Engine starting_electrical

Look, if you want a load of cheap alternators to play with then meet me outside the back door of Halfords in Basildon in about 10 minutes...... <splutter>

You need some power to turn the engine over (so that the alternator generates enough power for the ignition). You'd need a crank handle (or a kickstart - like a bike).

Just spotted your other thread - realize now you want to use the alternator to turn the engine. Other thread tells you why not.

You seem to be starting into the wonderful world of alternative energy, great. First you must get your terms and machines correct. An alternator can only make electricity. First it makes 3-phase ac and then it rectifies it to dc. An alternator must have a battery in the circuit to work. A starter can only start motors, it makes a terrible generator. For very small motors, like a riding lawn mower, Bolens had a starter-generator a long time ago. The generator was dc, I'm sure. In the days of old, all cars had dc generators. They would motor, but not strongly.

mike; an alternator can run as a motor. pac

Hello pac

It can, but only if supplied with AC. As mike k says some small engines have starter-generators (not starter-alternators).

Though the original post is about vehicle engines, might be worth adding that engines used for power generation via an asynchronous alternator can do it. I'm pretty sure a bog-standard motor is used (much cheaper than a synchronous alternator), and when run at just over synchronous speed puts out power to the mains. For starting, it acts as a motor. The motor rated power is of course similar to the engine power output, so more than enough to crank the engine. Disadvantage is it cannot work independently of the mains, even if the engine can be started (conventional starter/battery).

Cheers......Codey