A question for Ron P and other HCCT fixers. I have one that will spark a coil without the ammeter hooked up but when the ammeter is connected the needle goes full scale and there is not enough juice left to spark the coil. It has the standard Weston meter.
A quick check of your calibration on the ammeter and overall condition of your HCCT can be made by connecting an 1156 Bulb to the HCCT by connecting one connection to the bottom coil connection and one connection to the top side connection while leaving the spark connection open. Turn the crank on your HCCT rather briskly and you should be able to get the bulb to light up a dim glow and your meter should read bout 1.2 amps. If that checks out then you probably have the current set way too high on the coil being tested and you can believe your meter. If you get something radically different with the 1156 bulb test then report back here.
John With the 1156 hooked up the bulb gets a dim glow and the meter shows 0. The coil used in the test had been set up on another HCCT and double checked on a second one.
Have you checked the wiring. Your test results are contradictory. A bulb is near zero resistance when cold (before you start cranking) and it produces absolutely NO CURRENT????? when cranking while a coil which typically has a higher starting resistance than the bulb is producing over 2 amps. I think you need to check the wiring of your HCCT carefully point to point and also connections to those wires for something intermittent or wired incorrectly. Your test results with the bulb seem to make little sense to me.
It sound like your meter is wired wrong. It should go in line with the coil under test. "That measure current through the coil." It sounds like you have it wired in parallel with coil to ground as if you were measuring the voltage across the coil. That would make it a dead short across the coil pegging the meter and allowing nothing to go through the coil under test. A possible problem could be that one of the terminals on the back side of meter has been crushed and is shorting out to the frame, or the wire terminal has slipped loose and now its touching the frame. Some how one of the terminals is touching the frame of the HCCT.
I'm working on the meter of mine at this time, and I can see it happening very easily if your not careful.
I am in the last stages of building an HCCT by Gary Tilstom's plans but have a question regarding the wiring of same. His plans call for:
However, Ron Patterson posted this:
Does either schematic work, if not which is correct?
They both work. Both make a complete circuit from the field coil though the coil and amp meter. Ron's shows more optional stuff on it like the magneto terminal, horn terminal and spark plug tester.
Gordon, heres the one I finished about a month ago. KB
Thanks Jim,I'm obviously weak when it comes to electronic knowledge!
What can mess you up is the "Magneto" Terminal / Inductor on the hand drawn diagram. Think of it as not being there. You will be safe. The main thing is to think of a loop for current to flow around in. Magneto to Meter than on to coil than back to Magneto. It does not really matter if meter is in front of the coil or after the coil under test as long as its in the loop somewhere.
I like to think of it as measuring the current from the source to the load.
One more thing.. The Amp meter is like a dead short. It draws off a small sample of the AC current to drive the meter, and passes the majority on to the load. In the meter it has to convert AC to a small DC current to move the meter needle in one direction.
Thanks guys. It was wired backwards. A friend of mine had the thing and wanted me to look at it to see why it didn't work right. Unfortunately
he had someone "fix" it. Everything is a cobble job on it. It sort of works now.
When I built my coil tester (the one the drawings are of) I purposely omitted the spark plug testing function as it doesn't really test the plug. A plug can fire on one of those yet fall off when placed under pressure. It isn't much of a test. I use a tester that places a plug under pressure and will see if it fires. The test pressure varies based on plug gap. Your mileage may vary.
But Gary, its pretty to look at! I use the pressure test also. KB
I'll give it that, it does look cool. G