Mailing List lml@lancaironline.net Message #64605
From: Jack Morgan <jmorgan1023@comcast.net>
Sender: <marv@lancaironline.net>
Subject: Strobe draw.
Date: Mon, 18 Feb 2013 08:12:30 -0500
To: <lml@lancaironline.net>
Hi Charlie,

The strobe power supply does draw power cyclically in sync with the strobe flashes. The inverter runs continuously drawing low power after charging the strobe energy capacitors and higher power during the recharge interval. This is a relatively small fluctuation and is partially filtered by the strobe power supply to insure it doesn't radiate and upset radio reception. It does show up as current fluctuation in my G900 but will not damage an alternator regulator. The autopilot has a similar current fluctuation depending on how much the servos need to work in rougher air. Same filtering needed in the autopilot controller and again not big enough to damage anything in the charging system.

Current fluctuations of any magnitude should not damage the charging system.... think hydraulic pump or A/C compressor cycling. I would look at the back up alternator's controller to isolate why it is kicking in.

Hope this helps.

Jack Morgan

On Feb 18, 2013, at 6:03 AM, Lancair Mailing List wrote:

From: Charles Brown <browncc1@verizon.net>
Subject: strobe light power draw
Date: February 17, 2013 2:16:22 PM EST


Amigos, 

My 24V strobe light systems draws 3-4 amps like Whelen says it should, but seems to do it cyclically, i.e., a 0-4 amp sine wave with period equal to the flash rate (about 3 sec).  Can anyone tell me if that is normal, or should it be a steady 3-4 amp draw?  (12V guys, same question only 12V Whelen strobes should pull around 7 amps)

< I ask because it's making prime alternator amps cycle up and down; bus voltage cycle up and down, only about 0.1V; but it may be related to the demise of two successive regulators for the backup alternator, which starts kicking in at 3-sec intervals, with loud "BONG" alerts from the Garmin.  You are invited to enjoy the mental spectacle of the Garmin BONGING me into insanity while I hurl epithets at the instrument panel as I alternately shut off ALT 1, then ALT 2, then both, trying to figure this out when I SHOULD be sitting back, smoking a stogie, and watching the Texas hill country scenery slide by. PS -- Alternator one regulator checks out good with good ground and power paths etc >

Charley

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