# Phase A Matic RPC has less parts?



## Handy (Jul 31, 2013)

Why is it that a 3 HP RPC from Phase-A-Matic doesn't require the large control box, like the equivalent RPC by American Rotary???


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## Ulma Doctor (Aug 2, 2013)

the Phase A Matic is really a simple device, the housing only contains a few parts.
it's design is very simple. it uses 1 starting capacitor and doesn't take up a lot of space.
there are no balancing capacitors.
it is a basic 3 phase motor starter, no bells or whistles....

mike)


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## bcall2043 (Aug 2, 2013)

Ulma Doctor said:


> the Phase A Matic is really a simple device, the housing only contains a few parts.
> it's design is very simple. it uses 1 starting capacitor and doesn't take up a lot of space.
> there are no balancing capacitors.
> it is a basic 3 phase motor starter, no bells or whistles....
> ...



I suspect Ulma Doctor is correct. I have never seen a Phase-A-Matic rotary converter but have seen their static converter. Fellow forum member Charley Davidson has one which I helped him hook up and I just had to peek inside. Photos below show his static converter. The first photo is the tag showing model information. The other photo shows the converter contents, not much there! I suspect they just add an idler motor and call it a rotary converter. No balancing capacitors makes it less costly?







Benny
The Orphanage Never Closes


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## Ulma Doctor (Aug 2, 2013)

Here's a diagram as to how to wire in the converter for a RPC, it has been sanitized to avoid infringement)

http://www.hobby-machinist.com/showthread.php/13159-PHase-A-Blahblah-s-Idler-Motor-Circuit

the Phase A Matic is not actually a RPC, it starts the motor and delivers a capacitor charge should line voltage dips below a preset point.
it is technically a static converter, there is no rotating element to the converter.

A Rotary Phase Converter is a system that starts a 3 phase idler motor on single phase power and has the idler motor running continuously providing the 3rd leg of power. The idler motor is being supplied 2 legs of power during operation. while the idler is spinning the 3rd leg is induced and can be utilized to help start another 3 phase motor or many 3 phase motors dependent on need. 

i hope the info helps out
mike)


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## Handy (Aug 3, 2013)

Ulma Doctor said:


> the Phase A Matic is really a simple device, the housing only contains a few parts.
> it's design is very simple. it uses 1 starting capacitor and doesn't take up a lot of space.
> there are no balancing capacitors.
> it is a basic 3 phase motor starter, no bells or whistles....
> ...



Would it stand to reason that with less parts, there are less items to fail in the years to follow.
Or, are the "bells and whistles" necessary for effective performance?
Why have to make room for a huge control box if you don't have to?


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## GK1918 (Aug 3, 2013)

All I can say is I do not have a problem. Been doing a lot of hole sawing on a mill sometimes a snag and it will stall and smoke the belt.  So there is plenty of power, its quiet, spindle motors and feed motors run cool.


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## bloomingtonmike (Aug 3, 2013)

GK1918 said:


> All I can say is I do not have a problem. Been doing a lot of hole sawing on a mill sometimes a snag and it will stall and smoke the belt.  So there is plenty of power, its quiet, spindle motors and feed motors run cool.



Unbalanced converters can be hell on a motor over time. It is not masked as a unpowerful motor. Unless you are measuing temp on your motor coils/windings or voltage between the poles while you are running the machines you are not seeing the abuse with the wild leg. May work forever for you. Just pointing out that just because you don't see it does not mean that you do not have a problem and that it is good for your motors.

Adding an ideler motor is a little better (what I did to mine) but you should still have run caps in the setup to balance out all three legs under load. 

Look for rick christophersons info on phase converters. Just one doc that is Very informative on balancing converters.


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