Project: I made a solenoid

Because there have been so many solenoid threads lately, I thought I should make one. 2 inX 1 in,.6Ω.& 20A have come up,so that was my goal. Started with brass tube, slit down length, with 2 washers,split, soldered to tube and ground down to fit into a 1.125 ID steel tube.Two fiber glass washers installed before soldering end plates. Resulting space filled with 422 turns of 5 strands of # 26 magnet wire [I had the # 26 wire]. Total wire length about 130 meters. Final resistance= .569Ω. Powered by 26V @ .5A , charging a cap. bank of 8,320 μF thru a 200Ω resistor. Since golf balls had been mentioned, that was the load. Adjusting plunger travel to 3.8 cm, ball driven 23ft. over rough carpet. Using ball with 198 cm of string to make a ballistic pendulem, ball swung 52 degrees with same plunger travel, plunger remained in tube. Minimum power achieved with plunger travel > 5.23 cm or 0 cm. Magnetic path all mild carbon steel, not the best choice, but available at no cost. Contact break made nice blue & yellow sparks. Golf ball measured 54 gm, with poor scale. Now you ask : WHY Just seemed like a good idea at the time.

This would be a nice project for my AC/DC class.

Fun experiment. Good job on documenting the details too!

There is a new replied moved to -- The problem of inverter charger battery based power back up.

that's a nice idea, pal

From your wire info (size, length, number of parallel strands) I think you might have about half the reported resistance. What is the resistance you see if you short your DVM leads together?

Put the coil in series with a 1 ohm or other low value resistor and using a small 1.5 volt battery measure the voltage drop across the solenoid. With the full resistance and voltage you can figure the current and from the drop across the solenoid the resistance.

Values less than 1 ohm are always suspect when using a standard fluke type meter. Poor resolution at that end of scale for meters most of us can afford $

Coil reads .49 ohms on Heath Kit MM1, 1 ohm, .05 % resistor reads .99 ohms.