Limiting Inrush?? - 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 30th March 2006, 03:34 PM   #1
Deltat is offline Deltat  United States
diyAudio Member
 
Join Date: Oct 2004
Location: St. Louis, MO
Send a message via AIM to Deltat Send a message via MSN to Deltat Send a message via Yahoo to Deltat
Default Limiting Inrush??

Will the following circuit work to limit the inrush current from my 625VA transformer?

Kurt
Attached Images
File Type: jpg soft start.jpg (18.6 KB, 364 views)
  Reply With Quote
Old 30th March 2006, 03:50 PM   #2
diyAudio Member
 
ifrythings's Avatar
 
Join Date: Oct 2005
The circuit will help with the inrush of current but why not just use a NTC?
  Reply With Quote
Old 30th March 2006, 04:07 PM   #3
edl is offline edl  Hungary
diyAudio Member
 
edl's Avatar
 
Join Date: Oct 2004
Quote:
Originally posted by ifrythings
The circuit will help with the inrush of current but why not just use a NTC?
Because it haven't got time to getting colder when you reswitch the amp fast (or in case of a short blackout), and the toroidal transformer will kick the fuse because of the inrush current. Some manufacturers using NTC for this purpouse, but it's a slightly incorrect solution.

Best regards,
  Reply With Quote
Old 30th March 2006, 05:30 PM   #4
Deltat is offline Deltat  United States
diyAudio Member
 
Join Date: Oct 2004
Location: St. Louis, MO
Send a message via AIM to Deltat Send a message via MSN to Deltat Send a message via Yahoo to Deltat
i really wanted to go with an NTC but im also affraid that since this is going to power a switching amp that it may not ever really get hot and lower its resistance.
  Reply With Quote
Old 30th March 2006, 06:12 PM   #5
Did it Himself
diyAudio Member
 
richie00boy's Avatar
 
Join Date: Nov 2003
Location: Gloucestershire, England, UK
Yes both good points. NTC are no good IMO. Your circuit is good, I would use a bigger amount of reistance though. Try it and see, it's easy enough to change the resistor.
__________________
www.readresearch.co.uk my website for UK diy audio people - designs, PCBs, kits and more.
  Reply With Quote
Old 31st March 2006, 09:53 AM   #6
edl is offline edl  Hungary
diyAudio Member
 
edl's Avatar
 
Join Date: Oct 2004
Here the AC-mains is 230V, and I'm using 47ohm/20-25W wirewound resistor. Anyway many amplifier-factory using this value.
On the margin: yes, your circut will work, as Richie said.
  Reply With Quote
Old 31st March 2006, 11:57 AM   #7
Deltat is offline Deltat  United States
diyAudio Member
 
Join Date: Oct 2004
Location: St. Louis, MO
Send a message via AIM to Deltat Send a message via MSN to Deltat Send a message via Yahoo to Deltat
I haven no delay circuitry, will what ever delay there is on the AC/DC conterter board be enough?
  Reply With Quote
Old 31st March 2006, 12:09 PM   #8
Electrons are yellow and more is better!
diyAudio Member
 
peranders's Avatar
 
Join Date: Apr 2002
Location: Göteborg, Sweden
Blog Entries: 4
By this you mean

If you don't have any problems with the inrush current, then you don't have a problem.
__________________
/Per-Anders (my first name) or P-A as my friends call me
Tube Buffered Gainclone in work |Thread || Diamond buffer |Thread for the group buy | Wiki
  Reply With Quote
Old 31st March 2006, 01:18 PM   #9
AndrewT is online now AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Hi,
try using a much smaller fuse once you have it up and running.
Aim for T6A or T8A. It might work with T5A if you up the resistor to 15r or 22r.

You want that mains fuse as small as possible to provide effective protection.
__________________
regards Andrew T.
  Reply With Quote
Old 31st March 2006, 01:33 PM   #10
testlab is offline testlab  United States
diyAudio Member
 
testlab's Avatar
 
Join Date: Dec 2005
Location: Grand Rapids MI
Check this out http://www.edn.com/article/CA198898.html
__________________
It's not whether you win or lose, it's how you lay the blame.
  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
Inrush current limiting heater filaments boywonder Tubes / Valves 14 2nd February 2009 07:33 AM
Inrush current limiting necessary for EI transformers Bama Slamma Power Supplies 10 6th November 2006 05:08 PM
Inrush Current Limiting Circuit haldor Parts 22 8th October 2004 03:06 PM
V/I Limiting richie00boy Solid State 17 29th August 2004 03:25 AM
limiting the HF in GC GregGC Chip Amps 0 6th January 2004 09:18 PM


New To Site? Need Help?

All times are GMT. The time now is 08:11 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