question on 3phase rotary converter

Reply

  #1  
Old 01-02-11, 05:36 PM
Member
Thread Starter
Join Date: Jan 2007
Location: USA
Posts: 12
question on 3phase rotary converter

Hi Guys -

I'm purchasing a piece of equipment this spring that has a 10HP 3phase motor on it. I was going to get a 20HP converter panel.

20 HP Rotary Phase Converter Panel

My service in the barn is 200amps. How hard is it to wire a panel like this up? I've wired 220 for a compressor in the past. Is this something that I can do or is this something more suited to an electrician?

Phoenix has a wiring diagram on their site, and it looks fairly simple.

http://phoenixphaseconverters.com/20-HP-WPB.pdf

If I'm reading the diagram correctly, I just need a single 220 input to the panel, and then wire the motor up as shown. I shouldn't need the extra 220 3phase output that is shown (going up to the 2nd breaker out of the panel).

Is this correct or am I completely off-base. any help is greatly appreciated. thanks!
Joe
 
Sponsored Links
  #2  
Old 01-02-11, 07:43 PM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: USA
Posts: 9,393
If I'm reading the diagram correctly, I just need a single 220 input to the panel, and then wire the motor up as shown. I shouldn't need the extra 220 3phase output that is shown (going up to the 2nd breaker out of the panel).
What you are calling the extra 3 phase output that is shown going up to the 2nd breaker is incorrect, it's not extra. It's shown as a fusible switch and you have to connect your equipment or 3 phase panel to the load side of this switch, but a breaker could be used. The motor shown is the idler and is part of the phase converter and not your new equipment and must be there for the phase converter to work. This phase converter requires a maximum of a 100 amp breaker, do you have that much spare capacity in your service?
 

Last edited by CasualJoe; 01-02-11 at 07:44 PM. Reason: fix typo
  #3  
Old 01-03-11, 03:37 AM
Member
Join Date: Mar 2006
Location: NE Wis / Paris France{ In France for now }
Posts: 4,808
How big is your exsting service you have there at your place ?? and you have to be aware with 10 HP tri phase motor with phase converter can pretty much push the 200 amp service to limit espcally with POCO transfomer.

If you have 400 amp service and larger you will be fine however check with POCO due some POCO may have policy with larger motor load and how often you will run it.

And with phase converter you have to be carefull with manufactred phase this phase you can not use with line to neutral loads due the voltage from manufactered phase will run anywhere from 190 to 208 volts depending on set up. the Line to Line will be fine.

Once you give us the basic answer we will go from there.

Merci.
Marc
 
  #4  
Old 01-03-11, 06:57 AM
Member
Thread Starter
Join Date: Jan 2007
Location: USA
Posts: 12
Hi Guys -

thanks for the replies. I guess I don't fully understand the whole phase converter thing. What does the idler motor do? Is that what is actually creating the 3 phase power? (gotta forgive me, I'm a mechanical engineer, not electrical )

I have a 200 amp service in the barn, 200 amp service at the house and a 100 amp sub-panel in my shop (coming off the house breaker panel). The barn only has a pair of breakers (20 amp) active (lights and an outlet). I can actually disconnect one of the outlets since its no longer needed, so the panel is basically free.

thanks
joe
 
  #5  
Old 01-03-11, 07:24 AM
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,399
The phase converter panel you linked to is just a collection of capacitors, an input circuit breaker, an output circuit breaker and a starting relay. It needs an 20 hp. three phase motor to actually output the three phase power to your new tool. The motor acts as a rotary transformer approximating a three phase output from a single phase input.

Unless you plan on having more than the one machine running constantly on three phase power you do not need to oversize the converter panel and idler motor. The whole assembly can be sized to the largest motor to be run and smaller motors, if run intermittently with the large motor will most likely be fine, depending on how hard the individual motors are loaded.

What kind of machine are you getting? It may be that a simple rewinding of the motor along with a static phase converter would better suit you than the rotary converter. Give me some details and I can better advise you.
 
  #6  
Old 01-03-11, 09:50 AM
Member
Thread Starter
Join Date: Jan 2007
Location: USA
Posts: 12
The piece of equipement is a 200mm pellet mill. The mill is powered by a 7.5KW, 3phase motor (I don't have motor specifics unfortunately). It will be the only piece of equipement running off of this converter.

I debated about using a static converter versus the rotary, but I can't have the decrease in HP (and corresponding torque) that would accompany the static converter. The mill requires gobs of torque to function properly.

thanks for the help
Joe
 
  #7  
Old 01-04-11, 12:29 AM
Member
Join Date: Mar 2006
Location: NE Wis / Paris France{ In France for now }
Posts: 4,808
If this machery started unloaded the static conveter may work ok but with loaded start the rotary can handle it much better than static conveter and however most small VSD { variable speed drive } can have either single or three phase input while the output is three phase so it will not be a issue.

The mid size VSD and larger one it will depending on manufacter specs some case they will have two rating one for single phase supply and other rating for three phase supply.

Merci.
Marc
 
  #8  
Old 01-04-11, 03:58 AM
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,399
IF, and at ten horsepower this could be a big if, the motor is a wye-connected dual voltage model then it can be re-connected (will probably require internal wiring additions) to allow a static converter to give 100% power output.

I have made several static converters for air compressors, lathes and milling machines and never had a problem with either starting torque or full load power. I have also made one or two (can't remember, it has been around thirty years ago) rotary converters and never had any problems.

With the static converter you MUST re-connect the internal coils of the motor with running capacitors in a certain order to get 100% power, without doing the internal re-connect you will only get about 60% to 75% power without severe overheating. Re-connecting the motor is not a real difficult job but it does get a bit involved and requires soldering skills. It can be done by any decent motor repair shop if you don't trust your own skills and it does not damage the motor in case at some future time you want to revert back to a genuine three-phase system. I detailed the re-connection procedure a few months ago but the original poster at that time never returned to have me detail the converter itself.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes