Coil tester.

[Kbeitz]

I found this old coil tester many years ago at our local junk yard.
I have googled for it many times and never found anything.
I have ask many saw shops if they ever seen or heard of one like it.
No one has but everyone wants to buy it. It works great.
Has any one here seen anything like this ?



 

[Ljohnsaw]

Interesting.  So, you plug it into an A/C socket and hold the coil up to it and the spark plug keeps on sparking?

[Kbeitz]

Interesting.  So, you plug it into an A/C socket and hold the coil up to it and the spark plug keeps on sparking?

If the coil is good then yes...

[Rural]

Neat,there have been many times when I needed on of those! I wonder, does it work on the new electronicly fired coils?

[Ada Shaker]

That's funny and very old school, but doable. Reminds me of the turn of last centuries tramways equipment. A variac transformer on the primary side would give an indication of how good or bad the coil was. Looks kind of home made though. Seems to use eddy currents from the iron core to induce an emf into the coil by completing the core circuit using the chainsaw coil. whether or not they can be used on modern coils is dependent on the leads that comes out of them. In general, the copper coils built into them haven't changed, the leads coming off them seem to be silicone/carbon or something similar and have changed over the years. Hence a variac to increase/decrease the input voltage would be beneficial in determining coil condition, IMO.

[Al_Smith]

In theory if you hooked that thing up to a source of AC voltage it would alternately change the pole pieces from positive to negative .In effect acting about the same as movement from the permanent  magnets on a rotating flywheel of a small engine ,passed the poles of an ignition coil .

One coil of the tester is likely wound right hand while other is wound left hand there by making one positive the other negative .To the ignition coil it would seem as a  rotating flywheel at a very high rate of speed and should produce enough induced voltage to drive the ignition coil into saturation  which would be maximum output voltage .

[Kbeitz]

What ever.... It works great.

You just need to watch what not to touch
and that is hard. You need to hold the coil tight
to the tester with out touching the plug and
the plug needs to touch the coil.
So far it has worked on every coil type
that I have tried except the
Tecumseh Oh160 Engine Solid State Ignition Coil

[sawguy21]

 :D :D I hated that system.

[Kbeitz]

:D :D I hated that system.

But they sure was great tractors...

[Ada Shaker]

Don't think it really mattered if it were ac or pulsating dc the thing would probably still work. A full bridge rectifier could be connected to the input and it would still work. The fact that the plug has to be touching the iron core would be an indicator that the core is grounded to earth, (return fault path). The dielectric (air) ionizes and breaks down when the secondary voltage reaches the required potential for breakdown. Connecting a variac to the input would give a good indicator at how good or bad a coil was, dependent on the input voltage which is proportional to the output voltage (number of turns on the secondary coil). Different coils could be measured independently in this way.