single phase conversion

[windrules]

Hi guys I have been flying my 3/4 hp single phase genny for a few months with using just the run windings,each winding to a rectifier then paralleled and seriesed the rectifiers to DC. I pulled 13 amps at 12 volts at about 25mph winds.Last night I soldered wires onto all the start windings and now have 8 pairs of wires 4 pairs a different colour for mains and 4 for starts,all outside the can.Now comes the question, to determine series and parralell windings can I put the jenny in a lathe and work it all out with a voltage meter by picking 2 start windings and check the voltage of one at operating speed, then select the combination to double voltage? I assume but could be wrong that if the voltage here drops to nothing or near nothing I would have it backwards and just reverse 1 wire to get it right.Then to do the parrallel thing the voltage should remain the same.I think I should this way eliminate 3 rectifiers whick should give me better output.Then do the same with start windings and parrallel the two together and hopefully get about 20 amps from same machine.

Hope this makes sense and want to know if this is right!!

Thanks again and best regards,

Mos

[Jerry]

Hi Mos.

Is your motor 120 v?

The lathe idea is a good one. Chuck it up in the lathe and check the voltages from the starts.

In some motors there are 2 large start windings and 2 small. If this is the case with yours you'll get 2 coils reading twice the voltage of the other 2.

Next step then is to perelell the 2 large windings, then siries the 2 small windings. After siriesing the 2 smalls perelell those with the 2 large.

This will be = to 3 large start windings in perelell.

I then typicaly do a siries perelell conection with the runs. They are all equal.

I've seen around 60 amps from a 3/4hp motor this way. However this was at 45 mph and for a shot time.

                        JK TAS Jerry

[Ungrounded Lightning Rod]

Yes.

The meter produces negligible load so you don't have to sweat voltage drop from it when figuring out hookups on a test bench.

Connecting the coils of a given phase in series before a single set of rectifiers rather than connecting multiple coils-with-rectifiers in series reduces the number of diode drops in the string, improving efficiency (resulting in lower cutin and higher charging currents at a given wind speed).

Of course the start and run windings (being different phases) should be rectified separately (as you seem to be planning to do).

Sounds like you have it down pat.  B-)

[windrules]

Hi Jerry thanks for comments. The motor was 240 volt and the start windings are all the same.

Update to this is that last night I did the lathe bit and found this a very inspiring exercise and all worked as planned (which doesn't always happen with me).I seriesed and paralled the mains and the starts as the starts didn't seem to put uot eneogh volts in parrallel alone.The lathe made it a quick simple proccess and would recomend it to anyone,the only thing I wasn't sure of lathe rpm.Hooked it up to a small 12 volt battery and it put out a steady 8 amps after the mods and I think it should go realy well with a prop but have to wait a couple of days before I have time to put it back up. Thanks also Lightning for your imput but already had done the lathe bit by the time I got your posting ,good to confirm that it worked realy good.

Thanks again,

Mos