I found the following pictures and equivalent circuit of the Rühmkorff induction coil:

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Can someone explain the operating of this coil in a step by step fashion?

  • \$\begingroup\$ Capacitor I think initially charges and and "some how" shorts T1 and T2 and this creates the first spark. But then I couldn't figure out the rest :( \$\endgroup\$ – user1245 Feb 13 '19 at 12:50
  • \$\begingroup\$ Capacitor will short its terminals so yes but what causes T1 and T2 to close? Is this a relay? \$\endgroup\$ – user1245 Feb 13 '19 at 12:52
  • \$\begingroup\$ Yes the current charging the capacitor create a magnetic field and the current shorting the capacitor will not. How about what moves T1 towards T2? Is that a relay? \$\endgroup\$ – user1245 Feb 13 '19 at 12:55

It's pretty straight forward:

Spring terminal T1 and adjustable terminal T2 are adjusted so that they are in contact when no current flows.

When you connect the battery to the device, current flows.

This causes a magnetic field in "soft iron core 1."

That pulls on "soft iron pole," causing it to move. This opens the connection between the two terminals.

When the connection between the two terminals is opened, the magnetic field collapses, and the soft iron pole moves back to its resting position.

The circuit is now connected again, and the cycle repeats.

All of this happens in the primary coil of the device.

With the primary pulsing on and off, a pulsing high voltage is generated in the secondary coil.

The ignition coil on the old Ford model T worked the same way.

It used a vibration system to generate high voltage constantly.

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  • \$\begingroup\$ Thanks btw I found this demonstration youtube.com/watch?v=vOTmbbl3jEg \$\endgroup\$ – user1245 Feb 13 '19 at 13:00
  • \$\begingroup\$ That stopped the process of helping the OP understand... \$\endgroup\$ – Solar Mike Feb 13 '19 at 13:40
  • \$\begingroup\$ It would be similar to a NC relay in series with coil current \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 Feb 13 '19 at 14:12

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