[Boatanchors] Relay Repair - Demagnetization Question

[Carl]

While there was some variety in early frequencies, 115 became a defacto standard before WW2 in the universal replacement market.

The 38 Buick I worked on is synchronous and I took that apart to burnish for long term reliability. Most of my customers dont want modifications or SS replacements. Id have preferred changing to a 4 pin socket, an asynchronous vibrator and some SS diodes which is what Ive done to the Buicks in my collection. The signing vibrator is part of the enjoyment driving along....its what I grew up with.

Carl


  ----- Original Message ----- 
  From: WA5CAB at cs.com 
  To: km1h at jeremy.mv.com ; boatanchors at mailman.qth.net 
  Sent: Wednesday, February 03, 2010 11:23 AM
  Subject: Re: [Boatanchors] Relay Repair - Demagnetization Question


  If your method works well for you I wouldn't change it.  But the method I described also came from the vintage car people and has worked well for me.  In the self-rectifying circuits, the contacts in the secondary are switching anywhere up to about 550 volts, depending upon the supply.  

  You're right about the 115 cps.  I forgot about them last night.  In most of the 30's and 40's supplies I work on, 100 cps is common but most of the 50's vintage run at 115.  A few are faster.

  In a message dated 2/3/2010 8:38:05 AM Central Standard Time, km1h at jeremy.mv.com writes: 

    I just dont care for that much voltage to clean the contacts; the idea is to 
    use just enough to remove the oxide without leaving pitting. Its comparable 
    to using a burnishing tool versus a points file.

    There are a couple of methods used or championed by the vintage car people 
    and Ive been happy with the one I use for many decades.

    Most auto vibrators run at 115 cps and there is a fairly even distribution 
    between 6V and 12V radios arriving here. The big rush to 12V systems started 
    in 53.



  Robert & Susan Downs - Houston
  wa5cab dot com (Web Store)
  MVPA 9480