STEORN DEMO LIVE & STREAM in Dublin, December 15th, 10 AM

[gravityblock]

Gawd... C-mon GB, I was just going to let it go but you keep insisting.

Think of this:
1: Turn your bedroom light on for 1 minute, then off for 1 minute, do this for 1 hour.
2: Turn your bedroom light on for 1 second then off for 1 second, do this for 1 hour.

Which one used more power?

The correct answer is ...... um..... 2

Compare the total energy input of one complete turn of the rotor at a higher RPM to one complete turn of the rotor at a lower RPM.  You will notice there was less input energy for one complete turn at a higher RPM than at a lower RPM.

You're bedroom light anology is wrong.  Both tests are doing it within the same 1 hour period or duty cycle.  At a higher RPM it is making a complete turn much faster and would be equivalent to less than 1 hour as compared to a lower RPM.  You can't compare the two within the same 1 hour period because the frequency is increasing at higher RPM and the duty cycle is decreasing.

The 1 hour represents the duty cycle or one complete turn.  The 1 minute and 1 second represents the frequency (how long it takes to make one complete turn).  Your bedroom light analogy keeps the duty cycle the same for both tests.  ROFLMAO.

GB

[captainpecan]

First, nobody seems to have pointed out yet that the nearly 1 henry inductance comes from multiple toroids in series, so each individual toroid would be a smaller value.  This may mean something regarding core material, but i'm no expert on this. 

Yeah, I've been keeping that in mind.  But you must realize, there is a set of magnets for each coil also.  Therefore you must figure the system properties AS IF you had one set of magnets and one core.  Because for every pulse, each set of magnets have to do their job to get each toroid to saturation.  So basically, I don't everyone is forgetting that steorn is using 8 coils, they are just trying to find the right match for 1, then use that combination on all of them!

[gravityblock]

I'm sorry GB, but I edited my post after you quoted me, so your quote was incomplete.

At higher frequencies, the on pulse is shorter, so there is less energy per pulse.  However, the off time is also shorter.  This means that the next on pulse comes sooner, resulting in the duty cycle and input energy being constant regardless of the frequency or RPM.

If we change the control circuitry to increase duty cycle, then input energy increases.  Or we can lower input energy by decreasing duty cycle.  However frequency or RPM alone do not change duty cycle in these pulse motors as far as I can tell.

But don't believe me or anyone else posting on here if you don't want to... and don't trust your own memory, because we all get things muddled up sometimes.  Go research duty cycle and what it means, or check out this link.

http://en.wikipedia.org/wiki/Duty_cycle

Read the wiki article on duty cycle and you will see the duty cycle is not constant and changes with the pulse duration.

I've already said the duty cycle is the inverse of the pulse width.  As you approach a 0% pulse width, you will be approaching a 100% on time.  One duty cycle at 1% pulse width is using less energy than a duty cycle with a 99% pulse width. 

Duty cycle could be based on the pulse width or one complete turn.  The pulse width for the duty cycle is technically correct, but I was trying to simplify things by using one complete turn to show that a higher RPM uses less energy on 1 complete turn as compared to a lower RPM.

I said in this post #1307, http://overunity.com/index.php?topic=8411.msg220857#msg220857 if we used multiple reed switches or a reed switch substitute and alternated between the reed switches we can increase the RPM because the reed switch won't be continuously on.  Multiple reed switches means a higher RPM and less input energy.  Alternating between every other coil means a higher RPM and less input energy (The coils would need to be very close to each other in this case).   There is a lot of ways to improve this system with more coils, switches, magnets, larger diameter rotor, etc.  Sean said "theoretically there is no limit", and he is correct.  The only limit is what is in the system.  Talking about the 100% on time with the reed switches and coils is irrelevant.  That does not limit us in any kind of way.  What does limit us is limited thinking and I won't be a part of that.


GB

[penno64]

@Ossie,

How's your motor going ?

I picked up one of the automotive Hall Effects from Jaycar.

Can you please describe how you picked out the magnet ?

Kind Regards, Penno

[exnihiloest]

No it doesn't. When the magnet is approching a coil, the coil's circuit is open so there is no current. Then at TDC we saturate the core. Since the core is fully saturated it's "invisible" for the magnets and vice versa.

Not so simple. I agree that "When the magnet is approching a coil, the coil's circuit is open so there is no current" but it is not the point. The problem appears when the coil is powered.
"we saturate the core" or "the core is fully saturated" is no sens if you don't say in which direction. When you saturate a ferrite in a direction, it remains not saturated in a perpendicular direction, and partially saturated elsewhere.
As the permanent magnet and coil fields cannot be perpendicular, they have always common colinear field components thus they have conventional action on each other via their fields.

Just put a simple saturated toroid and a magnet in the FEMM simulation. Does the field lines of the magnet penetrate the toroid ?

The saturation model must include the direction of the saturated magnetic domains.
A "simple saturated toroid" is not a "real saturated toroid".
Unfortunately for your thesis, in real life "simple saturated toroid" do not exist and "real saturated toroid" do not respect Steorn claims for the obvious reasons I mentionned.