5/10PCS 19X12MM Magnetic Levitation DIY Coil High Quality Copper Coil Electromagnetic Induction Experiment Coil (5)

A little expensive, but these coils are precision made, very tightly and evenly wound coils.I'm using them to make a mini but robust DIY, hand crank, axial flux generator. I'm using 8 N42 Pie Shaped magnets and 6 of these pre-wound coils. I removed the steel core to avoid cogging, but that's just for my specific project, which is a 3 phase generator.I easily got 5+Volts at 1+ Amps from one coil. Using all 6 coils I can easily get 30V at 2-3A. Using these like this, they do have some resistance but that's to be expected from a coil this size.

Since there are no SPECS, I tested and measured the following:27 Awg wire4 Ohms2.32 mHMax about 1A at DC, could push maybe 1.7A with AC depending on frequency and duty cycle and cooling.47 to 60 mTeslaI hope this helps someone deciding.

The coils are well wound. The problem I found was vary basic. The wire lead that comes from the center (start of the coil) was broken off on 2 of the 5 I bought. The very tiny gauge is fragile and when immobilized as it is, it bends and breaks off with few flexes/bending. They need to immobilize this lead with a piece of tape or similar until a customer is ready to install the coil in a project stopping any bending/breaking.

Good quality, but did not have specifications (resistance, inductance, ...etc., but can measured using instruments)

All OK

Failed first test, going to retest.

Lack of specs, but well made.

Tested up to 5V direct input so far on one coil. Managed to get some electromotive force generated. Will need to continue experimenting more to get more force with minimal coil heating.