Pulse Motors- Your building them wrong.

[Nali2001]

Hi Brad, is there a recommended magnet diameter? I have 20mm and 10mm laying around. Do you tend to keep the diameter of the core of the electromagnet the same diameter as the magnet? What core material do you use. Normal silicon steel lamination should be fine right? Thanks!

[Thaelin]

Nali:
    Brad did mention to keep magnet 90% of a soft iron core. I have 1/2" mags and will use a 9/16" soft bolt with the head cut off.
All:
     Have most of the info needed but still have not seen if and when the coil should be shut off for the best results. Still trying to see how the rotor escapes the magnet. Does the two north facing fields make a dead spot?
thay

[tinman]

author=Thaelin link=topic=19546.msg582185#msg582185 date=1694467679

[/quote]

but still have not seen if and when the coil should be shut off for the best results.

That was clearly shown and explained in this video, which is why it is important to carry out this test.
There is no way i can tell you when the coil should be turned on or shut off on each individual motor without seeing the torque curve for that motor.  https://www.youtube.com/watch?v=QwbP4b4tlFU

Still trying to see how the rotor escapes the magnet.

Also clearly explained in the video, where the attraction force was removed from the pull force test by zeroing out the scales, so as to account for the very same force required for the torque plate to leave the gate.

Does the two north facing fields make a dead spot?

No, there is no 2 facing north fields when the torque plate is leaving the gate, as the coil was switched off long before that.

[tinman]

Hi Brad, is there a recommended magnet diameter? I have 20mm and 10mm laying around. Do you tend to keep the diameter of the core of the electromagnet the same diameter as the magnet? What core material do you use. Normal silicon steel lamination should be fine right? Thanks!

I would start with the 10mm magnets first.
The core of the electromagnets should be some 10-20% larger in diameter.

[tinman]

Hi Brad just wanted to run this by you first:

Turns out that it is a bit hard to find a steel rotor 20cm+
I do have a 30x40x 1cm thick plate I can machine to a 30cm circle, but it is aluminum. I can add some steel mass to the center to enhance the weight if needed. So is aluminum ok by you or do you have a theory that is needs to be steel?

Steel helps carry the magnetic fields, so as the torque plates do not become saturated.