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Martin H. Eastburn
 
Posts: n/a
Default RPC and electric motor gurus

I have a "5" hp RPC - it spins up and drives three transformers. The xformers
are held off until I want the higher voltage three phase. The peak inrush current
is just over 50 amps. Naturally the 50 amp breakers hold up nicely. The transformers
drive 6 three phase motors - 3 at the moment - So far so good.

Martin
Martin Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
NRA LOH & Endowment Member
NRA Second Amendment Task Force Charter Founder



Ignoramus7443 wrote:
On Wed, 15 Feb 2006 00:59:09 -0600, Bill wbbright@amaonlinecom wrote:

On 15 Feb 2006 04:59:35 GMT, Ignoramus21707
wrote:


On Tue, 14 Feb 2006 18:36:46 -0600, Bill wbbright@amaonlinecom wrote:

On 14 Feb 2006 11:53:20 GMT, Ignoramus21707
wrote:


On Mon, 13 Feb 2006 22:08:00 -0600, Bill wbbright@amaonlinecom wrote:

On 13 Feb 2006 02:24:35 GMT, Ignoramus8228
wrote:


On Sun, 12 Feb 2006 18:18:07 -0600, Bill wbbright@amaonlinecom wrote:



Ive got a southbend Fourteen lathe. It has the variable speed pulleys
that go to a two speed transmission.

It has a 200 volt 3phase baldor motor. Baldor say that it is rated
for +- 10% on voltage.

I am using a 5 hp idler with no caps running off of 220

If I try to start the motor in high the motor starter on the lathe
chatters before it finally stays engaged. Low speed starts fine.

Aside from everything, make sure that your starter (contactor) runs
off the utility legs, sounds like it runs off leg3.


i

Iggy .... that was it. leg 3 was wired in to the contactor

cool... what are you going to do with 200v issue? Does the motor
perhaps have a standard NEMA frame?


i

Baldor says its good for +- 10% so that says 180-220v . so I am at the
high end. I will run it for awhile and see what it does. It is a
standard frame.

If it is a standard frame, you have freedom to do whatever you want,
replacement 3 phase motors are dirt cheap...

i


Another question.

will two 5 horse idlers start a 7.5horse?



In my RPC, one 10 HP motor easily starts a 7.5 HP idler (which is not
loaded with any mechanical load). I had a test RPC at some point with
a 7.5 HP idler, that started a 3 phase 5 HP Atlas Copco compressor.

i


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