Stepped airgap choke ? - diyAudio
Go Back   Home > Forums > Amplifiers > Tubes / Valves

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

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 11th August 2008, 05:57 PM   #1
diyAudio Member
 
Join Date: Jul 2004
Location: Sweden
Default Stepped airgap choke ?

Hi
I took a close look at one of my scrapbox chokes and found that the airgap is sectioned in two steps (see pix).
What is the purpose of this ?
Is this a swinging choke, or .. ?
How does that influence the properties of the choke ?
Brgds
Pix
Attached Images
File Type: jpg dsc00007_ii.jpg (55.0 KB, 301 views)
__________________
Pix
  Reply With Quote
Old 11th August 2008, 07:26 PM   #2
diyAudio Member
 
Richard Ellis's Avatar
 
Join Date: Sep 2006
Location: Mar del Plata, a BIG seasonal getaway city, can see the Ocean from our residence.
Default Stepped gap?

I doubt it very seriously that this is a "stepped gap" TX rather it is probably a poorly 'reassembled' stack, notice the iregularly stacked laminations & the gap on the left inner stack in the middle.
This TX will perform poorly as it is not stacked 'right' it needs to be taken apart & realined correctly.....somebody did try to reassemble it & got it wrong.
It is very tricky to get it aligned right....& you'll probably find it will come apart easily as it seems it has been apart once already.
______________________________________Rick........ .
Interesting concept of a stepped gap however!
  Reply With Quote
Old 11th August 2008, 07:42 PM   #3
diyAudio Member
 
Join Date: Jul 2004
Location: Sweden
Richard,
Ok, I might take it apart and tap the laminations flat, and reassamble it.
I dont have the equipment to measure it with DC current (just a AC bridge)
So, I have to aim for the airgap which are at the sides of that middle "tapp".
I measured 25mH/0,3 Ohm, So I thought it could be a nice heater choke for 2-3 Amp.
Brgds
Pix
Sweden
__________________
Pix
  Reply With Quote
Old 11th August 2008, 10:01 PM   #4
diyAudio Member
 
Tom Bavis's Avatar
 
Join Date: Jun 2002
Location: Macedon NY
Looks to me like it was intended to have a dual gap. This will maintain some inductance to a higher current, giving regulation over a wider current range - essentially it's a swinging choke.
  Reply With Quote
Old 12th August 2008, 07:07 AM   #5
diyAudio Member
 
Richard Ellis's Avatar
 
Join Date: Sep 2006
Location: Mar del Plata, a BIG seasonal getaway city, can see the Ocean from our residence.
Default Laminations

It just seemed to me the stacks were kinda inconsistant, note the overlap on the lams.
So this is the design of the famous 'swinging' choke huh? Cool, now I know.....what to look for too!
_______________________________________Rick....... ...
Attached Images
File Type: jpg lam.jpg (11.2 KB, 155 views)
  Reply With Quote
Old 12th August 2008, 09:45 AM   #6
diyAudio Moderator Emeritus
 
ray_moth's Avatar
 
Join Date: Jan 2004
Location: Jakarta
Quote:
essentially it's a swinging choke
Is it? I thought a swinging choke was just a choke with a narrower than normal gap, so that its inductance would fall more quickly with increased current?
  Reply With Quote
Old 12th August 2008, 10:12 AM   #7
diyAudio Member
 
Join Date: Jul 2004
Location: Sweden
Default So perhapps I should left it as it is then

Well, The two step airgap distance is about the same at both airgaps (top and bottom), and also the varnish is intact, which speaks for that this type of airgap was intended from the manufacturing of the choke.
Of course, it could have been a badly assembled choke from the beginning, but sins the varnish is intact, at least it was not damaged by a drop or so by the user.
This choke was originally a part of a psu-box to a traffic-light from the 60-ties. Unfortunately I dont have the schematics left. But from what I remember there was a lot of high current inductors in this PSU-box. I think the purpose of this box was to regulate the voltage for the Lights.
Brgds
Pix
Sweden
__________________
Pix
  Reply With Quote
Old 13th August 2008, 02:09 AM   #8
diyAudio Member
 
Join Date: Jul 2003
Location: Ann Arbor, MI
Quote:
Originally posted by ray_moth

Is it? I thought a swinging choke was just a choke with a narrower than normal gap, so that its inductance would fall more quickly with increased current?
hey-Hey!!!,
I think the swingers saturated their cores gradually. That implies a varied gap, and enough turns to stand some AC. I don't think it would matter how the gap was different, just so as not to saturate it at a single DC current value.
cheers,
Douglas
__________________
the Tnuctipun will return
  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
Airgap for filament transformer ? Lauscher Tubes / Valves 11 29th April 2009 06:41 PM
Choke rating for choke input duty cbutterworth Tubes / Valves 14 9th November 2007 05:43 PM
Swinging Choke or Smoothing Choke danFrank Tubes / Valves 4 11th February 2007 12:05 PM
Stepped Gap Choke ChocoHolic Power Supplies 6 26th June 2005 11:30 AM
Airgap in transformers? Loial Power Supplies 7 23rd December 2004 11:13 AM


New To Site? Need Help?

All times are GMT. The time now is 02:09 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