Help: conversion from 110v to 220v - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 30th November 2002, 12:38 AM   #1
diyAudio Member
 
Join Date: Jul 2002
Location: Texas
Default Help: conversion from 110v to 220v

Hi,

I need to convert an English ss amp "monogram reference 3100 class A+" back to 220v. I suppose it was factory rewired in US for using 110v mains supply.

In the interior of the amp, I found that the wire a, b and c from the power suupply sockets were connected to the power transformer as follows:-

wire a to wire w and x
wire b to wire y and z
wire c to wire c' (earth)

I believe that the transformer has a dual primary windings (it was designed to take 110 to 240v.

My questions are:
1/ could the conversion be done by shorting the wires x and y, or wires x and z?
2/ what would be the consequence of mis-connection?
3/ has anyone heard about this amp before?

Thank you in advance for your kind help.


Best wishes,
Russell SIT
  Reply With Quote
Old 30th November 2002, 01:06 AM   #2
diyAudio Member
 
Join Date: Feb 2002
Location: Western Sydney
Default Transformer wiring

IF it does have dual primary windings, (they should be in parallel for 110V), they should be wired in series & in phase for 220V.

BE CAREFUL....
  Reply With Quote
Old 30th November 2002, 03:05 AM   #3
diyAudio Member
 
Join Date: Jul 2002
Location: Texas
Default How to know they are in phase?

Thank you to your prompt reply.

How could I be certain that the 2 primary windings connected are in phase? What would happen if they are connected out of phase, e.g. blow the fuse, transformer or the whole amp, or just no output from the big iron?


Best wishes,
Russell SIT
  Reply With Quote
Old 30th November 2002, 03:18 AM   #4
diyAudio Member
 
Join Date: Feb 2002
Location: Western Sydney
Default phased out

Out of phase, you should get next to no output.

Probably best to disconnect the secondary from the amp circuitry before you start playing with this.

Pete McK
  Reply With Quote
Old 30th November 2002, 04:17 AM   #5
Variac is offline Variac  United States
diyAudio Editor
 
Variac's Avatar
 
Join Date: Dec 2001
Location: San Francisco, USA
They told me to use a fuse on the input too. If it is wrong the fuse will blow mighty fast avoiding a melt down Is this true that out of phase is possibly dangerous ?
  Reply With Quote
Old 30th November 2002, 04:39 AM   #6
paulb is offline paulb  Canada
diyAudio Member
 
Join Date: Jun 2001
Location: Calgary
See the first schematic (Type 7 primary) here:
http://www.plitron.com/pages/Products/Std/schemati.htm

If you wire them out of phase it won't blow the fuse, just give very little output, as Pete said. But always use a fuse.
  Reply With Quote
Old 30th November 2002, 04:56 AM   #7
diyAudio Member
 
Peter Daniel's Avatar
 
Join Date: Jul 2002
Location: Toronto, Canada
Send a message via AIM to Peter Daniel
I would try to connect:

wire a to wire w
wire x with wire y
wire b to wire z

providing that x-y is not the same winding (but rather w-y and x-z are the same). Before that, disconnect secondaries from the circuit and make sure the primary has a fuse..
__________________
www.audiosector.com
“Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC
  Reply With Quote
Old 30th November 2002, 04:25 PM   #8
djdan is offline djdan  Romania
diyAudio Member
 
Join Date: Dec 2001
Location: Romania
If you can , make some measurements.

1. Disconect all the primary and secondary wires.
2. Check the Inductance and Rezistance in primary.
3. Try to discover two windings with same characteristics.
4. Conect in series and measure the inductance.
- If the inductance is double it is OK
- If the inductance is half it is not OK becouse is out of phase.
5. Inject in the new primary a small tension ( 24 v AC ) from a small transformer and check the voltage in secondary.

If everything is OK you can try to 240V for a very short time.
  Reply With Quote
Old 30th November 2002, 05:05 PM   #9
diyAudio Member
 
Join Date: Jul 2001
Location: Orleans, France
djdan,

If the two windings are serial conected in phase, inductance will be 4 times higher, because of the mutual inductance.

If the two windings are serial connected out of phase, inductance will be very low (theoretically zero), because, again, of the mutual inductance. This misconnection used with 240 vac supply can destroy the transformer in few seconds.

A good idea is to try the transformer with 24 vac instead of 240 vac, and to measure the voltage across secondary winding, wich must be 1/10th of the normal working voltage if all is correct. No voltage, or very low, denotes out of phase primary connection.

Regards, Pierre Lacombe.
  Reply With Quote
Old 30th November 2002, 05:38 PM   #10
Variac is offline Variac  United States
diyAudio Editor
 
Variac's Avatar
 
Join Date: Dec 2001
Location: San Francisco, USA
Doh!! I could use a selection from my Variac collection to run lower voltage through it. This is kinda embarrassing.......
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

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
110v or 220v, how can you tell? fjmart134 Tubes / Valves 2 8th June 2009 10:18 PM
VELODYNE 110V to 220V iblieve Power Supplies 1 11th May 2009 07:25 PM
AR XA 220V to 110V dan duette Analogue Source 2 13th February 2009 01:08 PM
Krell KSA 80 110v - 220V conversion. Need help webercarbmann Solid State 4 4th March 2006 12:22 AM
How to convert 220V to 110V??? Real Prober Digital Source 4 5th November 2004 07:02 AM


New To Site? Need Help?

All times are GMT. The time now is 01:58 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2