Currently I have a gasoline generator (2 kW 230 Vac single phase), which has an electric starter. I'm searching for a potential replacement, but the brands I like doesn't have one around that power level with an electric starter.

One idea I have is to excite the stator (via the 230 Vac output pair), as well as the rotor (single pole and winding). And that would be to excite the stator with some DC voltage and then the rotor with the required DC voltage to start the engine. Is the winding shape of both stator and rotor a limiting factor on this? Should something else being considered? I'm also not sure about how to control the direction of movement.

Before spend money on a new generator (before it's needed) and start to trip circuit breakers off, I want to make sure that there is a chance that this will work.

EDIT, for clarification:

  • I have a 230 Vac inverter, single phase, 50 Hz (Europe), which can provide more power than the required to make the rotor to spin continuously;
  • A 650 W electric drill is able to spin the rotor slightly faster than the starter but still slower than 3000 rpm;
  • I have a few alternatives (replace pull cord by electric motor, replace gasoline engine, build the genset from parts, ...) as a backup but I want to pursue the idea of this question, if feasible/cost effective.
  • \$\begingroup\$ If the alternator runs at 240 VAC, you'd need about a 240 volt starting battery. You also have to rewire the alternator. Not practical. \$\endgroup\$ Commented Jun 2, 2023 at 23:08

2 Answers 2


You'll need to add a start winding or shaded pole because otherwise it'll be like a 1 cylinder steam engine, won't be able to develop any force when piston is at top or bottom.

The rotor is probably DC but the stator is AC and will need to be driven to "lead" the stator so that the rotor is always trying to turn into the stator. That thing that does that for you is called a commutator and is found in that starter motor you're rejecting. Thus you will need to be your own commutator, and generate an AC or quasi-AC variable frequency signal phase-locked to the rotor + lead. You will also need to be boosting (as in buck-boost) because it's wound for a much higher voltage.

But yeah, pretty straightforward other than that :)

Wouldn't it be cheaper to take it to a shop and just have it fixed? You say it's not made anymore, maybe it's old enough to actually be good. And thus worth fixing.

  • \$\begingroup\$ If you can access the flywheel or alternator shaft, maybe you could spin it with an electric drill. \$\endgroup\$
    – PStechPaul
    Commented Jun 4, 2023 at 7:43

Alternators are usually designed for low torque at low rpm in order not to kill the motor. That's not what you need for starting it.

That's on top of the non-trivial commutator issue mentioned by @Harper.


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