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Wasted spark ignition
Coil on plug style wasted spark transformers, so (beside the 2 pin power-input connection) each transformer has 2 HV connections
- one directly to sparkplug
- and the other to the cylinder-pair (1-4 and 2-3).
The transformer cores are firghtening small. We were note sure they are inductive (not CDI) operation. But they seem to work well with inductive.
Each transformer has 2 pins, that means it cannot be "active coil". So the inputs are power-inputs for sure.
- NEC 000130 5009
- 0040 100 502 0000
- Beru Korea
Similar type with slightly shorter HV connection:
- NEC 100730
- 12V GCL209
- DENSO SPAIN
The 12V text is promising, it would not make sense for a CDI coil.
Also, the engine was running with the 2nd transformer, with shorter than 3ms dwell (2.5 ms was used ? guesstimated without measurement). But with the shorter HV connection, the spark sometimes happened at the wrong end of the sparkplug.
2.5 msec (VBatt=14V) seems to be a bit too high current: Using 3 x 0.1 Ohm 5W in parallel (as measuring resistor, in series with one coil's primary winding), at 1200 RPM
- (9mV / 0.033 Ohm) DC mean current was measured (on ONE coil, that is fired every crankrot), which means mean current while the coild is charged:
- Idc = 0.009/0.033 * 60000/1200 / 2.8 = 4.87 A notes:
- the 60000 msec / 1200 is the time of 1 crankrot at 1200 RPM
- 0.009 / 0.033 is the 9mV / 0.033 Ohm
- / 2.8 is for the the 2.5msec actual dwell (as read from LCD; higher than 2.5 msec because the VBatt was lower than 14V
The peak current is twice as much, that is 2 * 4.87 = 9.74 A, which is a bit high (5..8A is usually best)
Marcell recommends trying 2.1 msec dwell and measuring again.