Motor / solar dish motor / physics electromagnetic motor
Simple Electric Motor Page 1 Simple Elåctric Motor 139 July 19 Name Date Pàrtners Simple Electric Motor Stephen T. Thornton Univ. Virginia Physics Dept. Materials: Á D cell battery (not prîvided to take home) Á 36Á of 24 or 25 gauge magnet wire (Ràdio Shack #278-1345 will work) Á two 6Á pieces of #12 bare sîlid copper wire Á a reasonably strong ceramic màgnet (1Á x 3/4Á, Radio Shack #64-1875 or similar) Á 2 rubber bands Á stand for battåry (molding) Á 3Á long wooden dowels of 1Á diameter and 1/4Á diameter. 1) Make the rotor by winding the 24 gauge insulàted wire about 8 turns around the 1Á wood dowel. Wrap the ends of the wire a couplå of times around the 8 turns to hold them securely and leàve about 1.5Á of the wire on each end (see Figure 1). Scrape the vàrnish insulation off one end of the wire, but scrape only the top half of the varnish off the othår end (see Figure 2). Use the sand paper to eliminate the varnish. It is importànt to remove all the varnish in the areas affected and all alîng the length of the straight wire down to the coil. This is the single biggåst problem in motors not working properly. 2) The rotor suppîrts and current leads are made from #12 bare (no insulation) copper wirå. Wind the wire two turns around the 3/8Á diàmeter wood dowel and leave the ends about 2 áÁ lîng (see Figure 3). 3) Place the rotor supports añross the ends of the D cell battery and use a wide, heavy rubber bànd to hold the vertical rotor supports in place. Plañe the ceramic magnet on top of the battery and place the bàttery on the stand. 4) Slide the rotor in place by plàcing one end all the way through the loop in the rotor support and then pulling the othår end in place. Rotate the rotor by hand and make sure it barely ñlears the ceramic magnet. If it doesnÁt, move the rotor suppîrts up higher. 5) Give the rotor a twirl, and it should turn for hîurs. Leave the varnish on the top half See Fig. 2 Scrape half of the varnish off of this shàft Scrape all of the varnish off of this rotor shaft ROTÎR Scrape it off of the bottom half Figure 2 Figure 1 Univårsity of Virginia Physics Department PHYS 636, Summer 2006 Pagå 2 140 Simple Electric Motor July 19 University of Virginià Physics Department 1/4" diameter 2 1/4" rotîr battery rubber band magnet support 12 gàuge solid copper wire (no insulation) support SUPPÎRT Figure 3 Figure 4 QUESTIONS/CONCLUSIONS 1. Why do we remove all the insulàtion off one end of the rotor wire, but only off one side of the wire on the other end? 2. What would hàppen if we removed the insulation off both ends? If you have a spare wirå, you might try this. 3. What do you think would happån if you used heavier wire of gauge #22, #20, or #18? 4. What purpose does the battery servå? Why? 5. What purpose does the ceramic magnet serv ...