Connected a transformer wrong, I think - diyAudio
Go Back   Home > Forums > Amplifiers > Power Supplies

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 26th April 2013, 07:50 PM   #1
diyAudio Member
 
Join Date: May 2012
Unhappy Connected a transformer wrong, I think

I purchased a transformer ( Myrra 45065 http://www.farnell.com/datasheets/484324.pdf ) and I clearly did something wrong as it overheated in only a few seconds - I disconnected it as quickly as I could.

Now, I do have electronics experience, but mainly signal electronics and mains repair work. I bought this transformer because I wanted a dual 18V AC supply to connect to an old Soundcraft Spirit folio 122 mixer to see if it is working.

I connected the mains via veroboard to transformer pins 1 and 9, and then linked 4 and 6. I didn't attach anything to the apparent secondary winding, I just soldered 16,17,14,12 to the veroboard as I wanted to check the output. I didn't link the secondary winding.

I'm totally confused, but this is the first time I've dealt with a transformer so I prob made a stupid mistake. Any help greatly appreciated, thanks.

EDIT: I connected 240V to the apparent primary as I said earlier, not 110V.

Last edited by lonetraider; 26th April 2013 at 07:53 PM.
  Reply With Quote
Old 26th April 2013, 08:00 PM   #2
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
Your wiring is correct for the primary.

I would advise you power up with a bulb tester (search the forum for that ) but its just a low wattage mains filament bulb in series with the live supply. It saves mishaps. Then confirm the transformer is working OK and the secondary voltages are correct (without them connected to anything).

That's your first step.
__________________
-------------------------------------------------------
Installing and using LTspice. From beginner to advanced.
  Reply With Quote
Old 26th April 2013, 08:08 PM   #3
diyAudio Member
 
Join Date: May 2012
Quote:
Originally Posted by Mooly View Post
Your wiring is correct for the primary.

I would advise you power up with a bulb tester (search the forum for that ) but its just a low wattage mains filament bulb in series with the live supply. It saves mishaps. Then confirm the transformer is working OK and the secondary voltages are correct (without them connected to anything).

That's your first step.
That's a relief, thanks for the help, I'll get to it.
  Reply With Quote
Old 26th April 2013, 08:14 PM   #4
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
I'm thinking rather hazily now... could the phase of one of the primaries been incorrect.

I just looked on a similar (similar as in package style) transformer I use and its wired as you stated. So could yours be different ? and one winding needs reversing. Use a bulb tester though as it will save any problems.

If the tranny heated up as quickly as you say then something was seriously amiss.
__________________
-------------------------------------------------------
Installing and using LTspice. From beginner to advanced.
  Reply With Quote
Old 26th April 2013, 08:43 PM   #5
diyAudio Member
 
Join Date: May 2012
Quote:
Originally Posted by Mooly View Post
I'm thinking rather hazily now... could the phase of one of the primaries been incorrect.

I just looked on a similar (similar as in package style) transformer I use and its wired as you stated. So could yours be different ? and one winding needs reversing. Use a bulb tester though as it will save any problems.

If the tranny heated up as quickly as you say then something was seriously amiss.
The bulb tester seems like a good idea, I put a 15 Watt bulb in series and it lit brightly so it does look like I've got a problem.

On the case, it says the following;

115V (1-4)
115V (9-6)

I'm thinking you're right, although I'm new to this it would make more sense if it were (this would tie in more with the way I originally wired it);

115V (1-4)
115V (6-9)

So, looking at this, should i link 4 and 9, and apply 240V to 1 and 6?
  Reply With Quote
Old 26th April 2013, 09:09 PM   #6
diyAudio Member
 
Join Date: May 2012
You were right Mooly, I connected like I said in the last post and got a two steady 18.3V out the secondaries, the 15 Watt bulb was also dim.

The secondaries are;

18V (12-14)
18V (19-17)

I'm going to connect the mixer to 12 and 17 while linking 14 and 19 to get my common ground.
  Reply With Quote
Old 26th April 2013, 09:54 PM   #7
diyAudio Member
 
Join Date: May 2012
It worked, so thanks a lot for your help Mooly!
  Reply With Quote
Old 27th April 2013, 08:32 AM   #8
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
Excellent, that's great to hear
__________________
-------------------------------------------------------
Installing and using LTspice. From beginner to advanced.
  Reply With Quote
Old 27th April 2013, 03:09 PM   #9
diyAudio Member
 
Join Date: Sep 2010
For confirmation and to ensure you get the secondaries correct.
From p.23 of Myrra's general catalog...

http://docs-europe.electrocomponents...6b80f3c2a1.pdf
Attached Images
File Type: png myrra.png (41.0 KB, 59 views)
  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
amplifier works connected to PC .. but not when connected to car radio anwaypasible Analog Line Level 1 2nd March 2011 08:42 PM
Wrong Voltage / current on BoZ... or Wrong Measuring ? gionag Pass Labs 8 14th May 2008 12:24 PM
dual secondary transformer connected in series Leolabs Solid State 2 7th October 2006 12:38 AM
Mains filter wrong connected in an industrial product! Franz G Digital Source 2 29th January 2006 11:27 PM
shorted mains with transformer connected jarthel Parts 7 8th March 2004 05:48 PM


New To Site? Need Help?

All times are GMT. The time now is 04:44 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