Test Coil, Country flag and Turbine blades

I made a test coil winder earlier and today i made one coil with 37 turns. I didn't add any varnish coat but the coil is difficult to remove from the fixture ... I shall make another simple jig tomorrow that will ease up removing the coil without destroying it.

"Roman" at cnczone posted a helping post in my thread about Coil winding , following are his words for everybody who need to wind the coils:

"About your coil winding jig, I have done many coils and even worked in an electrical motor shop that had a few commercial coil winders.

Suggestion 1; Put the jig on the end of a portable electric drill (with a speed control) and then it can wind automatically. A lathe is also good if it has a low speed.

Suggestion 2; You can paint the coil with varnish or nail polish every layer as you wind it, which will then be a reliable solid coil when done. However this will stick badly to your coil former. If you made the coil former from polyethelene (like food chopping board) the glue will not stick and you can make solid coils then pop them off the former. You might need a small taper on the middle round part, to slide out of the coil.

The magnetic forces on the windings will be high, so somehow they need to be set in resin or varnish. Otherwise if there is any air in the coil the windings will flex and rub because of the magnetic field and soon wear through the insulation and fail.

If putting a dry winding in resin we would put in a vacuum chamber to make sure the resin goes through the coil and no air is present. It is easier to varnish the coil as you wind it, every layer, so I would go for the polyethelene former and do that. Varnish type is not that important, quick dry nail polish is an acrylic and will be strong and bond well later when you set the hard coil into the former with resin."

I hand rotated the magnetic plates and got 1.5Volts (don't know about the RPM) with single test coil. Tomorrow i shall borrow a stroboscope and will plot a graph between RPM and Voltages. following is the formula to get estimated cut in voltages.

Required Cut in Voltages= VAC(of test coil at cut-in speed) x No. of coils/phase x1.732(multiplication factor for 3 phase)x1.414 (DC conversion factor) - 1.4V (diode drop)

The cut-in speed i shall keep around 150~200RPM. You can see pictures of furling flapper that is turned into flag of my country.

Three PVC blades 6feet each worked out by my brother one year back . The blades are big you can see pen kept on the center blade for comparison.