's cheap enough! how much power?
Boatcarpenter
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MEP-021A
Here is the cover for the TM for a MEP-021A I have that someone gave me. Don't know what differences there are between the A and C models.
BC
Here is the cover for the TM for a MEP-021A I have that someone gave me. Don't know what differences there are between the A and C models.
BC
Attachments
mangus580
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RE: MEP-021A
I am pretty sure the A is the points engine, and the C is the electronic ingition engine.
I have a MEP-021... was trying to fire it up last night to power my halogen lamps for splitting some firewood.... Have I mentioned how I hate 'wrap & hope' engines? Yanno where ya wrap the rope, and hope it starts??
The carb on all these small Mil Std engines are a crummy design. Every one I have, wont start if it sits for any time...
Oh well.... I can always dream of a diesel
I am pretty sure the A is the points engine, and the C is the electronic ingition engine.
I have a MEP-021... was trying to fire it up last night to power my halogen lamps for splitting some firewood.... Have I mentioned how I hate 'wrap & hope' engines? Yanno where ya wrap the rope, and hope it starts??
The carb on all these small Mil Std engines are a crummy design. Every one I have, wont start if it sits for any time...
Oh well.... I can always dream of a diesel
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RE: MEP-021A
Mike that is what Carb cleaner and removeable jets are for
Mike that is what Carb cleaner and removeable jets are for
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RE: MEP-021A
400Hz came about for things that fly. Any electric motor or transformer will be an order of magnitude smaller and lighter for 400 than 60 hz.
i.e., a one horse 400HZ motor is about the size of the old quart oil can, and will have a shaft speed of around 5,200 rpm.
As stated before, a lot of mil commo gear has commonality with aircraft radios hence the need for that power freq. Also, it is a lot lighter to pack & haul.
dg
400Hz came about for things that fly. Any electric motor or transformer will be an order of magnitude smaller and lighter for 400 than 60 hz.
i.e., a one horse 400HZ motor is about the size of the old quart oil can, and will have a shaft speed of around 5,200 rpm.
As stated before, a lot of mil commo gear has commonality with aircraft radios hence the need for that power freq. Also, it is a lot lighter to pack & haul.
dg
Assuming good genset but has a 400hz generator. Is it possible (economically) to modify for 60hz output. Rewind the generator or ______? ?
Have a local fire dept that received a pair of nice 60Kw 400hz gensets (MEP115A). My recommendation is to strip out/sell the engines and sent the rest back to sam.
Have a local fire dept that received a pair of nice 60Kw 400hz gensets (MEP115A). My recommendation is to strip out/sell the engines and sent the rest back to sam.
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Unless you got some 60Hz gennys that have bad motors, the 400Hz's are useless. Get the motors and scrap the rest..
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IIRC some, but not all, of the expansible vans are set up for 400 HZ.
David (I wish I was as good as I once was) Doyle
David (I wish I was as good as I once was) Doyle
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All of my 900 series expando vans we used for BDE and BN TOC's were 60Hz..
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I am thinking that the 400 hz exapando van may have been the Ford 8x8 expansible van used as battery control for the Pershing missile system.....will add this to the things to refresh my memory about.
DD
DD