[Milsurplus] Hot PE-73 relay redux

[J. Forster]

You could probably replace the original winding with an equal number of
turns of #22 or #24.

-John

=================


> Jim,
>
> #20 is not a suitable replacement for 2 x #26.  2 x #26 is the same cross
> section as #23.  #20 is the same cross section (and resistance per foot)
> as 2
> x #23, or therefore 4 x #26.  So if you could wind the same number of
> turns
> of #20 on the coil, it would have a little more than half the resistance
> of
> the original coil (the mean turn diameter will be greater).  And draw
> nearly twice the current.  Since you probably can't get the same number of
> turns
> on (since it would result in a coil roughly twice the diameter of the
> original - fewer turns per layer and more layers), the coil current will
> at a
> rough guess be closer to 3x and it will get close to 3 times as hot.
>
> Also, not to pick a nit or anything, but solenoids are not relays.  Or not
> primarily.  A solenoid produces a mechanical movement from an electric
> current.  Relays mechanically close and/or open an electric circuit when
> energized with an electric current.  Some solenoids do also function
> secondarily as
> relays.  But not in golf carts.  Internal combustion engines often have an
> electrc starting motor with a small gear that engages a larger gear on the
> engine.  There are two common methods to engage the small gear with the
> large
> one - centrifugal and solenoid.  Centrifugal engagement mechanisms are
> commonly called by mechanics "the Bendix".  After the company that built
> the
> first commercially successful ones I think.  Starter motors equipped with
> a
> Bendix are controlled by a relay, not a solenoid.  Direct engagement
> starters
> are usually controlled by a solenoid, whose secondary function is as a
> relay.
>
>
> Or to cut to the chase, golf carts do not have starter solenoids, and
> neither do dynamotors.  They have relays.
>
> In a message dated 08/15/2011 23:47:16 PM Central Daylight Time,
> mcenfalz at humboldt1.com writes:
>
>
>> At Dennis W7QHO's recommendation, I dropped a golf cart starting
>> solenoid
>> in there and it works well enough to get me on the air. Runs cool, but
>> doesn't match the mounting. Good band-aid, though.
>>
>> I opened up the coil and it's a masterpiece of simplicity - big 1/2 inch
>> square copper contacts driven by a fat scramble-wound coil wound on a
>> bobbin. Looks to be ~#26 wire; 2 wires wound parallel and parts of it
>> were pretty
>> crispy. The progressive short theory looks to have been correct. Should
>> be
>> a simple fix once I get the new wire. I have a new 15# roll of #20 that
>> I
>> may try just because it's handy.
>>
>> Cheers!
>>
>> Jim Falls
>> K6FWT
>> Eureka, CA
>
> Robert & Susan Downs - Houston
> wa5cab dot com (Web Store)
> MVPA 9480
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