A ball bearing motor

Current images of fusor efforts, components, etc. Try to continuously update from your name, a current photo using edit function. Title post with your name once only. Change image and text as needed. See first posting for details.
Post Reply
User avatar
Rich Feldman
Posts: 1138
Joined: Mon Dec 21, 2009 11:59 pm
Real name: Rich Feldman
Location: Santa Clara County, CA, USA

A ball bearing motor

Post by Rich Feldman » Fri Apr 20, 2018 11:46 pm

As a side effect of Tyler Meagher's motor & pump cleanup, I had a cleaned up motor armature, about the size we would find in a Dremel tool. viewtopic.php?f=10&t=12189#p79527 Thought it would make a nice-looking ball bearing motor.

That took longer than necessary, because of excess attention to distributing current around the bearings' outer races. Maybe 50 to 100 amperes.
Online accounts range from incredibly lame:
bbm1.JPG
bbm1.JPG (13.58 KiB) Viewed 1523 times
to probably good & practical:
bbm2.JPG
bbm2.JPG (21.59 KiB) Viewed 1523 times

My bearing OD of 0.866 inches (22 mm) made it unlikely to find round copper, brass, or aluminum parts with the right size hole, so I made some. First a piece of brass from a scrapped valve, bored out on the Sherline lathe. Press fits are touchy -- a thousandth or two makes the difference between too loose (no contact pressure) and too tight (reducing the diameter of pressed-in bearing race). Then a piece cut from a coupler for 3/4" copper pipe. Its ID is 0.875 + gap for solder; measured to be about 0.887. Both got soldered to 8 AWG feeder wires.
DSCN0274.JPG
Of course the copper sleeve is much too loose, with average radial clearance of more than 0.010 inches. Could have cut a longitudinal slot, at least 2 pi x 0.010" wide, and squeezed the sleeve down onto the bearing with a hose clamp. Instead I filled the gap with bits of 28 gauge copper wire.
bbm3.JPG
bbm3.JPG (15.44 KiB) Viewed 1523 times
When pressed onto bearing by hand, the wires crush slightly and the circle distorts slightly toward an octagon shape. The thin wires won't mind carrying 10 or even 20 amps each, across their diameters. :-)

Here it's out for a spin. Current and voltage measurements to follow.
DSCN0283.JPG
Mike echo oscar whisky! I repeat! Mike echo oscar whisky, how do you copy? Over.

User avatar
Richard Hull
Moderator
Posts: 11544
Joined: Fri Jun 15, 2001 1:44 pm
Real name: Richard Hull

Re: A ball bearing motor

Post by Richard Hull » Mon Apr 23, 2018 4:34 am

I made this "Marinov" Ball bearing motor back in 1994 and displayed it at one of the old Telsthons before they became the HEAS conferences.

Typically runs at about 2.5 volts @ 50 amps just and aluminum shaft in two brass pillow blocks I milled out and inset ball bearings. Runs fine on AC or DC and can spin in any direction you choose even regardless of DC polarity, if running on DC. It just doesn't care what you feed it beyond a gang o' amps.

Richard Hull
Attachments
marinov1.JPG
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
Retired now...Doing only what I want and not what I should...every day is a saturday.

Post Reply