Hi all,
Im new to this group, and sadly to say I havent viewed the DVD. But im really curious and would like to get one thing straight here about the back emf. just listened on the sterling d allan interview...

Someone please correct me if im wrong.

Lets imagine 2 experiments. they are very basic and similar. they consist of an electromagnet, a powersource and a switch.

in experiment number 1 we activate the electromagnet and exert a pull on a target, in this case a piece of soft iron. If we have a whole bunch of measuring equipment, we can take readings of all sorts of things, but basically we can see that it takes a certain ammount of electrical energy to get some mechanical work done (pull the target with xx newtons)

in experiment nr 2 we have a permanent magnet instead of the soft iron as a target. so when we switch in the electromagnet the magnet is drawn closer ( if the emagnet is wired for pull N/S) . And if i get the thinking right by what is presented here, then just by moving the perm.magnet closer we increase the magnets field strenghth and hence there will be a counter emf produced in the electromagnet? so if we design the second experiment to show the same ammount of MECHANICAL work being done, there should be MORE electrical drawn from the powersource in the second case?

Is this so? If it is then we have a really nice thing coming up
I just want it confirmed, because i have a few very nice ideas for a motor that will use this idea.

Lars