star, Delta....or Jerry?

[ejl7007]

Hi,  I was told that a connection in star offers more volts but less amps, while Star gives out less Volts but more amps.  I found out, by all you wonderful volunteers who have taken the time to read and reply to my questions, that a connection known as "Jerry Rig" offers even less volts but even more amps. I.e.: Suppose You have a 3-phase 9 Coil stator.  I have seen formulas that calculate power for star and/or delta but not one for Jerry.   If Power is what we're after in the long run, why aren't more turbine builders going after the jerry connect;  Ultimately, more Juice going in the batteries, means faster charging times, right?

Sincerely

EJL

 

[ghurd]

Jerry Rig or Jerry Connection is the same as Delta, but does not have the problem of reverse circulating currents like Delta.

It is mostly (?) used to fix problems with existing coils.

If a stator is made with too many turns in Star, changing to Jerry Rig may help.

In a 3-ph motor conversion that makes too many volts and has too much resistance in Star, it can make the factory coils more usable (that's why I like it).

Some people claim Delta is better than Jerry, but it never worked out that way for me.  It could be related to how exact the magnets are placed.

G-

[Flux]

Not as simple as you imply. Yes star does give the highest voltage and for a given set of coils you can safely get more current in delta but it is not so easy to deal with this lot when you are dealing with a propeller and not some bench test.

If star gives you a suitable match to your prop then as long as the alternator is big enough it will be the correct choice. If star gives too low a running speed to match the prop than changing to delta will give a significant improvement.

The power out is ultimately decided by the energy the prop can extract from the wind, not by the type of winding.

You may have a winding that performs very well in star in low winds but runs stalled in high winds. If you reconnect to delta it will do nothing in low winds but give far more output in high winds. Which is best would depend on the winds you see for long periods. If you get lots of high winds the delta connection would be better and get you more energy. If in a low wind area you may get most of your power with small currents on light wind days. Changing to something that gives far more current on a few days of the year but gives nothing for weeks at a time may not work out best in the end.

Unless you are prepared to have some means of running in star for light winds and changing over to delta in high winds you have to decide on the best winding to suit your wind conditions.

Delta has problems and is not a good choice so in the end it means choosing the wire size and turns for a star winding to suit your wind conditions. Jerry connection  avoids some of the drawbacks of delta and is a better way to adapt a winding with too many volts than using delta. If you can cope with more leads and rectifiers then it is a viable alternative to star as long as you wind accordingly to get the correct loading on your prop to suit the average wind speed.

If you want to try a changeover winding then star Jerry has some advantages over star delta. The connection is easier to change and the high wind speed running mode is more likely to be better with jerry connection than delta.

Flux

[ejl7007]

Thank you G-

[ejl7007]

Thank you Flux.