Reply
 
Thread Tools Search this Thread Display Modes
 
Old 05-12-2008, 06:27 PM   #1
1 Rivet Member
 
1971 25' Tradewind
Roanoke , Virginia
Join Date: Apr 2007
Posts: 5
Dead Univolt

Does anyone have a schematic for a Univolt Model 35, S/N 9425? The full wave rectifier that converts AC to DC has failed -- I would like to repair unit, and reuse it as a battery charger in my shop. I need the schematic to determine what the rectifier specifications are, what else may be wrong, and to help me understand how the circuit board controls the SCR. Or, if anyone has a good full wave rectifier (mine is epoxy encapsulated and is mounted on an aluminum plate for cooling) from a deceased Univolt, that would be a great help. The Univolt is out of my 1971 25' Land Yacht, and will be replaced with a converter having a smart battery charger in the near future.

Thanks,
Phil Weaver
__________________

__________________
Phil Weaver is offline   Reply With Quote
Old 05-12-2008, 06:34 PM   #2
Well Preserved

 
1993 21' Sovereign
Colfax , North Carolina
Join Date: Jun 2003
Posts: 20,190
Can you just use a diode trio from, say an old GM alternator?
__________________

__________________
Meddle not in the affairs of dragons, for you are crunchy, and taste good with ketchup.
Terry
overlander63 is offline   Reply With Quote
Old 05-12-2008, 06:39 PM   #3
Rivet Master
 
TomW's Avatar
 
1967 26' Overlander
Huntsville , Alabama
Join Date: Dec 2003
Posts: 2,918
Images: 2
Half-wave rectifyer

Quote:
Originally Posted by Phil Weaver
Does anyone have a schematic for a Univolt ...
The SCR's exact function in my unit puzzled everyone who saw the schematic.

Tom
TomW is offline   Reply With Quote
Old 05-12-2008, 07:39 PM   #4
Ham KI4HJX
 
1982 27' Excella
1970 23' Safari
Franklin , 28734
Join Date: Jul 2007
Posts: 126
Scr

The SCR must be to turn the voltage to the battery off when it reaches full charge. However I can't see how it would work the way it is drawn are you sure that D4 is not turned the other way? A SCR will conduct untill the polarity is reversed or you cut the power feed.
By the way my Univolt killed a brand new Optima gel battery, I think I would rather have a battery charger from Wally world. These old DC power supplies would work for a long time the new switching mode one's are easy to kill and hard to repair. The new battery chargers will not turn on unless they see that they are conected to a battery that has some voltage present.
__________________
Ramp is offline   Reply With Quote
Old 05-13-2008, 07:01 PM   #5
1 Rivet Member
 
1971 25' Tradewind
Roanoke , Virginia
Join Date: Apr 2007
Posts: 5
Terry, the alternator diodes are an excellent idea, and I may have to use them. However, if I can find an exact replacement part, I would not have to modify the Univolt to accept the new diodes -- life would be easier.

Thanks for your help.
Phil
__________________
Phil Weaver is offline   Reply With Quote
Old 05-13-2008, 07:28 PM   #6
1 Rivet Member
 
1971 25' Tradewind
Roanoke , Virginia
Join Date: Apr 2007
Posts: 5
Tom, my Univolt regulation circuit has three transistors, many diodes, small capacitors, resistors, and a trim pot. There seems to be some type of voltage sensing (a fine guage winding) connecting the transformer's primary and secondary windings. To me it's overly complicated, I would not have designed it like that. The SCR turn-on time is regulated by this circuit, and I would definately like to have a schematic and parts list.

I looked at your schematic, it has a much less complicated regulation circuit. I am not sure what the purpose of R2 and D3 are. I think it would work just as good without them.

Still looking for info!
Thanks,
Phil
__________________

__________________
Phil Weaver is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Dead battery msmst25 Electrical - Systems, Generators, Batteries & Solar 6 10-05-2007 06:03 AM
dead short? DUNSKI Batteries, Univolts, Converters & Inverters 1 07-03-2007 05:14 PM
Well, its DEAD! SilverToy Tow Vehicles 34 06-30-2007 01:56 AM
Dead ...really dead Melody Ranch Batteries, Univolts, Converters & Inverters 17 06-13-2007 01:23 AM
Dead bolt Scaler113 Doors & Locks 0 11-08-2004 09:20 PM


Virginia Campgrounds

Reviews provided by




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 01:30 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.

Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.