So what is better? Using a well balanced RPC and all 3 phase motors or
using single phase motors with no balancing caps. As far as the
electric bill goes. With power being metered without the power factor
being metered.
ERS

In article , Eric R Snow says...

So what is better? Using a well balanced RPC and all 3 phase motors or
using single phase motors with no balancing caps. As far as the
electric bill goes. With power being metered without the power factor
being metered.

Because the majority of power is spend doing mechanical work,
I would say that when you are said and done, they will be
the same, within five percent.

Jim


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Eric R Snow wrote:
So what is better? Using a well balanced RPC and all 3 phase motors or
using single phase motors with no balancing caps. As far as the
electric bill goes. With power being metered without the power factor
being metered.
ERS
I suspect the single, 1-phase motor will draw less meterable power from
the mains. It may not be kind to the power company, however. If the
load motor is lightly loaded, or not running all the time, then the
difference gets even bigger, as the phase converter motor will be
drawing meterable power all the time.

3-phase motors are often a bit more efficient than 1-phase, but the
RPC is bound to spoil that advantage.

Jon

On Fri, 09 Sep 2005 20:43:28 -0500, Jon Elson
wrote:

Eric R Snow wrote:
So what is better? Using a well balanced RPC and all 3 phase motors or
using single phase motors with no balancing caps. As far as the
electric bill goes. With power being metered without the power factor
being metered.
ERS
I suspect the single, 1-phase motor will draw less meterable power from
the mains. It may not be kind to the power company, however. If the
load motor is lightly loaded, or not running all the time, then the
difference gets even bigger, as the phase converter motor will be
drawing meterable power all the time.

3-phase motors are often a bit more efficient than 1-phase, but the
RPC is bound to spoil that advantage.

Jon
I was wondering about that. I was wondering if the more efficient 3
phase motors would still use more power, combined with the RPC, than
the equivalent hp in single phase motors. This is because I have to
run my shop with a converter and it seems that my electric bills are
sometimes pretty low when using lots of 3 phase equipment. But I've
never measured it.
ERS