From: "David VanHorn" >> >> No. It's only hard to turn if the output has a LOAD. >> Otherwise no work is being done. > > > It's quite noticable, even with no load. The load makes it even harder. Finally got some time to play with it a little more. I found the alternator's PDF from bosch and it does have an internal regulator. I connected the 12V battery to the smaller post and the pulley did become harder to turn. In fact, before I was using my dremmel to turn the alternator shaft. With the power on, the dremmel stalls and doesn't turn the pulley. I had to use my power drill to turn it. I don't know if all regulated alternators are like this, but I was monitoring the output (big pole) on my oscope while hand turning the pulley. While the voltage level went up or down depending on the speed that I was turning the pulley, the DC output seems almost noiseless, which I found very nice. One other side effect is that the pulley become a magnet. I wonder how big is the magnetic field generated by the alternator when at full speed? This is for my robot, and I will have magnetic sensitive components on the same platform (devantech compass for example). Cheers Padu -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist