pulse motor - bedini motor

I build this Bedini /Pulse motor because I was dissatisfied with other build, too complicated or too less "adjustable" /playable according to the parts I've at hand.

The weel uses 4 neodymium magnets 5mmx3mm. All the magnets shoud have same polarity on the faces outside (i.e. all with south pole outside).
https://www.aliexpress.com/item/32949700971.html?spm=a2g0o.productlist.0.0.6dee1a61rw6wKK&s=p&ad_pvid=202004190323283128102692848720003632215_1&algo_pvid=2cceb888-b404-47d8-a2c4-f5dd20256d39&algo_expid=2cceb888-b404-47d8-a2c4-f5dd20256d39-0&btsid=0be3746c15872918087232946e6e63&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_

As a shaft I use a 70mm Stainless Steel Needle for Leather Sewing.
I bought mine on ali here: https://www.aliexpress.com/item/32960765733.html?spm=a2g0s.9042311.0.0.27424c4dvx8IZv

Insert the needle in the rotor from the eye and press it down gently until it stops at about 10mm from the point.

The gantry is made of two parts kept in place by a 3mm screw.
To keep the needle point in place, in the bottom part of the gantry use a 5mmx3mm or 5mmx2mm magnet.
On top there is space for a 12mmx2mm magnet or you can stack three 5mmx3mm keep them in place with glue or double sided tape. Dont'use here peforated magnets (like I did because I've around) they will cause the rotor to "wobble".

Adjust the height of the gantry to keep the spinning weel in verticalposition with only the point touchin the bottom and the eye "floating".
This gantry creates a magnetically suspension system very low friction.

As a pulse coil I've savaged an old 12V relay , broken it and took apart the coil from the iron core (about 360ohm resistance The higher voltages/impedance the better, so if you have at hand you can use 24, 48 relais).
The upper frame for the pulse coil needs to be adjusted accordind to your coil. You can skip printing mine and print only the bottom part . Then glue with double sided tape your coil at the same heigh of the magnets.

The electrical circuit is very simple (battery-coil-reed switch-on off switch all in series) I use a little reed switch, 2X14MM normally open.
The switch is kept in place by double side adesive tape. Keep it orizontal and align it with the rotos magnets center at about 15mm from the floor.

TIPS:

First, When circuit is set, find the right battery polarity (the one that "pushes" apart the magnets of rotor .). Put the coil about 3mm from the rotor magnet and switch on. If the magnet is pushed apart it's ok, otherwise reverse battery polarity.

Second, Find the right distance of the reed contact from the rotor (start from 5/7mm then reduce), You shoud ear a little "click" This is the right position to start.

Third. Find the right angle of the reed contact. To give the pulse at the right time, note that reed contact position is not squared in respect to the coil. The reed must "anticipate" the position of the magnet of about 20 deg. The position must be found by trial and error.

This motor dosen't self start so after switch on you have to spin it a bit.

To prolonge the life of the reed contact, rembember to put in parallel to the coil an inverted diode (i.e. with cathode connected to + terminal). This will cut voltage spikes created by backEMF .This is the energy that perpetual motion gurus try to recover : with their bless I've used here a white led that flashes nicely while cutting the spikes.

Motor needs one coil to start. If you use two coils, spinnig force is more symmetrical and you can reach higher Rpms.

My motor starts to ignite at about 2Volts so I put two 1,5 AA battery in series to keep it spinning

With little adjustment, my build reached about 500rpm.

ENJOY!

If you find it nice for, fell free to donate.
More DIY 3D printed parts and DIY circuits in my site: http://www.webalice.it/guaccio1/