"Ignoramus11522" wrote in message
...
On 2008-08-06, DrollTroll wrote:
Awl--

What's more important when adjusting capacitor values:
Getting equal voltage between each pair of legs, or balanced current in
each leg? Seems like you can't have both.

Equal voltage between legs, means that your RPC has phases that are
exactly 120 degrees apart.

At equalized voltage, the current through the generated leg is through
the
roof.

What exactly current are you measuring, from the generated leg to
load?

Right now, just the idler(s) itself.


At equalized current, if line L1-L2 is 240, then L1-L3 and L2-L3 are
about
230-233, which is not so bad.

On a 10 hp idler, it takes only 50 uF per leg to equalize the current in
the
legs, but much more to equalize the voltage--with the resulting excessive
current in the third leg.

I also noticed that two 5 hp idlers draw much more current than the sum
of
either operating by themselves! And much more than my 10 hp idler.

Idears?


What is your schematic , you can skip contactors and stuff and jyst
post how it is wired when running.

Start caps disconnected when running.
With 240 V coming in to L1, L2, 50 uF (or whatever) connected between
L1-L3, 50 uF between L2-L3.

I wired up a switchable bank of capacitors, dual rows of 100, 80, 60, 25,
25, that can be switched in in any combination to any combination of idlers.
L1-L3 and L2-L3 can have different caps, and usually do for equal voltage.
But as mentioned above, for the equal current state, the caps are much
lower, and equal.

I will be wiring up heater elements (about a 5 A draw), in both delta and
wye configs, to test-load the idler/cap combo's. Hopefully today/tomorrow.
--
DT






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