Dear Admin,
It is possible indeed that the candle effect you describe is due to some effect of the motor.
On the other hand, the fact that you can light such a neon lamp with the Keppe motor in my opinion
doesn't prove at all that the energy comes from outside.
Classical electricity theory tells us that when you interupt an inductive circuit, temporarily a tension will be generated according to the following equation: u = L d(i)/d(t). In words: "the induced voltage is equal to the circuit inductance multiplied by the (time) rate of change of the current". For more info see for example at
http://en.wikipedia.org/wiki/Inductance That tension can be much higher than the battery voltage.
Sample calculation for the Keppe motor V1.0 (input data taken from gmeast post of April 18, 2009 "Motor test results"):
* L = 50 mH = 0.05 H (estimated value based upon my own motor tests)
* i(start) = 197 mA and i(end) = 0 mA so d(i) is 0 - 197 = -197 mA = -0.197 A
* d(t): Assume the switch opens in 0,1 msec then d(t) = 0,1 msec = 0.0001 sec
Result: L d(i)/d(t) = 0.05 * -0.197/0.0001 = -98.5 Volts. This is sufficient to light the 90 V bulb you suggested to use in that experiment.
I admit that the values used in the above calculation maybe are not entirely correct but their orders of magnitude are. Measurements on my own motor indicated that the voltage peaks that occur when the reed switch is opened are 100 up to 250 Volts. If you have a look at the post by gmeast of April 11, 2009, you'll see that he detected peaks of at least 200 Volts (second scope picture: 50 V/div and at least 4 divs for the first negative peak).
In a lot of cases, such voltage peaks are not wanted and the standard trick to avoid them is to mount a small capacitor in parallel over the switch. If you add such a capacitor to your neon bulb test set-up, the bulb shouldn't light up any more.
Based on the above, in my opinion the energy to light the bulb doesn't come from outside. The bulb lights up because of a sudden release of energy that was stored in the coil when the switch was closed.
Best regards,
J Greef