Mailing List flyrotary@lancaironline.net Message #15904
From: Ed Anderson <eanderson@carolina.rr.com>
Subject: Re: [FlyRotary] Re: Battery load test
Date: Mon, 24 Jan 2005 12:17:46 -0500
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
 
----- Original Message -----
Sent: Monday, January 24, 2005 9:47 AM
Subject: [FlyRotary] Re: Battery load test

Wendell,

There is some benefit to using a starter relay in addition to the starter solenoid.  The argument is that this arrangement will keep the fat wire going to the starter from being always hot.  Also, I’ve heard stories of starter solenoids sticking with no way to stop the starter until it runs the battery dead.  Not sure I buy that argument though.  I tied my alternator B+ wire to the battery terminal on the solenoid (mounted on firewall) rather than running it all the way back to the battery (in the tail).  I also picked up on the same B+ terminal to provide power to the Main Power Buss.  This saved about 25’ of heavy gauge wire, offsetting the weight of the solenoid.

 

Mark S.

    

 

 

Refering to the battery going directly to the starter,  most all starters with built in solinoids are so wired.  I remember having a starter to hang on occasion and drain the battery or ruin the starter.  Is it practicle to use a relay in conjunction with the starter/solenoid set up?

Wendell

 

Wendell, I would say that is still a standard for aircraft - for some on the reasons already mentioned.  With a relay(Contactor) you can break the circuit to the starter should it stick or short.  I also have a LED above my starter switch that is on so long as there is juice to the starter - that way you can tell if the starter is still engaged after the engine start - happens occasionally and ruins starts and sometimes the gear teeth on the starter ring.

 

However, there are folks who are now doing away with the contactor feeling it is heavy and there is low risk of a hang-up happening.

 

Ed A

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