On 13.05.14 17:31, Gregg Eshelman wrote: > My folks have an electric trike with an American Bosch 12 volt motor and > a pair of 220AH 6 volt batteries in series. > > I'd like to upgrade the primitive (open windings of resistance wire > mounted on a piece of wood, and that's original Palmer equipment) speed > control with an electronic one. > > Problem is all I've found in 12 V ESC is for small motors and bigger > stuff for golf carts, scooters etc is 48 volt or more.
Gregg, this vendor, with these 12v kits, is "down under", but planes fly pretty fast these days: http://secure.oatleyelectronics.com//index.php?cPath=94&osCsid=jh87mp02kif7i5rgbu67c7aos0 If freight works out problematical, then you could just wire up e.g. a common PWM circuit from the 555 application notes, driving a MOSFET via e.g. 18 ohms of gate resistor. Don't under any circumstances forget a flywheel diode across the motor. A pull-down resistor on the MOSFET gate would be a good idea, since the bipolar version of the 555 doesn't pull as close to rail as one would like. (Using the CMOS version, 7555, would alleviate that.) At 12v, I find the IRF3205 MOSFET rather nice, with an RDS of 0.008 ohms, BVds of 55v, and handling up to 110 amps, should do the trick. (If not, use two. ;-) Google for "555 timer circuits" or "555 timer application notes". The 1988 on from Philips is a bit useless, though. Erik -- The only way to do anything about man made global climate change is to reduce the population. The way to do that is to do nothing about climate change and let nature do it for us. - eko000 http://www.abc.net.au/news/2014-05-12/scientists-have-new-explanation-for-drying-australia/5445134 ------------------------------------------------------------------------------ "Accelerate Dev Cycles with Automated Cross-Browser Testing - For FREE Instantly run your Selenium tests across 300+ browser/OS combos. Get unparalleled scalability from the best Selenium testing platform available Simple to use. Nothing to install. Get started now for free." http://p.sf.net/sfu/SauceLabs _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
