Thread: Bedini SG
View Single Post
Old 12-13-2012, 11:36 PM
mbrownn mbrownn is offline
Gold Member
Join Date: Jan 2011
Posts: 1,638
Originally Posted by harctan View Post
I have a question that's been bugging me for the last few days. One of the things that I find interesting about the sg motor is how the input power reduces when it is loaded, which is opposite to the conventional motor behaviour. Having watched Electric Motors Secrets I deducted that it was because there was no back-emf or at least much lower than usual. But if I use a reed switch to trigger the transistor instead of the trigger coil then that effect is lost and the input current increases under load. I would like to know what is the difference in these 2 ways of triggering that creates so different results.
With the electronic trigger its about how many pulses per second. If there is 1 unitt of energy in each pulse and and it pulses once per second you are consuming just 1 unit, but if it pulses two times per second you are consuming two units. this is because you have a fixed pulse. With a reed switch the contact is made whenever the magnet is close so at a lower RPM the pulses are longer in duration and more power is consumed.
Reply With Quote