The MintakaFulcrum

Mk 3.0

Oct. 2002

Building Instructions, Photos, and Schematics

Schematic for Switching Coil, Re-Capturing, and Using the Back EMF and Inductive currents into a cap and load.

This design was built for energy recovery of the back inductive currents by storing them into a large micro farad cap while being released into a load.

New Stator Coils

• Stator Construction Details
  
  
  • Stators are wound on a 1/4" diameter by 2-3/8" long mild steel bolt with the head ground down to 1/8" thick by 5/8" diameter.
  • Two 1-1/8th inch diameter plastic end caps were made for the solenoid and slid into place. The inner magnet end of the solenoid holds the plastic cap from slipping off because of the head on the bolt. The other end is secured with a stainless nut. Bolts work for good experiment because they are very easy to adjust the distance to the rotor and also give a good anchor for the solenoid.
  • The coil was wound with 1 continuous wind of 22 awg back and forth between the plastic retainers up to a diameter of about 1-1/8th inch thick and a length of about 1-1/2".
  • I used two identical solenoids for this experiment.
  • The resistance was measured at 3.4 ohms in each solenoid and the two were wired in series for a total resistance of 6.8 ohms.

"Self-Stick Felt Floor Savers" from Walmart. Nice coil ends. I just drill out the center for size of core.	Note here that you can see how the head of the bolt has been ground douwn to that thin metal disk.
Here you can see the handle part of the coilwinder on the right.	Notice what a beautiful job this simple homemade coilwinder does for the fifth layer of this coil I am winding.
Here it is ready for electrical tape to keep it tightly bound.	Four coils wound and ready to mount

Rotor Update

New Rotor

This is the new rotor I made for safety reasons. It has 6 stacked grade 8 ceramic magnets each 1/4" thick and four poles all north out. It can easily hold its own weight with one pole... it has a mass of 967 grams.

• Rotor Construction Details
  
  
  • The rotor is made from two pieces of 3/4" white "chopping board" that sandwiches the magnets.
  • The magnets are held in place with the pressure action of the shaft bolts and four other smaller stainless steel machine screws are arranged to help keep the magnets in place.
  • The shaft was a 5/8" stainless threaded rod.
  • The shaft was affixed to the rotor with two stainless nuts and a stainless washer on each side.
  • The shaft was machined at each end to fit the bearings that I had lying around.
  • The mass of the rotor is 967 grams.
  • The Diameter is 12.5 cm.
  • The bearings were from the pickup arms of a few identical old hard drives that I had come across. There were two bearings in each arm and I used 3 bearings on each end of the shaft.

Mini high-speed low friction bearing from hard drive arm assembley.	Magnets with tape wrapped around to help with the compression fit of the magnest. This rotor is only good to about 3,000 rpm as the magnets start to "creep" then and hit the stators. Yikes!
Top view.	I counter-sunk the machine screws into the top for a nice smooth look. The bottom hower has the bolts and nuts stiching up.

• Switch Details
  
  
  • 200 watt reed switch. - See Mk 2.0

Mk 3.0

Oct. 2002

Test Results, Discoveries & Conclusions

• Test Results
  
  
  • Coil combined resistance was 6.8 ohms.
  • Duty cycle is about ~ 45% timed off rotor magnets.
  • The current draw on 12 Volts was ~ 600 ma.
  • The rpm ~1900 .
  • Measured power draw - to follow.
  • Calculated max power draw - to follow.
  • Runs on 12 Volts only.
  • There was more torque (loading capability) that was noticed right away.
  • There was good torque at lower rpm.

• Discoveries
  
  
  • Because I am switching through a big reed switch, I can see the beautiful violet plasma that forms during switch opening is now being quenched due to the fact that it is re-directed to another cap and then to a load.
  • As soon as the recapture diode is hooked up the rpm's increase about a hundred or so and the current drops off a little bit but could not get an accurate readings as all I had to measure current was a digital multi-meter and they do not work as good for tis application as well as analog meters.
  • Output of recapture circuit was highest during run-up or initial current draw, and then stabilized to about 7 Volts with a 25 ohm VCR-motor on it as a load. I tried a nice 45 omh test light and it was brighter than just off the 12 Volt battery. It got very hot too.
  • It used very little energy - approx 7.2 watts (12V x ~600ma). About the same as Mk 2.0 at 24 V.
  • Fairly high rpm about 2000.
  • Moderate magnetic coupling between non-powered stator core and rotor magnets.
  • The switch will not wear now due to the steering diode that was used. This energy is re-directed to another cap for re-use and is considered part of the output of these motors when it is used to power an external load. ie. it is subtracted from the measured watts in.

• Conclusions
  
  
  • The plasma must be quenched and this energy directed to a cap, battery, or some other load. Do not put a load on that is over 1/2 the current draw of the motor. This will fuse the switch.
  • The two new sators gave considerably more torque. I still want to try increasing the number of stators.
  • The 6.8 ohm series coil resistance gives almost a max amp surge to the switch of about 1.78 amps... this may be a bit to high for my reed switch as can be seen at lower rpm at sartup. If I could keep the current down to about an amp would be best for the switch I figure.
  • The back induction currents charge up a second cap which in turn has a small VCR- motor as the load on it. When the VCR-motor is mechanically loaded, the current rises on the input to the pulse motor. I feel that it is best not to load both at the same time.
  • A small mechanical resistance could be placed on the rotor without significant current draw.
  • Use a good big and accurate analog amp meter for measuring current draw.
  • A cap can be used in parallel from the supply battery as well to smooth out the pulses.
  • Using two(or more) coils does decrease current draw and lower rpm, at the same time it does give more torque which is needed for a motor to do work.

CAUTION: The information here is for educational purposes only. Any attempt at replication is done at full liability of the one replicating it. These motors can develop high rpm and high voltage depending on how they are designed. Build and operate at you own risk!

email me: motorlab@shaw.ca

For the copy-right/claim© 2001-3 by: Ian Coke-Richards and The MintakaFulcrum and may be freely distributed with due respect. Not for commercial purposes without permission and licence from the author. All commercial uses are subject to the terms of the user licence.