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Starter solenoid question

trib

Well Known Member
On the starter solenoid, there are two switch terminals, one labeled "S" and the other labeled "I". This is the part from Van's. I'm assuming the "S" is for the starter switch. What is the purpose of the "I" terminal? Something to do with an ignition?
 
Starter Contactor

This image is from the B&C website. The wiring for the Vans contactor would be the same:

my.php
 
You can connect this terminal to the small terminal on the starter.... I believe Van's instructions have you do that for PM starters...
 
Thanks Radomir and Rick. A picture IS worth a thousand words! By the way Radomir, from your earlier question, I threw away that rubber cover on the tach drive after using it as a paint mask when painting. I haven't gotten the cover yet but plan on getting one. Thanks for looking out for me!
 
Yep you are right, "I" = ignore

On the starter solenoid, there are two switch terminals, one labeled "S" and the other labeled "I". This is the part from Van's. I'm assuming the "S" is for the starter switch. What is the purpose of the "I" terminal? Something to do with an ignition?
Yep "S" (for starter) gets momentary switched 12 volt power. A good approx wire size is about 18 awg and is fused with a 7 amp CB or fuse.

"I" is ignition and has to do with cars and coil point ignitions (** if you want to know why).

"I" terminal is powered with 12 volts when the normally open contactor closes. When you release the starter button the contactor opens and power is removed from the starter and the "I" terminal.

You could connect "I" to a panel start light if you wanted to, but 99.99% ignore it. I'd cut it off the threaded stud and save 2 grams. :rolleyes: (*** Don't get confused, this is NOT a run-on starter light.)

Make it look like this:
relaydiodes2mm8.jpg



** What is "I" really for? Typical point-coil ignitions have a big resistor to lower the voltage to the coil, prolong point life. However during start, full avaiable electrical power goes through the "I" terminal to the coil. This assists starting, bypassing the resistor. Since voltage is down already due to the draw of the starter during cranking, the resistor is not desirable during start. Pretty common stuff in 1960's and 70's cars. Often this wire gets disconnected or broken and cars whould be hard to start. Common fix or check is check coil voltage during cranking. Often the engine would "catch" just as you let go of the starter. I had some old Chevy's.

*** Starter Run ON: Having a firewall contactor (solenoid) eliminates this worry or at least minimize it in theory. The worry is if the starter remains engaged to the flywheel the starter acts as a generator, causing electrical havoc. If you want a run on light, put it on the starter, not the firewall contactor. Not many put a run on light in their RV. Skytec has a run on light KIT. It's just 20 bucks in wire, fuse holder, fuse, a few wire terminals, lamp and lamp holder. The firewall contactor should provide protection from run-on, but skytec claims that poor quality firewall contactors (made by White Rogers) or improper type contactors (continuous duty used, should be intermittent duty) where used on Pipers and Cessna's, which caused run-on problems. Here is their explanation. It's not an issue with the contactor Van's sells (Intermittent duty made by colehersee). It's the right one. Run-on caused by our firewall contactor is a nil concern in my opinion. I don't see how our firewall contactor could fail or weld closed. Remove power from the coil, it opens. Most of the STUCK starter run-on stuff involve the solenoid ON the starter, so put the run-on light there, if you desire. Personally I did not bother. (Diagram)
RunOnLightDiagram.jpg
 
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Who makes Vans Starter Solenoid?

Does anybody have a reference for the manufacturer of Vans Starter Solenoid? (aka Starter Contactor)

The Battery Solenoid is made by Cole Hersee, part number 24115. BTW it is a continuous duty part, rated to make or break 85A. In a related question, does anybody know what the typical and max coil current is for the Battery Solenoid?

I think the Starter Solenoid may be like a Cole Hersee 24021, since it seems to have a coil that ties to the ground on the bracket and it has the "I" terminal which they call a "resistor shorting circuit". That part is rated to make 750A, and break 100A. Does anyone know what the typical and max coil currents are for this one?

The Starter Solenoid I got from Vans is marked with 12V, 5573, 8CA, and Made in USA. The two smaller terminals are marked "I" and "S" but there are no other markings.

Thanks for any info,

dave
 
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Thanks D. I had seen that thread and it has some good info. What I'm looking for is the manufacturer / part number / datasheet on the Vans starter solenoid. I'm trying to have that data on every component in my airplane.

I plan to measure the solenoid current... I'm sure it will be near the 3.5A reported in the thread above.

Thanks again,
 
Would like the same info.

My search for the same info led me to this thread. If anyone knows what the Cole-Hersee PN is and where to find a spec sheet, I'd love to have the info.
 
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