MTFCA Forum

I was able to buy two Wilson hand cranked coil testers a few months ago and have them just about restored. Bob Cascisa has rebuilt and recalibrated the Jewell meters and I am anxious to receive them - promised delivery Monday by USPS. One is now complete but the other has a broken crank handle which I have not been able to replace. I have a reprinted Wilson catalog that shows the testers with the crank and with a vintage 1/4 hp electric motor. With the correct motor I will have the set so am going that direction. Do any of you know what make and model of motors might be right to use? Pics to follow.

I have an original KRW electric motor driven coil tester - photo is in Bob's great book ! It has a G.E. motor - I'll get back to you on the particulars.

Steve, Thanks for the reply. I was pleasantly surprised that the pic you posted was painted red. Both of mine appeared to be red originally so that is what I repainted them even though some forum posts suggested otherwise. I need to get Bob’s book, what a gentleman to work with!

 
KRW used a G.E. of Schenectady, NY, electric motor to drive the flywheel. It is ¼ HP, 1725 RPM.
 

 

Thanks Bob, now to find one.

Here’s another curiosity. When I crank slowly,clockwise, just fast enough to get a known good coil to fire it will cause a spark only on every other index mark. Rotating the direction of rotation causes the sparks to occur on the marks in between. Speeding up the rpm’s causes 16 sparks in either direction. Am I as crazy as my wife thinks I am?

What puzzles me is the “predictable” nature of this odd behavior,

Here's mine, works as advertised.

Every meter I've seen has been black.

Just for fun, last set of coils I did, spun mine the other direction. Seemed to work just the same. Being it is AC, don't know that it would matter which way you turn it, but clockwise in more natural for most people.

I don’t know how to explain what I saw. If I numbered the index marks 1 thru 16 and “slowly” cranked the tester clockwise the sparks occurred on the even numbers but when the rotation was reversed they occurred on the odd numbers. Speeding up the rotation caused sparks at each mark. Doesn’t really matter because you would never operate it that way but I’m curious about why it happens. If you have one give it a try - then tell me Whether I’m wacky or not.

Bob, Just tried six coils and got the same result. I would guess it happens at about 50 rpm. Speeding up just a bit they fire on all sixteen marks. I get your meters on tomorrow I’ll report on current.

David

Hand cranked testers do an interesting thing...at about 60RPM they are putting out around 4V, but are testing the coil very fast, as though the car was running around 2000RPM. In both instances, they are firing at their set amperage, but there is rise time to consider and the higher the voltage, the shorter the rise time. You may be experiencing a case where the coil is not receiving the necessary voltage to fire at the condition it's placed (very high simulated engine RPM). I think everyone who has one of these devices has experienced what you're experiencing and it is perfectly normal. When I was repairing coils and using a HCCT and a Strobospark, when on the HCCT, I would say that I cranked it at least 90RPM. Since Steve has a motorized HCCT, perhaps he will chime in with his estimated/calculated speed at which his machine runs.

Due to the low voltage at normal cranking speed, and testing at a very high period (1 coil firing at every magnet/pole passing), a coil set to fire correctly on the device was expected to run very well in a car. In a car, with 4 coils, each coil has ample time to rest, ramp, and discharge...not so on a HCCT, thus the HCCT was a very robust test at the time it was in common use.

Scott, That all begins to make sense except for the fact that the spark happens consistently at alternating positions depending on direction of rotation. I know it’s a “drive on a parkway - park on a driveway” issue that only matters intellectually but my HCD (hyper curiosity disorder) requires an answer.