3 phase revisited ..sort of

|> I was once thinking about how to make an arc lamp with the light source |> being as small a point as possible, as bright as possible, and powered |> with three phase well balanced. The only thing that seems plausible is |> 3 arc rods at 120 degree angles. | | Someone else thought of this; I have seen a design for an arc lamp | which worked in this way. Whether it was ever built, I don't know. | Most arc lamps also work on d.c. I have used many of them for film | projection, though sadly they are becoming very rare now. There have | been low intensity a.c. arcs, but they are much less common, and give | an inferior light. I think just about all high intensity lamps are | d.c.; the carbons are different, the negative is almost always copper | coated, and smaller than the positive which has a different core | material; in some cases the negative is uncored. The positive is | sometimes coppered, sometimes not, depending on the design of the | lamp, and how the current is fed into it. In some designs the | positive rotates, and is held in water-cooled silver jaws. Cinemas | used either motor-generator sets, or rectifiers, normally three phase, | to supply the d.c. for their arcs.

I guess the motor-gen set would be one way to cut out harmonics currents going back over the power lines. Now they correct for the power factor.

Another of my interests has been in making my own design for a three phase to DC power supply that produce clean DC while having a harmonic free and unity power factor current, done all solid state, and scalable.

On Thu, 4 Nov 2004 02:56:09 -0500 reqluq wrote: |> The OP appears to be in UK, so 220 single phase, or 380/220 star three |> phase. | | nope caribbean.with 110v normally.

What is your three phase configuration? Delta? Star/wye?

I want to show what is considered 3 phase here and how I have the three positives hooked up without the ground.no biggie

consider what would (could) happen IF the power line or transformer were struck by lightning while you were holding the rod.

safety grounds on equipment are a good thing to have.

I agree,the thing is when I was getting the machine the owner said there is no ground hookup with this machine.just the three positive wires. so he doesn't know what he's talking about?

On 4 Nov 2004 05:25:07 GMT, snipped-for-privacy@ipal.net put forth the notion that...

I'm wondering if an inverter-driven welder could possibly still function on single phase, since it's converting everything to DC anyway. I've never heard of that being done, but I do know that some people wire single phase to two of the three inputs in a VFD to get a three phase output out of it. I'd be interested to know if it's possible to do that with a three phase DC welder without burning anything up.

i refer you to the specs, the pictures, and your statements about the unconnected wire.

there is no ground needed to operate this equipment. normally their is no current flowing in safety grounds. the idea is to provide an alternate path to earth other then your body when something goes wrong.

just a suggestion but i would duct tape some cardboard over that temporary hookup to the electrical panel. it might keep critters, broom handles, and accidental fingers out of harms way.

were you able to access the ftp then?or are you assuming how the hookup is?

would this have anything to do with my fridge starting to shock me? a slight buzz when barefooted

this doesn't sound right. You should be getting the slight buzz from drinking the beers from the fridge.

Insulation breakdown. Look for a worn cord. Possibly the motor windings are going. It won't get any better. Is it connected to a grounded circuit?

You should replace it if you can't fix it. Especially if you have kids and SWMBO around.

Good luck,

If the frame/door are not connected to the earth-ground (properly called the 'equipment grounding conductor') then damaged insulation can energize the frame. Check the third prong plug and continuity from it to the frame. Checking the outlet's third conductor for continuity back to the service panel is another idea. If the equipment grounding conductor is shorted locally to the 'neutral' (properly called the 'grounded conductor', note carefully the naming), then a heavy current in the neutral will apply the voltage drop of the neutral to the egc and frame.

Don't delay checking this. Even if you need to hire someone. It could be a sign of a serious hazard.

daestrom

find a known ground (ground rod, all metal cold water pipe, well). take AC voltmeter one probe to ground one probe to equipment. any voltage reading is unacceptable. if voltage is present:

1: pull fuse or breaker for this circuit. 2: pull out refrig 3: unplug refrig 4: get large Styrofoam chest and ice 5: place beer in chest, dispose of remaining perishables 6: call someone for help (but not the person who wired your shop) 7: go to the beach (with beer chest) and take some digital pics for us frozen Yankees

well I think there is a bigger underlying prob afoot here..my video shocked me also..and there is carpet in here, hmm.fridge only shocks if shoes are off.I better get someone to look at this..anything I can check in the meantime to try and troubleshoot or is it too technical? thanks

ok I put the tester on the fridge frame and the ground to the ground in the electrical box and am getting 109 or so volts from the fridge door..damn..electrician on the way

i wonder if i sent you some 5 buckle artics (rubber boots) if they would get there before the electrician?