From: <rogersda@cox.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] starters and solonoids (pt. 2) again
Date: Thu, 7 Aug 2003 16:59:21 -0400
MIME-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
Message-Id: <20030807205929.LXTO28445.fed1mtao06.cox.net@smtp.west.cox.net>

Peter,

   I'm speaking in general here.  I don't have intimate knowledge of the specific Mazda electricals you might be using.

   Proper engagement of the starter motor depends on a couple of things happening in proper sequence.

  [1] power reaching the "low speed" windings of the motor.
  [2] as the motor begins to turn, the solenoid pushes the drive gear into engagement with the flywheel ring.
  [3] the solenoid closes its integral contactor, sending current to the "high speed" windings of the motor.

   The configuration you describe would be seem to be putting power directly to the high-speed winding, not giving the solenoid time to mesh the drive gear as it normally would during the brief low-speed phase.  That will result not only in missed starts, but rapid wear of the the drive and ring teeth.

Dale

 
> Looking at Dale's excellent freehand drawing with the change that the Motor
> M is wired directly to "C" (I'm not using the contactor just the solonoid),
> I thought of another potential issue. I'm now getting frequent missed gear
> engagements when I hit the starter switch. Could this be due to a slight
> "timing" difference between this setup and one solonoid/contactor? With the
> one Mazda solonoid/contactor the first thing that moves is the solonoid
> which throws the starter gear into the ring gear, then the electrical
> contact is made for power to the motor. So the gear is activated a little
> ahead of the contactor. With my setup, power gets to the motor at the same
> time as power to the solonoid windings so the motor is likely staarting
> before the gear engages. Any thoughts/
> Peter