Testing T Coils with Battery Charger and More

[southfork]

Picked up some used wood coils yesterday for my future 25 T Touring project. Now I have about 6 altogether. Seems like someone told me once that the coils could be tested to see if they will buzz with nothing more than a battery charger. If I was told right, how do you go about doing that with the positive and negative leads from the plug-in charger? I wouldn't want to ruin a coil with reversed polarity or some such.

Come to think about it, I think that the old-timer who told me about this years ago said that you could run a Model T engine in a stationery position without a battery or magneto, but just using a battery charger. Is that correct?

 

[redmodelt]

I don't see any reason why not. But do not operate the coil without a load, spark plug or a spark gap as part of the circuit. You can or will burn out the coil windings. You would connect the bottom and top button on the side. Coils don't care which lead goes where as they were run on AC from the magneto.
There is more to properly operating coils then if they buzz. I suggest you do a search of how to setup and check T coils. Try a Google search. Type in "mtfca; checking coils", you should come up with more info then you will need.

 

[CharlieB]

Some chargers don't put out without detecting the load of a weak battery so that, depending on your charger, might be a problem. Otherwise it should work and would run a motor too. Of course you cound use a battery itself or do as I do and use the AC out put from a toy train transformer to test them. They were made to run on AC from the magneto but work on DC as well. The points seem to last longer useing AC also. That's a piece of coat hanger wire mounted in a vice. One AC (accessory) lead is attatched to the wire, one to the + on the bottom of the coil. Touch the neg. terminal of the coil to the coat hanger wire and spark jumps to the other end of that same wire. Bending the coat hanger wire so that the ends are approximately the same distance as the 2 coil contacts helps a lot. Beats the heck out of making a buzz box too as this does the same thing. Strictly a "does it work" test.

 

[southfork]

Good input. Thanks! Think I'll try my charger and see if it works.

 

[piewagon]

Please be advised that many battery chargers assume that the load you place on it will be a battery and nothing but a battery. Connecting a battery to an ignition coil risks destroying the rectifiers or other circuitry in the charger. I have a battery charger sent to me that died when the guy used it to try and test a T coil. The primary inductance in the T coil has a heck of a core that can together give a huge inductive "kick" back to the charger and wipe it out. Please don't use a good battery charger for this experiment. Much better to use a simple 6V lantern battery you can get at a hardware store.