3 phase power

Reply

  #1  
Old 06-09-06, 05:24 AM
Member
Thread Starter
Join Date: Mar 2006
Location: Annapolis MD
Posts: 21
3 phase power

3 phase power

All

I have an opportunity to acquire some very high quality older woodworking tools (jointer7 hp(knives) and 1 hp (feeder motor), planer 10 hp(knives) and 2 hp (belt), drum sander 10 hp(drum) and 2 hp(belt) all of these tools are 208 volt 3 phase. i am going on the assumption that i cannot get 3 phase power from the poco (even thought the marina at the end of the street has it) plus i believe it would be cost prohibitive to have it installed (underground utilities 2 yards and 3 driveways to the transformer). i was looking for advise on 3 phase converters, how well do they work, what style to go with, sizing, cost of operation, ect.....

if it helps my house has a 400 amp service 2 200 amp (1 with standby generator backup) main panels in the basement 125 amp sub dedicated to the workshop with a keyed lockout (have to keep the kiddos safe) and a 100 amp sub down by the water on the pier. i would prefer to connect it to the sub in the shop thought i could run it off the non generator main panel. i would only be using 1 tool at a time so i do not need to provision for multiple users

tia paul
 
Sponsored Links
  #2  
Old 06-09-06, 03:11 PM
Member
Join Date: Oct 2005
Location: Milwaukee WI
Posts: 1,338
Originally Posted by b0ater01
i am going on the assumption that i cannot get 3 phase power from the poco (even thought the marina at the end of the street has it) plus i believe it would be cost prohibitive to have it installed (underground utilities 2 yards and 3 driveways to the transformer).
You're probably right, and it sounds like you're up on what they would need to do, but hopefully you'll check with them anyway. Maybe they ran spare conductors underground or have duct available.
 
  #3  
Old 06-09-06, 05:43 PM
Member
Join Date: Nov 2004
Location: CA
Posts: 2,041
I found this link on Google:http://www.convertaphase.com/

I don't know anything about them. There are other companies. There is a price list on that website, and they are a little steep!
 
  #4  
Old 06-09-06, 06:50 PM
Member
Join Date: Jan 2004
Location: Oregon
Posts: 1,219
You basically have two options.

1) a 'rotary phase converter'. This is simply a three phase induction motor, with your single phase supply connected to two of the three terminals, combined with protection and starting hardware. It works on the principal that an induction motor will naturally become a generator under the correct conditions. Once the motor is actually spinning, it will run fine with a single phase supply, look like a motor on the two supply terminals, and like a generator on the third leg. The third leg is a reasonably good 'third phase', so the combination of the two supply legs and the third generated leg is a reasonably balanced three phase supply. You need a single phase converter that is sufficient for your largest motor, but once you have this you can actually run several motors at once; each motor acts as a phase converter for the others.

2) variable speed drives. These are electronic devices that generate variable frequency three phase power. The smaller ones can be fed with single phase power, 'small' being up to about 5hp or so. You get the benefits of speed control, but generally have to have one drive per motor, or a carefully planned method of connecting one motor at a time to a single drive.

-Jon
 
  #5  
Old 06-10-06, 11:23 AM
GregH's Avatar
Super Moderator
Join Date: Jan 2001
Location: Manitoba
Posts: 9,668
One thing you may want to look into is whether or not your power utility will allow you to install a converter.
Our utility has had problems with them in areas where there is a high power demand.
A couple of my customers had installed them without permits and had to remove the converter and equipment because the converter would dim the lights when the equipment started.
 
  #6  
Old 06-10-06, 09:01 PM
Banned. Rule And/Or Policy Violation
Join Date: Feb 2006
Location: North of Boston, MA.
Posts: 2,113
Originally Posted by winnie
You basically have two options.

1) a 'rotary phase converter'. This is simply a three phase induction motor, with your single phase supply connected to two of the three terminals, combined with protection and starting hardware. It works on the principal that an induction motor will naturally become a generator under the correct conditions. Once the motor is actually spinning, it will run fine with a single phase supply, look like a motor on the two supply terminals, and like a generator on the third leg. The third leg is a reasonably good 'third phase', so the combination of the two supply legs and the third generated leg is a reasonably balanced three phase supply. You need a single phase converter that is sufficient for your largest motor, but once you have this you can actually run several motors at once; each motor acts as a phase converter for the others.

2) variable speed drives. These are electronic devices that generate variable frequency three phase power. The smaller ones can be fed with single phase power, 'small' being up to about 5hp or so. You get the benefits of speed control, but generally have to have one drive per motor, or a carefully planned method of connecting one motor at a time to a single drive.

-Jon

Go with this (#1 above), several old timers have been running machines on these motors for years. The hardest part is getting the motor started.
 
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
'