Starter Cranking Problems for NH L220

[melben]

OK guys, I did a amp test on my Nippon starter with a non calibrated dash style gage and the solenoid drew about in the 10 amp range while cranking, I then took a Blue Point ohm meter and tested the solenoid coil ohms, 1.0 ohms, so applying ohms law to those figures the amps draw of the solenoid would be exactly what the system voltage is at the time of crank. So if the battery float voltage is 12.6 after sitting that is where the amps needed should be to hold adequate voltage at the tab, the cranking voltage will of course drop but there will need to be enough volts-amps to engage and keep the solenoid engaged.

That is not to say that it will not engage at less than that but that is the actual figures involved with that circuit by applying ohms law.

For the fact I was using a 0-30-60 amp gage I think the needle position was reasonably close to 10V cranking.

Just throwing this out for you guys to ruminate on, LOL.

Wuddya think guys.

Mel

 

[Delmer]

You've convinced me.

Grease monkeys doing using math formulas is about as dangerous as engineers trying to use common sense, but here goes. If a coil has "straight" resistance and it draws 10 amps at 12V then it will draw 8.3A at 10V and 6.6V at 8V which equals 53 watts, instead of 120 watts at 12V. Now a battery should easily produce 10 amps at 12V, but if the wiring is marginal like you suggest, then the solenoid gets a lower voltage, draws lower amps, lower watts and not enough to "pull" it in.

Relatively easy solution though.

 

[melben]

Delmer,

I am retired after 50 + years working on this stuff which qualifies me as a grease monkey for sure and had my share of hydraulic oil baths and have created quite a few Exxon Valdez size oil spills. Electric stuff was kinda my specialty in the shop. I do not know if I am on the right track with Stumpy but looking at it from my perspective and experience only. I would be able to go to McDonalds if I had a dollar for every relay kit I put on Nippon starters on Case 1840--45 --580 E's etc

I am also a advanced license holder (KC3EH) in Amateur radio which means I had to test in electric and radio theory to get through the various class levels and learn that dreaded Morse code to advance and that makes you just smart enough to know that electrical components work by means of smoke circulating inside them, proof being that when the smoke leaks out the component usually quits working.

I am sure with the combined wisdom of all on board here we can at least point Stumpy in the right direction. Lots of wisdom from some people who's knowledge is obvious from their in depth posts.

Looking ahead a few weeks I would like to take this opportunity to wish all my forum friends a Merry Christmas and Happy New Year.

Sincerely Mel.