Go Back   Home > Forums > Commercial Sector > The diyAudio Store

The diyAudio Store A forum for discussing anything about the products available in The diyAudio Store.

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 29th May 2013, 04:36 AM   #91
Johno is offline Johno  Australia
diyAudio Member
 
Johno's Avatar
 
Join Date: Oct 2010
Location: Up in the alps - motorcycle heaven
Quote:
Originally Posted by AndrewT View Post
and two 12V relays will operate from the same 24V circuit supplied by DIYaudio

Tony sees my posts as unhelpful.Why?
because each transformer sees it's own current limiter. and each is unaffected by what the other transformer is doing/loaded.
I am just reading this thread and sorry to go back to old posts but there is some unsafe mains advice being offered that worries me.

All (reputable) transformer manufacturers that I know specify primary side fusing requirements based on allowable temperature rise. The recommended fuse is usually a slow blow rated at 150% of the VA rating of the transformer.

All the national wiring rules that I am aware of require that each mains connected transformer has its own over-current protection to mitigate fire risks, for most of us that means a fuse. In the worst case scenario you may find your insurance company voids your cover if they investigate your claim and find non-compliance.

Therefore, and to reinforce Andrew's recommendation, mains connected transformer primaries cannot be paralleled legally or with reasonable safety.

And this of course leads to the need for 2 soft start circuits wired after the fuses.
If like me you choose to use a small transformer for the control circuitry there will be a third mains fuse.
  Reply With Quote
Old 29th May 2013, 09:42 AM   #92
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
You can use one soft start circuit that has two outputs (from the one set on relay contacts)
BUT !!!!!!
each output needs a fuse for the transformer that output is feeding. i.e. fuse each transformer separately. This is very important !!!!!
__________________
regards Andrew T.
  Reply With Quote
Old 29th May 2013, 09:53 AM   #93
AJT is offline AJT  Philippines
diyAudio Moderator
 
AJT's Avatar
 
Join Date: May 2003
Location: Palatiw, Pasig City
I have seen a lot of Japanese amplifiers (circa 80"s) that had two big traffos, only one fuse, a single switch and no soft start circuit at all....

soft start circuit is indicated where there is a possibility that your power switch can get welded during turn-on.....where no such possibility exist, then there is no need for it at all...
  Reply With Quote
Old 29th May 2013, 03:02 PM   #94
SRMcGee is offline SRMcGee  United States
diyAudio Member
 
SRMcGee's Avatar
 
Join Date: May 2004
Location: Wynnewood, PA
Folks:

If the soft start board is ever updated, would it be possible to add the capability to supply the power needed to drive the speaker protection board?

Regards,
Scott
__________________
Good decisions are derived from experience; experience is derived from bad decisions.
  Reply With Quote
Old 14th June 2013, 07:54 PM   #95
diyAudio Member
 
Join Date: Sep 2009
Quote:
Originally Posted by SRMcGee View Post
Folks:

If the soft start board is ever updated, would it be possible to add the capability to supply the power needed to drive the speaker protection board?

Regards,
Scott
Good point!

It's very nice that one doesn't need an extra secondary (or even extra transformer) for the softstart - but what is it good for if you still need one for the dc protection ?

Honestly I'd even prefer some small block-transformer as seen on the Vellemann K4700 directly on the dc-protection PCB.
  Reply With Quote
Old 14th June 2013, 08:50 PM   #96
diyAudio Member
 
Project16's Avatar
 
Join Date: Nov 2012
Quote:
Originally Posted by AndrewT View Post
You can use one soft start circuit that has two outputs (from the one set on relay contacts)
BUT !!!!!!
each output needs a fuse for the transformer that output is feeding. i.e. fuse each transformer separately. This is very important !!!!!
It is not forbidden to talk about what kind of system directly connected to the mains on the forum?
Yet this is the same schematic as on this thread!
Softstart delay
  Reply With Quote
Old 24th June 2013, 01:18 PM   #97
diyAudio Member
 
Join Date: Sep 2009
Quote:
Originally Posted by Project16 View Post
It is not forbidden to talk about what kind of system directly connected to the mains on the forum?
Yet this is the same schematic as on this thread!
Softstart delay
Quod licet iovi non licet bovi!

Jason explains why this is the way it is, i.e. liability/insurance reasons.

For us non-US citizens this might seem strange though - but then we don't have the same laws!
  Reply With Quote
Old 3rd July 2013, 07:50 PM   #98
diyAudio Member
 
Join Date: May 2009
Location: São Paulo, Brasil
Hi, I'd like to know what happens if i use the exactly schematic in the first post with 110v. If a read correctly, it is for 230v...
  Reply With Quote
Old 16th November 2013, 07:30 PM   #99
Mallard is offline Mallard  Germany
diyAudio Member
 
Join Date: Jan 2003
Location: Germany, Luenen
Default Just coming to the thread

Hi,

I'm just about to start a serious F5T v.2 project.
I will use a dual mono setup: 2 x 800VA (24V) transformer feeding ~350kuF.

Actually I planned to use a CL30 in the mains as inrush limiter (like Nelson has recommended it in his F5T article). Now I'm a little uncertain if I should better use a soft start module...

And, I'm sorry for that, can someone please explain what the cap (C9?) in parralel to the mains is supposed for?

Thanks and Regards,
Kai
  Reply With Quote
Old 16th November 2013, 10:21 PM   #100
diyAudio Moderator
 
JojoD818's Avatar
 
Join Date: Mar 2003
Location: searching...
Are you referring to C9 on the Soft Start Board or the F5T?
  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
Soft Start PC Board organics1 The diyAudio Store 2 29th March 2013 04:18 AM
soft start power supply for dynaco st-70 yero Tubes / Valves 9 8th July 2011 08:43 PM
Adcom 565 DED!!! Soft Start Board? dracoskeeper Solid State 2 6th June 2010 04:29 PM
Blown 20watt 4.7uf on soft start board ben62670 Solid State 4 26th June 2007 05:29 AM
Commercial Soft Start board wytco0 Parts 0 5th August 2005 04:26 PM


New To Site? Need Help?

All times are GMT. The time now is 06:17 AM.


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