Rotoverter Initial Idle Results

[neptune]

Hi Oouthere, and congrats on the work you have done so far. You may be able to find a local model engineer to build a new shaft and bearings for your generator , maybe for nothing if you can "sell" him the idea of this technology. AC motors are not easy to use as generators, but not impossible either. I would say you need a generator capable of at least 300 watts. Look around your local scrapyard. A big DC motor , preferrably a permanent magnet one would be ideal. You may or may not have to use gears, or pulleys as a speed changer. You could load the generator with filament lamps or heavy resistance wire to calculate its output. The motors from scrap electric scooters are OK but rarely exceed 200 watts, and need high RPM.
          A cheap alternative would be to build a "pony brake" and measure the output as Horse Power, and cnvert it into watts. Cheap to make,accurate results. Let us Know how it goes. My business allows me little time to play, but at least I can encourage do-ers like yourself.                                             Neptune

[oouthere]

  Hi Guys,

  Thanks for the encouragement as it really helps when beating your head on the wall!  Wattsup, great job on the switches!  I didn't think far enough ahead to buy two sets of caps so.....

  I've bought out all of the switches at our local Home Depot and electronics store so the second test bank has not been started yet.

  The 12KW generator head can either be wired for 120 or 240 and is rated at 1800 rpm.  This is an industrial size head at perhaps 350lbs so it would be asking a lot for 1.8hp to budge it around.

  As soon as I get a good understanding of the basic components and interactions I'll look into building the extraction circuit....this is a ladder for me so one step at a time.

 
  Rich

[ashtweth_nihilisti]

Note- a sugesiton from Rain

To avoid bigger bangs and death of course such box has to be properly
isolated, also the switches need to be of high quality and switch
knobs als very well isolated. The switches should be able to withstand
quite high peak currents and voltages(possible inductive kicks of
several hundred volts or even thousands volts). The caps inside the
box should have proper 1-10Mohm bleed resistors to bleed off the
residual voltage in disconnected state. This avoids the situation when
at switch turn-on the cap voltage from previous disconnect is say
-300V and you turn it on at the exact moment when the grids voltage is
+300V =>> this results then a very big inrush current to the cap and
possibly the melting of poor switch contacts or weak wires

[wattsup]

@ashtweth_nihilisti

Thanks for the heads up on the security issue.

@oouthere

If your 12kva generator runs at 1800 rpm and your prime mover runs at 3450 rpm, you can try to find a 2:1 ratio oil filled bevel gear (not worm gear) or belt drives and run it that way. The PM will be forcing much less  and at that size generator you are bound to hit pay dirt at one point, as long as you do not ask to much from the generator.

[oouthere]

I have to admit it has been tempting to place the 7.5hp on the 12kw head.  I'll continue my current course as I managed to liberate another 9 switches from Home Depot (crying in the boxes they were!).  I'm so far away from a city while at work it isn't even funny....it's tough finding parts!

I installed the new switches and have about 1/2 of the wiring completed.  Perhaps I can find the caps tomorrow, finish the wiring and get an initial load test this weekend.

It seems mandatory to get a 1kw head!  They are only using a 2hp engine so it would seem the 7.5hp would be able to pull the full load but probably closer to 110VAC instead of 120VAC plus we'd be losing a few hertz as well.  It's all good though!

Rich