On Aug 23, 2009, at 3:51 PM, Harry Veeder wrote:
Six links to papers on ball bearing motors, but
none of them give you access to free papers. :-(
Thanks for posting all this!
Some appear to contradict Horace's finding concerning non-
ferromagnetic
materials.
Harry
The ball motor only in theory. Experiment trumps theory in my book.
Note statement: "Experiments have not confirmed ...". Note also the
comment "However, this torque is [theoretically] too small in
practice to keep a ball bearing motor running."
About the stainless rollers on rails, that sounds like a version of a
rail gun. There may not even be a need for a thermal expansion
argument for that one. The same applies to brass balls on rails
experiment. If the current supply to both rails is on the same end
of the rails then it is just a simple rail gun.
I'm glad to see the error in Gruenberg's work was found specifically.
-----------------------------
1.
The electromagnetic torque on axially symmetric
rotating metal cylinders and spheres
M. P. H. Weenink
1981
Abstract The torque is calculated on an electrically resistive
rotating
cylinder and sphere through which a current is fed by means of sliding
contacts. The torque on a rotating cylinder is proven to vanish
identically for arbitrary angular velocity. The torque on the
sphere is
shown to vanish up to second order in an expansion with the angular
velocity as the expansion parameter. The nonzero torque in first order
found by Gruenberg is shown to be due to an algebraic error.
http://www.springerlink.com/content/g816l5g714564034/
first page is free.
----------------------------
2.
The electrostatic torque on a rotating conducting sphere
M. J. C. M. van Doorn1
1983
Abstract The electrostatic torque on a rotating sphere through
which a
current is fed by means of two diametrically situated sliding contacts
is positive in the direction of rotation. However, this torque is too
small in practice to keep a ball bearing motor running.
http://www.springerlink.com/content/l5618xjmt127xq62/
[First page is free. There he says it works with ferromagnetic as well
non-ferromagnetic material?!. Refers to Weenink. See also Watson
below]
Note statement: "Experiments have not confirmed ...".
-----------------------
3.
Investigation of small motors operating under the Huber effect
Proc. SPIE, Vol. 4236, 306 (2001); doi:10.1117/12.418768
Online Publication Date: 20 May 2003
Conference Date: Wednesday 13 December 2000
ABSTRACT
Adam P. Lauterbach, Wen L. Soong, and Derek Abbott
Adelaide Univ. (Australia)
The Huber effect is an interesting and potential useful means for
creating extremely small and simple motors. It is based on the
observation that torque is produced when current is passed through a
rotating ball bearing. This paper reviews the alternative explanations
for its operation and describes the design, construction and
characterization of two prototype ball-bearing motors based on high
precision miniature ball bearings. A key limitation of earlier work
has
been difficulties in repeatability due to rapid wear of the motor.
This
was overcome by using a data acquisition system to record the dynamic
acceleration characteristics and hence predict acceleration torque
versus speed characteristics.
http://dx.doi.org/10.1117/12.418768
---------------------------
4.
Investigations into the roller electrical motor
D B Watson, G R Bellam, W Y V Leung and S P Nolan
Abstract. The roller electrical motor (REM) consists of non-magnetic
stainless steel cylinders rolling on parallel stainless steel rails of
the same diameter with an electrical current passing from rail to rail
through the rolling cylinders. The REM is found to be capable of
carrying heavy loads, the electrical driving force increasing as the
current and loading are raised. When the REM carries a 50 kg load the
driving force increases at the rate of 80 mN . At 30 A the REM is
capable of driving external frictional loads of 1.7 and 2.2 N while
carrying loads of 50 and 100 kg respectively. This paper describes the
characteristics of the REM and discusses the origin of the driving
force. A thermal expansion theory is developed to explain the
experimental results.
Print publication: Issue 6 (21 March 1999)
Received 20 October 1998
http://www.iop.org/EJ/abstract/0022-3727/32/6/021
--------------------------------
5.
Non-ferromagnetic linear ball-bearing motors
D B Watson and A M Watson
Abstract. The paper describes experiments on a metal ball rolled along
parallel metal rails. An electrical force is developed on the ball in
the direction of movement by passing current through it from one
rail to
the other. Contrary to the electromagnetic theory of the ball-bearing
motor, the electrical force on a brass ball is of the same order as
that
on a steel ball. The results are discussed in terms of a torque
exerted
in the contact region.
Print publication: Issue 3 (14 March 1996)
Received 7 February 1995, in final form 8 August 1995
http://www.iop.org/EJ/abstract/0022-3727/29/3/007
--------------------------------
6.
Study of electrical characteristics of the ball bearing motor
Moyssides, P.G. Hatzikonstantinou, P.
This paper appears in: Magnetics, IEEE Transactions on
Publication Date: Jul 1990
Abstract
The electrical characteristics of the ball bearing electric motor are
studied for applied steady currents ranging from 43.5 to 70.15 A.
It is
found that the ball bearing behaves like a motor when it starts
self-rotating meaning that the shaft and inner race of the pair of the
ball bearing system start rotating by themselves without the help
of any
external agent, but with a small efficiency at high currents. During
self-rotation the motor's counter electromotive force depends on the
angular velocity of the shaft and inner race. The ball bearing's
behavior at low currents is also explained when it is not self-
rotating,
(i.e. rotating with the help of a conventional motor). In the latter
case, the motor does not behave like a generator. A theory, based
on the
electromagnetic interactions developed within each ball, is
proposed to
explain the action of the ball bearing as a motor. These interactions
are caused by the ball's primary currents and magnetic fields and the
effects of the induced magnetic field from the current of the
motor's shaft
http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=54012
Best regards,
Horace Heffner
http://www.mtaonline.net/~hheffner/
