03-19-2019, 03:13 PM
It took quite a bit of force and when it released it suddenly broke free and popped out but came out undamaged:
Here is the hum bucking coil and a copper annular ring that was sandwiched between the hum coil and the field:
The field coil is wrapped in cardboard and covered in black insulating paper. The pole piece is a bit rusty and does not have a step at the pressed-in end to center it so I will have to make a fixture to properly center it when I press it back in.
The coil read open directly at the magnet wire ends so the break is internal, and I will have to rewind it. I took some measurements and the wire is 0.008” dia. over the insulation and 0.0065” over the bare wire where I stripped it, so it appears to be 34AWG with heavy Formvar insulation. The coil ID is 1.1”, the OD is 2.3” and the winding width is 1.1” and appears to be random wound.
The specified resistance is 1060Ω and 34AWG is 0.265Ω/ft. so the wire overall length is 1060/0.265 = 4000ft. The MLT is (2.3+1.1)/2 Xπ = 5.4”. The number of turns = 4000 X (5.4/12) = 8900T.
Using an 85% fill factor the #turns/layer = 1.1/0.008 X 0.85 = 120T. Using a 90% winding factor for the winding build gives a build of 8900/(120 X0.9) = 0.65”. This is close to the measured build of (2.3-1.1)/2 = 0.6”.
So now I have to figure out how to make a mandrel and guides to strip out the existing winding and then to wind 9000T of 34AWG wire. This may take a while.
Steve D
Here is the hum bucking coil and a copper annular ring that was sandwiched between the hum coil and the field:
The field coil is wrapped in cardboard and covered in black insulating paper. The pole piece is a bit rusty and does not have a step at the pressed-in end to center it so I will have to make a fixture to properly center it when I press it back in.
The coil read open directly at the magnet wire ends so the break is internal, and I will have to rewind it. I took some measurements and the wire is 0.008” dia. over the insulation and 0.0065” over the bare wire where I stripped it, so it appears to be 34AWG with heavy Formvar insulation. The coil ID is 1.1”, the OD is 2.3” and the winding width is 1.1” and appears to be random wound.
The specified resistance is 1060Ω and 34AWG is 0.265Ω/ft. so the wire overall length is 1060/0.265 = 4000ft. The MLT is (2.3+1.1)/2 Xπ = 5.4”. The number of turns = 4000 X (5.4/12) = 8900T.
Using an 85% fill factor the #turns/layer = 1.1/0.008 X 0.85 = 120T. Using a 90% winding factor for the winding build gives a build of 8900/(120 X0.9) = 0.65”. This is close to the measured build of (2.3-1.1)/2 = 0.6”.
So now I have to figure out how to make a mandrel and guides to strip out the existing winding and then to wind 9000T of 34AWG wire. This may take a while.
Steve D
