i have a 3 phase ac generator and need help with converting it to single phase output can anyone help this ac generator is a bendix 3 phase 10kv 8000 rpm unit

 

Is that 10kV or 10kVA? At 10kV, things get a bit more interesting... :twisted:

 

on the plate above the number 10 it says k.v.a.
the next thing on the plate says freq 400
next to that it says phase 3
then whight 31.7 lbs then theres an arrow stating diretion

 

Is that all there is on the plate?
10kVA is the power of the generator, it isn't the voltage...

If the voltage isn't on the plate try measuring it...

 

ok this is all the info thats on the tag
i hope this will answer any more questions see attaachment

Attached Images

starter_gen_0817b_1_.jpg (88.8 KB, 623 views)

 

So, it produces 115 / 200 V

How much do you need? if you want 115V connect it in a "triangle" confuguration
Connect it in a "star" configuration for 200V

What do you want to power with it ?

 

id like to try and power my home with it if its possible

 

The data label say: freq: 400Hz, i think this is some aerospace board device. The 3phase with 400Hz optimal for rectifying and you can use the DC power for bulbs, heating elements. You can also loading each phase independently. The 115V 400Hz good for any device with SMPS input.
Universal (serial) motor also can run, but forget the synchron motors.

 

so i need to build some kind of circut to go from the seven bolts that stick out of this ac generator and make it a single phase 120vac or 200vac power supply to like run a refrigarater or big color tv and some lites could this power a whole house if i could spin the ac generator at 8000rpm i need some kind of scematic

 

Hi eyeofthefly,

Its too high a wave(freq) for normal use.
If your house is 220v you could go across two phases,
and feed the lighting circuits only.
Don't use it to feed florries (strip lights),
use it for filament types only.
If your house is 115/110 then you could use one of the legs,
but only at about 3 Kw.
Again, only for filament lights,
the freq is too high for anything inductive or capacitive.
Some other items would work ok,
things that are not frequency sensitive like
an electric kettle (check power)
an electric toaster (unless it has electronics inside, some do)
electric blanket ? maybe
electric cooker ? ... its clock would not work right, check power.

There is no easy way to reduce the frequency from this unit
from 400 Cycles to match normal household 50 Cycles.

As Sebi says,
you might do better to rectify it to DC,
and use that.
That wouldn't hurt any florries, but it wouldn't work them.
That would work your filament lamps ok.
And if the rectifiers are big enough it would work a cooker ok.
DC might damage some items however,
so be careful with any motor driven items,
if they don't work, switch it off quick, and don't try to use it.
If it does work, switch it off after a very short time,
like three or four seconds, and see if you think its getting hot,
if ok, try a bit longer, some motors will run, but overheat.
Some motors will run OK. you'll have to see for yourself.

Before applying it to your house, check all appliances and
fittings are off. Anything left on might not like DC (or 400 C/s)

And there are some laws about switching generators to house
electrics. Sometimes Power Board officials have found cables live
when working on a fault, due to someone running a generator
elsewhere. They get the severe hump about that.
So make sure you isolate.

Best of luck with it, John

 

Well folks, its a generator he's got there. It will provide an output frequency which is directly linked to the RPM it is driven with. It appears to be designed to be driven from a gas turbine, or something like it, at 8000RPM. At this RPM it would put out its plate rated power. There is no law that says one cannot drive it at some lower RPM to get some lower frequency/ voltage/ power out.

One could experiment with that.

I second the cautions given about connecting it to house wiring which is also connected to the power grid. There would be a puff of smoke and blown fuses if the power came back on from the grid while the generator was still running.

If one wants to power frequency dependent devices ( motors, electronic equipment) from a generator one is required to closely regulate the load RPM of the generator which in turn gives a stable frequency output. This means having some tacho feedback to regulate the power of the driving device (engine, water wheel, etc.). It is far simpler to rectify the AC output of this particular generator, as mentioned, and use it exclusively for powering filament type lights or heating elements. No need to worry about frequency in that case
:wink:

 

well thanks for the info on the 400 hertz i wasnt even thinking about that well here is another thought how about the generator powering a c to some hefty diodes to make it dc then to an inverter

 

I dont think it is a wise choice to connect such a generator to the utility grid by way of your house mains. The proper way to do this is to use a "transfer switch" which is an electronic switch that monitors the incoming power and switches generators into the circuit if it detects a failure. Ideally, you (and your local utility) would prefer that you keep your generator isolated from the rest of the grid.

 

Yes, it could work. You need 6 diodes to rectify the AC. Of course, the rectified voltage might not suit the inverter input so you you have more possible complications. I am not sure if inverters are suitable to directly connect to a generator output, usually they connect to a battery bank which in turn gets charged from a generator etc.
Its not so simple, is it? 8)

 

am i getting this right if i turn the generator at a slower speed than 8000 rpm ill get a lower hertz?