Film-Tech Forum ARCHIVE: Stablization Magnets

This is topic Stablization Magnets in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

To visit this topic, use this URL:
https://ft-forum.com/ft/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=010357

Posted by Jeremy Weigel (Member # 4208) on 03-01-2010, 08:02 PM:

I have a Strong Super Highlight(circa 1988) at a 5.5 degree down angle that I just changed the bulb(Christe CXL-20R) in and can not get the arc to fully center. The previous bulb experienced the same problem. The magnet has been adjusted up as close to the bulb as the bracket allows. So my question is: Do these magnets loose strength over time?

Posted by Gordon McLeod (Member # 33) on 03-01-2010, 08:12 PM:

Heat definetly weakens a magnet over time
Also check that it is in the correct polarity

Posted by Jeremy Weigel (Member # 4208) on 03-01-2010, 09:41 PM:

Polarity checks out. I'll see if Strong still has these available.

Posted by Donald Brown (Member # 5427) on 03-02-2010, 01:14 PM:

Magnets in any lamphouse will loose their strength over time. It would be a good idea to check the alignment of the bulb in relation to the magnet again. While you may have adjusted the position of the magnet to "follow" the bulb, the field alignment may no longer be the same as intended, particularly if you have adjusted the travel of the bulb or changed the bulb from original spec's.
Even magnets in the old arc-lamps needed replacement or recharge after long service or modification of use, for example upgrading to larger carbon size.
Strong has replacement magnets available, or your unit could be sent out to a company such as Eriez Magnetics (I hope that I spelled that correctly) for recharge. You could also pick up a used magnet, salvaged from a similar lamp house, and send it out, if down time is a consideration.
Don Brown

Posted by Mark Gulbrandsen (Member # 72) on 03-02-2010, 05:57 PM:

I have had to replace the magnets on a number of Super Lum-Ex's because the magnets had become weak. When combined with a switcher power supply and a lamp house with weak magnets the arc would take a horse shoe shape at ignition and some tmes the arc would never settle down. New magnets solved the problem...

Mark