Muller Dynamo

[mondrasek]

@mondrasek: Do you have a picture of your set-up somewhere in this thread?
You still using "~200 wraps of 24 AWG" as in Reply #4102 ?
Good news that you get 16 V DC out of them ! You measured right across the DC side of the rectifier?
Just looked at an image of Romero's Rotor and his pickup-coil to magnet air gap seems to be 5mm.

Well, as embarrassing as it looks, here are a couple pics.

Yes, I only have ~200 wraps of 24 AWG on single fi coils right now.

I went back to my notes and found a maximum UNLOADED reading of 16.77V across the dump cap while running 2231 RPM.  This dropped to 8.42V with 70.7 mAmps being drawn by a small bulb.  RPM also dropped to 1675 with the bulb load.

These readings were with just one coil pair.  Those were wired Tesla bi-fi and were as close to the rotor as I could get them without crashing.  So they were ~ 1/8 inch away from the rotor magnets.

I have not seen anything to indicate that bi-fi is better for gen coils in my testing.

M.

[mondrasek]

What was your input power and rotor speed?

Sorry, but I had not set up for i/p testing yet.  I tried to switch over, but when using a DMM on the 10A setting (so as not to blow the 250mV fuse on the lower settings) the DMM created an unusably high load on the system.  The readings I have are 14.96 Vin and ~340 mAmps draw, but RPM was dropped from the unloaded (un-metered) 2231 RPM down to 1989.  So I don't know if this data is usefull or comparable to any other.

M.

[mondrasek]

Here is some more raw data.

I had to go to the pet store after posting the previous data set at 6V ptp on individual coils (not pairs).  At that time my unloaded values were:

14.96Vin .382Iin 2267RPM 5.13Vout

After returning and getting ready to set up for the new tests I double checked my unloaded condition from before again and found these changes:

14.96Vin .377Iin 2300RPM 5.20Vout

The only explanation I can come up with for this increase in speed and drop in i/p is that some mechanical (bearing) problem worked itself out.  The only other changes should have been from the environment heating up through the day.

Anywho, here is data at 8V ptp for single coils if you are interested.

M.

Edit:  Yikes!  I just looked at the graphs I posted and was amazed!  So I double checked the data I had typed into the spreadsheet and found my error.  Sorry if that caused any confusion.  The corrected spreadsheet and diagram should now be attached.

[chalamadad]

The readings I have are 14.96 Vin and ~340 mAmps draw, but RPM was dropped from the unloaded (un-metered) 2231 RPM down to 1989.  So I don't know if this data is usefull or comparable to any other.

Thanks. Rough comparison is useful as a start. Are you driving with only one coilpair? My ampdraw is more than double with the original circuits.

Regarding the slowdown of the rotor when adding magnet to the back of the coil - Maybe those magnets serve a more mechanical purpose: equalling the force of the coils thus eliminating cogging for maximum speed. But it's a pain, everytime you change the distance you have to reapply the magnets. I turn the rotor by hand at slowest speed possible to check for any drag.

[mondrasek]

Thanks. Rough comparison is useful as a start. Are you driving with only one coilpair?

Chalamadad, I am not driving with a pulse motor system like RomeroUK presented.  I am driving the rotor with a VCR head motor on a regulated DC supply.  This is so I can change the RPM more easily by adjusting the input voltage/power.  Truth be told, I have not yet found any correlation between increased o/p power and RPM (yet), so the fact that I have easy RPM control might not be a requirement for a self runner.  More testing and time will tell... (I hope)