In a message dated 98-06-04 09:02:07 EDT, bschwart@pacbell.net writes:
> You would certainly lengthen the life (at least of the switch and the relay
> and possibly the solenoid) by at least double by halving the amount of
> actuation/de-actuation cycles! Although there's not really anything to
> wear out in a solenoid I have herd stories of them failing and this may be
> due in part to cycling fatigue of the connections to the wire of the coil
> inside the solenoid itself. This and the heat of the unit while in
> operation, so reducing the cycling times surely can't hurt!
Barry,
There are actually two coils in the OD solenoid -- One heavy duty coil to pull
the solenoid in place, and another lighter duty coil to hold it in place after
it has been pulled into place. The heavy duty coil draws a LOT of current.
Once the solenoid has actuated, it operates a switch which disconnects the
heavy duty coil, leaving only the low current drain holding coil energized.
This switch is a common failure point. Anytime you switch an inductive load
(coil), the switch contacts take a beating. A diode would probably help, but
it would have to be a humongous diode for this application. I don't have hard
data, but I have been led to believe that the larger coil draws as much as
thirty amps!
You're right, the fewer times you operate this switch, the better (as well as
the manual actuating switch).
Dan Masters,
Alcoa, TN
'71 TR6---------3000mile/year driver, fully restored
'71 TR6---------undergoing full restoration and Ford 5.0 V8 insertion - see:
http://www.sky.net/~boballen/mg/Masters/
'74 MGBGT---3000mile/year driver, original condition - slated for a V8 soon
'68 MGBGT---organ donor for the '74
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