[TheForge] Fwd: Shop tools & layount (3-phase converter)

[James Binnion]

>For a phase converter, don't you need the same size or larger motor than the
>one you're trying to run in the first place?  Seems to me that the power
>used would overcome the initial savings on the motor.
>
>Please tell me what I am thinking wrong.

The  big advantage of a rotary over any other type of phase converter 
is the ability to support multiple motors, you need a dedicated 
converter for each motor for the static or solid state types. 
Actually you can run more motors than the nameplate HP on the 
converter motor. The nameplate HP on the converter is the largest 
motor you can start. However you can run as much as 3 times the 
nameplate HP  simultaneously so if you have a 5 HP converter motor 
you can run 15 HP of combined motors but could not start a 7.5HP 
motor. So you can run a whole shop off of one converter as long as it 
is sized properly. The converter motor is not under any load so it 
has less heat build up this is why it can support more than the 
nameplate  HP in combined motors.

The rotary converter is acting as a rotating transformer so the only 
losses are really wire resistance and iron core losses both of which 
are less than the static phase converter losses also the static phase 
converter will only provide about 2/3 of the power output of your 
load motor so a 1HP  motor running on a static type converter will 
only put out 2/3 HP while a rotary converter  supplied motor will put 
out full nameplate HP.

Jim Binnion
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