RE: [CAD_CAM_EDM_DRO] 3 Phase rotary converters

I made those things many years ago. It's much easier now because you can go
to a supply house for commercial HVAC work and ask for a "Compressor Starter
Booster". It's a package with a voltage sensitive relay and a cap. They
use them for kicking over 3 phase refrigeration systems that have a weak
leg. $25 will get you a 5 hp unit. Using the cap method for motors larger
than 7.5 hp is questionable. I did a 30 hp unit and browned out the
neighborhood on every start. The mercury vapor street lights would go out
and everyone's TV screen would shrink for 2 seconds. I never knew what the
current was, it went off scale on my meter.

G. Jackson

-----Original Message-----
From: CAD_CAM_EDM_DRO@yahoogroups.com
[mailto:CAD_CAM_EDM_DRO@yahoogroups.com]On Behalf Of David Speck
Sent: Sunday, May 08, 2005 11:14 AM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: [CAD_CAM_EDM_DRO] 3 Phase rotary converters


Anyone have experience designing 3 phase rotary converters?

I'm building a 10 HP unit now, and have seen designs for self starting
systems that use a voltage sensitive (potential) relay connected between
the midpoint of the powered winding and the derived phase to disconnect
the start capacitors when the converter motor reaches full speed.

Can anyone suggest at what voltage the start relay should drop out?
I've seen specific part number suggested, but no actual voltage ratings.

Thanks in advance.
Dave


Addresses:
FAQ: http://www.ktmarketing.com/faq.html
FILES: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/
Post Messages: CAD_CAM_EDM_DRO@yahoogroups.com

Subscribe: CAD_CAM_EDM_DRO-subscribe@yahoogroups.com
Unsubscribe: CAD_CAM_EDM_DRO-unsubscribe@yahoogroups.com
List owner: CAD_CAM_EDM_DRO-owner@yahoogroups.com, wanliker@...,
timg@...
Moderator: pentam@... indigo_red@... davemucha@...
[Moderators]
URL to this group: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO

OFF Topic POSTS: General Machining
If you wish to post on unlimited OT subjects goto:
aol://5863:126/rec.crafts.metalworking or go thru Google.com to reach it if
you have trouble.
http://www.metalworking.com/news_servers.html

http://groups.yahoo.com/group/jobshophomeshop I consider this to be a
sister site to the CCED group, as many of the same members are there, for OT
subjects, that are not allowed on the CCED list.

NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING THEM.
DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........
bill
List Mom
List Owner


Yahoo! Groups Links