Sender: <marv@lancaironline.net> (Marvin Kaye)
To: flyrotary
Date: Wed, 05 Mar 2003 20:33:39 -0500
Message-ID: <redirect-2044865@logan.com>
From: Charlie & Tupper England <cengland@netdoor.com>
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Subject: Re: [FlyRotary] Re: Starter solenoid
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Peter Cowan wrote:

> Re contactors and solonoids (maybe it would be clearer to talk about 
> only contactors or only solonoids - aren't they the same?)
>
>     Maybe I'm confused but on my Lycoming, the only solonoid for the
>     starter is the separate contactor near the battery (in addition to
>     the master switch contactor). This is different from auto starters
>     where there is a contactor/solonoid right at the starter.
>     On my mazda installation the builder had a hot line from the
>     battery to the starter solonoid. I changed it to route from the
>     master contactor so that it is still hot when the master is on but
>     dead when master off.
>     Is someone suggesting  2nd contactor for the starter?
>     Peter
>

Unsophisticated explanation:

The terms get used interchangably (is that a word?) but technically, a 
contactor is a 'heavy duty' relay. A solenoid is a device that uses 
electrical energy to cause a physical movement. Usually linear, but can 
be a rotary motion. A typical automotive starter 'solenoid' serves both 
purposes by switching the high current voltage to the motor and in the 
same motion moving the pinion gear to engage the flywheel gear. Old 
style Lyc starters get their gear movement  from the 'bendix'  & the 
'solenoid' for it is just a contactor.  That's why the starter pinion 
doesn't retract when a Lyc fails to start.

Does this help?

Charlie