wiring box mounted on gen

[methanolcat]

I have mounted a box on the side of the baldor/ rewound gen.

  Is it a triple pole triple throw relay that I need to find for this to be able to switch from star and delta and not use individual relays as they may cause a problem?

   With peaks of around 4kw, as far as current and voltage go what should I be looking for in a relay?

   Any help here from Zubbly as I know this is what you have already been working on, what kind of circuit would work for switching the relay on and off.

    Along with rewinding the baldor I threw in 3 extra coils of much smaller wire that could provide power for some kind of switching circuit. I tested voltage on these smaller wires as well and here are some of the results.

    64.2 volts at 654 rpm

    44.6 volts at 494 rpm

    33.7 volts at 351 rpm

    21.7 volts at 256 rpm

    11.2 volts at 132 rpm

    8  volts at 95 rpm

   These numbers are with all 3 coils wired in series, so if the voltage is too high I could use only 1 or 2 of the coils or possibly parallel them

    Maybe even use 1 coil for a trigger, or sensor for rpm some how if possible. I have looked and found some possible circuits on this board but not really sure which one would best suit my needs.

    Would a circuit run on variable voltage with use of a zener diode to limit the voltage or would that not work?

 I could run only 3 wires down the tower if I could get all I need in this box for switching star and delta



 to simplify connections I used these terminal strips, for 1,2 and 3 star or delta I would always leave the wires in the lower left outlined in green just as they are. Other connections would be changed at the lower side of the top strip and the strip in the center.



lathe testing being done at different rpm's no load

[tecker]

 Electrical flexability is a very good aproach to a wind alternator and doing this at the top is tricky but should be worthwhile.

[tecker]

My experiences with a large Nema 4 box dictates a nema 3r cap on the top as heating and cooling wastes the top gasket fast .Also the big box will be making violent moves left and right put your heavy contactors and such at the piviot point . Looks like you have all the skills and equipment to take care of any thing that goes on . Nice setup and a impressive build .

[methanolcat]

thanks tecker

  All of the gaskets I am using on this I cut myself from automotive grade materials, which should be able to stand the test of time. Only time will tell that, but it's very strong and tear resistant. It's a mixture of buna type rubber and cork.

  I never really thought about the weight of a heavy contactor affecting anything but I did notice that the front of the box near the shaft end is going to need some kind of brace to be made for extra suport. I'm thinking about attatching the brace to the front of the motor since there is a tapped hole near there.

[Ungrounded Lightning Rod]

Not just the weight.  Strong acceleration may affect the operation of the contactor - especially when it's in the state where no current is going through the coil.

You don't want your contactor to try to switch on its own (and thus disconnect the alternator from the load or do an unintended delta/y switch) just when a gust makes the mill suddenly yaw.

[TomW]

UGL;

Good point! Be the kind of fault that would make you crazy trying to track it down after the fact.

Cheers.

TomW

[RP]

It might be a good idea to orient the contactor so that the pivot axis of the contactor  is perpendicular to the yaw axis (even if you have to mount it on a 90° bracket).

[methanolcat]

actually the wind mill is not going to yaw out of the wind, the blades are going to change pitch in higher winds but that is another story all together, but it may still want to move rapidly back and fourth in turbulant winds so it's something I will definitely think about.

[Seaspray0]

including the extra windings for your circuitry is the best thing to do since your main windings are subject to the loading of the battery and not a good reference.  I designed a simple comparator circuit that used some resistors, two potentiometers (can be replaced with resistors once the adjustments are done), a regulator and an op-amp and gave it to someone here.  I basically had it set to engage the delta setting when the voltage was high and stay that way until the voltage reached a lower point (avoid the relay chattering on/off at a single cutover point).  I wouldn't worry too much about the motion of the relay when it activates.  Mechanically, most of them use a plunger through the coil and they snap open/closed very fast.  The mass of the relay housing absorbs the shock well.  If you're interested in building your own circuit, I can send you the basic idea for a controller circuit.  jamesa01(at)sbcglobal(dot)net.  

[(unknown)]

i would be interested in that circuit if possible.  colinroberts(at)sympatico(dot)ca

thanks