Hi Dave,

I have not found that the rotary phase converter slows in RPM during high low 
demands as it is still an asynchronous AC motor and is there is no torque 
demand on the motor shaft.  I don't think a flywheel would help here.  If it 
were physically connected to a 3-ph generator it would be another story and the 
15HP motor would look more like a 10HP from a shaft stand point when run from 
single phase.

A larger rotary phase converter would help though.  Sounds like your machine is 
sensitive enough that a 25-40HP rotary phase motor may be be necessary to get 
the impedance closer to that of the grid.  Adding more 3-phase motors to the 
system lowers the impedance of the WYE and helps to stabilize the wild leg as 
demonstrated with the lathe motor.  I'm entertaining the thought of adding a 
15HP motor to mine if I find a cheap one.


Dennis


>  -------Original Message-------
>  From: Dave <e...@dc9.tzo.com>
>  To: emc-users@lists.sourceforge.net
>  Subject: Re: [Emc-users] Commutating Reactor
>  Sent: May 31 '12 09:43
>  
>  You are probably right. When the drive load surges it is likely faulting
>  out on what it thinks is a lost phase or phase undervoltage.
>  
>  It might be interesting is to run this test again and put a clamp on
>  ammeter on each leg feeding your Mill and see how balanced the currents
>  are.
>  
>  I have never really had any problem with my phase converter running
>  loads so I haven't paid much attention to it, but I think I only have
>  run capacitors connected between one phase and the made up phase.   I
>  know I don't have any
>  between both of the two original phases.   I was always more concerned
>  about the current balance between phases than voltages.   The voltages
>  have always been  within reason ( as I recall ).   But then this is one
>  of those things that I don't pay much attention to unless it isn't working.
>  
>  I suspect that the 611 is expecting a stiff power supply - which most 3
>  phase services can provide.  If you have a large pulley you can attach
>  to your phase converter motor shaft to add inertia to the rotor, you
>  might want to attach it.  It would help the motor supply surge current
>  to the 611 drive.
>  
>  Dave
>  
>  

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