Correct. Esp. if you are starting (additional) idlers after the first one,
as Karl has suggested.
Bob Swinney
"Ignoramus965" wrote in message
...
On Thu, 8 Sep 2005 08:12:27 -0500, Robert Swinney
wrote:
As with any RPC, multiple motor RPC's will exhibit sagging voltage as the
load is increased. Put enough of them on line and voltage drop may not
be
an issue, the same as with single idler motor RPC's.
Can I try to paraphrase what you said? A parallel motor RPC will work
as well as a single motor RPC. A parallel motor RPC would, however, be
easier to spin up than a RPC single motor whose horsepower is the same
as the sum of HPs of motors in the parallel RPCexample. Is that
correct?
i
Bob Swinney
"Ignoramus11916" wrote in message
...
On Wed, 7 Sep 2005 22:59:29 -0500, Robert Swinney
wrote:
Additional idlers brought on line should have run capacitors for best
performance.
That's interesting and a little counterintuitive. That said, I do not
mind doing so if it is necessary.
i
Bob Swinney
"Ignoramus11916" wrote in message
...
On Wed, 07 Sep 2005 19:25:02 -0400, JohnM wrote:
Ignoramus11916 wrote:
I have a rotary phase converter with a 10 HP idler.
If I was to run a serious 3 phase welder, I would need to increase
the
capacity of my RPC. My own thought is to add two more 10 HP idlers
(at
very little cost). They would be switched on (if necessary), one
after
another, after the first idler properly spins up. Once they are
running, I could turn on the load. That's better than one 30 HP
idler
because
1) They do not strain the breakers at startup
2) It would require a lot less starting capacitance
3) I could regulate how much idler power I am using
Does it make sense?
i
It makes sense, but get the welder and use it with the one convertor
you
have now before you make any decisions. I hooked up a 600 amp Lincoln
transformer welder to my 3hp phase convertor and it worked fine at
low
settings, but I could tell the convertor was maxing out around (I
guess)
180 amps. Your 10hp unit should certainly keep up with reasonable
welding requirements.
Thanks. That makes sense. I will try it with the existing RPC. I have
a 7.5 HP motor also, should be easy to "plug in" if necessary.
i
--
|