RF couple it. ----- Original Message -----=20 From: "Koen van Leeuwen" To: Sent: Thursday, November 27, 2003 5:54 AM Subject: [EE:] Transferring power to a rotating circuit Hi all, I have a circuit mounted on a fan, doing about 3000 rpm. This circuit has to be powered with 5v, 30 mA. I can't use brushes because they slow down = the fan too much. I tried to make an "open transformer": an open coil (not rotating) with a smaller coil with iron core inside it (not touching the other coil, and rotating). Both coils have ~30 windings. Using 50 Hz 5v 500 mA at the primary side,=C2 only 300 mV shows up at th secondary side with short-circuit current of 1 mA. Should I use a higher frequency, or just make the coils larger with more windings? (or is this never gonna work and you have a better idea?) Thanks in advance, Koen van Leeuwen -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu