Open Source Generic Pulse Motor Testbed

[Yucca]

Hello All,

I've developed a microcontroller based system for accurately testing and controlling pulsemotors and thought I'd share it in this thread. It's a work in progress, but the basics are all in place.

At the moment the user can adjust the pre pulse delay (in tenths of a degree). And also adjust the pulse width (in tenths of a degree). The unit also displays the RPM.

My idea is that it will help me hunt for optimum configurations in a controlled and repeatable manner. Whilst measurinc coil input power and BEMF output power.

Also a small bip is sounded (optionally) once per rev. The tone of the bip is proportional to the speed, good for tweaking while listening for RPM changes.

If anyone wants to build one then let me know, the source code is available open source so can be adjusted for more disc mags etc.

It uses this controller:
http://www.nuelectronics.com/estore/index.php?main_page=product_info&cPath=1&products_id=1

and uses this screen:
http://www.nuelectronics.com/estore/index.php?main_page=product_info&cPath=1&products_id=10

(The screen is sold out at the moment, but they will probably have more in soon)

Here's some pics:

[Yucca]

The user interface, it uses a small rocker joypad switch on the screen board. Push left and right to adjust pulse width, push up and down to adjust delay.

[Yucca]

It has LED strobe lights with black&white tape markers over the mags, this enables you to see the timing, green is the pre pulse delay, red the coil pulse.

[Yucca]

At the moment the testbed is set up with a peculiar coil, that propells diametrically polarised neo discs. The coil is S N N S as you pass through it, I fire a small pulse just as the mag passes the middle, the S pole facing forward gets attracted forward, the N pole at the back gets repelled forward.

I am getting 300RPM from ~10mA at 7V drive power. My BEMF collection is only about 15% of coil energisation, I'm not recycling it yet, just measuring it.

With it being air cored it gives real spikey BEMF, It tops out at 400v, but that's only because my FET has internal protection diode and it cascades at that voltage. When I fire by hand using flyleads it kicks back at well over 1KV. At the moment I'm collecting BEMF using 5*1n4148 into a low ESR electrolytic (470uF 200V) from a switch mode PSU. By timing for 1minute and measuring voltage rise I can calculate harvested BEMF energy fairly accurately.

A thread on this coil config (DEK UCC) is here:
http://www.overunity.com/index.php?topic=6727.0

I'll be swapping this peculiar coil out soon for a cored coil with close passing magpoles ala Bedini soon.