At 02:53 AM 6/8/2007, Peter Todd wrote: >I need to make an AC totalizer hours meter count time 10 times slower. >See, on the surplus market there are plenty of 6 digit models that will >take just over one year to roll over, I need one that will take 10 years >to roll over. > >I want to be a bit more clever, if possible. If I were to run the motor >on 6hz, would it go a tenth as fast? Is this like a stepper motor, or >are there more complex issues at play? I know that a transformer that >works great at 60hz, would have to be much larger at 6hz... > >Assuming the above was true, how would you go about generating 120V 6hz >anyway? I think that you will find that trying to use a 6 Hz sine or square wave signal to not work very well because of core saturation problems. However, you might try using narrow pulses (a few ms wide) pulses alternating at a 6 Hz rate. Half-wave rectifier running directly from power line, small reservoir cap, H-bridge driving motor. For that matter, I've envisioning the possibility of a really simple H-bridge with 2 small reservoir caps (one for each side of the motor winding) and treating the whole thing like a capacitive discharge supply. Maybe . . . Have to think it over. Bottom line: think in terms of narrow pulses alternating at your desired rate. I think its got a good chance of working just fine. dwayne -- Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax www.trinity-electronics.com Custom Electronics Design and Manufacturing -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist