A month ago: Here’s where I’m at. Chastising expected/info welcomed.
Doggone it Neal I forgot about a growler and never considered it for testing a magneto armature and condenser.
Art, I’ve heard of that before but without the detail of the flasher to cycle the coil/fencer on and off. With a good battery, that fencer would run for quite a spell and work just like the 110 plug-in fencers. Keep walking the fence to cut weeds. Mom and I walked the fence with a scythe when very young. Forgot that. Cows still got out sometimes.
I hear you Scott and Adrian about the heating. I’ll leave the primary coil more exposed to possibly? dissipate some of the heat?
I’m ahead of myself right here.
You guys provide much thought and that is appreciated. Thank you!
A month later: Finally got back to this project. With coil fussing in between times.
This is about testing the American Bosch DU4/ZR4/U4 etc magneto armatures here.
I told myself I wouldn’t post anything more until it worked and it does. I’d have been surprised if it didn’t.
The primary coil and points act as a vibrator in the circuit to give the armature the on-off-on action like a magneto would from the low tension part from the points and primary coil at speed much like a real armature tester from then or today.
One could get a Phanstiel coil way back then from A. L. Dyke, St Louis for $7.50 or use a Heinze model N coil with the HT grounded.
I didn’t like the idea of any errant High Tension voltage in the mix. It probly would’ve been fine yet I cleaned up the decent T coil I started with and put it back on the shelf.
What is the coil cycle time? The speed at which the point bounces back and forth.
That would give me an idea of how fast an engine would be running for these tests.
1. I dug in the pail for the worst T coil and it is. Worked thru that.
2. About as bad as some of the coils Matt is working with.
3. I needed to unsolder and find the screwdriver slots on the screws to get the rusty nuts off. A nasty crack running thru the top.
Minwax Wood Hardener took care of that and stopped the decay. Hard when dry, it holds the crack together for the carriage-like screws, it dries quickly and at the hardware store in town for $16.
Bed frame tester-1. The bare green wire dangling below the base is touched to the armature frame, the gear (the nut is loose), the plumbers tape or the plated brass in the cradle to wake up the armature.
And you watch the touched wire’s spark.
The black “pen” looking thing is an original ZR HT output. The yellow wire is secured between the HT brush tower and the “pen” at the threads. I’ll get back to the store and find a short Metric bolt that fits so I can do away with the “pen”.
The pair of .22uF orange drop capacitors are soldered in parallel (.44uF?) in hopes of raising the uF rating close to the .47 needed.
At either variable DC or 18V AC voltage, it still looks like a Tig welder. I need to bite the bullet and order a capacitor or five but thus far the cost is near zero.
This armature tested out very poor. Very intermittent, very weak spark. Cap or coils.
It also suggested a dead short in the cap or primary at lower DC voltage.
2nd armature. A better armature. Testing shows a cool vibrator coil. A piece of electric tape did wonders to show the spark from this armature. Slightly intermittent but not bad. Coils might be OK. New capacitor for this one since making the tools to get at it depending on the next test. This armature/ZR magneto MAY have been rebuilt in 11-42.
The camera caught the points (Tig welder) sparks too.
Sacrificing ZR armatures? No. Just testing them.
Both armatures need the condenser ends unsoldered and removed then placed back in the tester for actual coil tests.
It’s sort of like a Bosch #253 or a modern armature tester only the working parts are in your face instead of underneath the base.
