How to Build Magneto-Magnetizer

40 Pages·01.496 MB·English

by  David J. Gingery

WARNING:
There are generally recognized hazards in every pursuit of
machinery operation, construction and repair. And in this project
you will be exposed to the dangers of electricity as well. There
is a possibility for fatal electrical shock, fire or other injury
and property damage when working with electrical current available
at ordinary household outlets. If you are not knowledgeable and
skilled in working with electricity you should find professional
help for that portion of this project. And you should check local
electrical codes and insurance underwriters rules before plugging
in a home built electrical device. Bear in mind that the author is
not a scientist or engineer and that no amount of professional
engineering has been applied. This book is intended to describe
the author's experience and discoveries for the benefit of others
interested in a similar pursuit. While the intention is to present
a safe project, no attempt has been made to discover and reveal all
hazards. You are entirely responsible for your own safety and the
safety of others who might come in contact with equipment you build
a n d o p e r a t e.
FOREWORD
This is another offering in a series of HOW-TO manuals intended to
provide basic information to individuals working at home. Most of
the information gathered for these projects is taken from out-of-
print material and may be considered obsolete in the modern world
of high technology. However, our pursuits in the home shop are
usually for pleasure rather than profit. And the efficiency and
economy that might be possible with modern methods is not a vital
consideration in a non-commercial project. We can be content to
have achieved our end by simple means since modern methods may very
well be beyond us technically, even if we could justify the cost.
And it may even add to the personal satisfaction if we are able to
achieve by simple means that which others can only stand in awe of.
It is a challenge and a pleasant adventure to research these
projects, to build them and test them and finally to publish them.
And it is never done single-handed. So here I offer thanks to the
many friends and readers who offer suggestions and encouragement.
And special thanks to two major contributors to this project:
Don Cokley, who worked dilligently on the research
and every detail in building the prototypes.
AND
Al Shepard, who did some of the machine work.
CONTENTS
MAGNETO DEVICES 2
MAGNETISM 3
INDUCTION 4
MAGNETO TESTING 5
OTHER MAGNETO DESIGNS 7
BASIC REQUIREMENTS 8
BUILDING THE MAGNETIZER 11
MATERIAL LIST 11
ASSEMBLE THE BASE 12
ASSEMBLE THE CORE . . 17
COIL DESIGN 17
THE COIL FORMS 18
THE COIL WINDER 22
WINDING THE COILS 24
INSTALL THE COILS 26
THE POWER SUPPLY 30
TESTING THE POWER SUPPLY 32
TESTING THE MAGNET 32
OPERATING THE MAGNETIZER 33
SPECIAL POLE SHAPES 35
ILLUSTRATIONS
THE BASE 13
CORE LAYOUT 14
CORE ASSEMBLY 15
CORE AND BASE ASSEMBLY 16
MAKING THE COIL TUBE 19
NOTCHING COIL TUBE 20
ASSEMBLE COIL FORM 20
COIL WINDER SIDE LAYOUT 21
COIL WINDER ASSEMBLY 21
COIL WINDER SPINDLE 22
COIL WINDER DISCS AND HUBS 23
COIL WINDER IN USE 25
FINISHING THE COILS 25
INSTALLING THE COILS 26
INSTALL THE CHASSIS BOX 26
ELECTRICAL COMPONENTS 28
SCHEMATIC DIAGRAM 28
PICTORIAL DIAGRAM 29
SPECIAL POLE SHAPES 35
INTRODUCTION
job, and the best key to
There are few mechanisms more restoring a non-functioning
fascinating than old internal mechanism to normal operation
combustion engines. And is to fully understand what is
equally fascinating are the normal.
ignition systems that enabled
them to run. While countless It would require a large book
thousands of the old engines indeed to describe and fully
have been broken up and melted illustrate the various types of
down to be resurrected as more magnetos. But I will have to
modern machinery, it would seem leave that book for others to
that they might easily have run publish. The main intent here
forever had it not been for is to detail construction of
some mysterious failure in the the equipment for restoring the
ignition or fuel system. In vitality of the magnets. But a
fact today many of the relics few broad and general tips will
are being rescued from the be offered to guide those who
scrap heap, and determined are completely in the dark
people are restoring them to about magneto ignition devices.
running condition.
In keeping with a very wise
Fuel systems are generally easy adage: "IF IT AIN'T BROKE DON'T
to troubleshoot and restore by FIX IT", I urge you to develop
simple cleaning and perhaps a careful series of diagnostic
making a small part or two. steps before diving into the
Battery ignition systems, too, inner workings of the magneto.
are straight forward, and any
able mechanic can determine by In all of this discussion it is
simple tests whether the coil assumed that you are working
and condenser are good and if with old engine magnetos that
the points make and break will seem rather complex. And
properly. But if the engine is especially if they are equipped
equipped with a magneto the with "IMPULSE MECHANISMS" that
challenge becomes greater and are designed to accelerate the
it will be necessary to delve a speed of the magneto rotor to
little deeper. gain voltage. But they do not
differ in principle with modern
It is the purpose of this book magnetos as found on the usual
to reveal a few clues to aid in engines of lawn mowers, garden
solving the mystery of those tillers, etc.. However while
very cunning mechanisms. And you can buy just about any
since there is much more to a required part for the modern
magneto than its magnets we machine it is a very different
will spend a little bit of time matter with old equipment. And
discussing some of its other so also is it difficult to find
elements. specifications and service data
for old machines. So then it
Like all mechanisms, a magneto becomes necessary to be very
is designed to do a specific cautious and observant so that
any part removed will not be thermistors, varistors and
damaged and that it will be other such truck onto a multi-
reinstalled properly without layered circuit board and fuse
the aid of a repair manual. the whole thing into a glob of
plastic with wires sticking out
Even though the magnetizer is at various points. Then they
the main offering in this book conceal its true identity with
it must be stressed that merely code numbers and letters that
recharging the magnets will would stump agent 007, and then
seldom restore a magneto to proceed to design a replacement
efficient operation. However that will obsolete the newest
magnets do lose their magnetism thing developed even before it
for various reasons and in that hits the market. The things
event it will be absolutely are designed to self-destruct
necessary to re-magnetize them. if you apply a test meter to
try and figure out if they are
There is nothing at all new or any good. If you break them
original in the design of the open there will probably be
magnetizing device detailed nothing recognizable inside.
later in the book. In fact a And if you brought one to the
very similar device was most feet of the Oracle at Delphi in
likely used when your magneto the hope of learning something
was originally manufactured. about it he would probably
The only significant difference shrug his shoulders and advise
would be the modern solid-state you to devote your time to
power supply. something more worthwhile. But
you can understand and repair
Since the pole pieces of the engine magnetos.
magnetizer are adjustable the
device can be adapted to nearly Magneto ignition systems are
any ordinary magneto or magnet . actually not greatly different
Further, specially shaped poles from battery systems so basic
can be installed and adjusted troubleshooting is much the
to adapt to many other designs same. It.would always be nice
including flywheel magnets and to have some sort of instrument
bar magnets. And of course it that you could hook up that
can be adapted for experimental would tell you instantly where
use or for production of many the trouble is and what to
permanent magnets for a wide repair or replace. Such are
variety of purposes. modern computerized systems.
Or at least that is the claim
MAGNETO DEVICES of those who build them and
foist them upon us. A computer
A magneto is not nearly as would prove of little value in
mysterious as some of the diagnosing magneto troubles.
"BLACK BOXES" found on modern But everything you need to know
machinery and appliances. The can be quickly learned by-
fiends who design this stuff simple tests. And when these
will put coils, capacitors, simple tests indicate that all
transistors, diodes, IC's, should function if only the
magnets are good you will have mysterious of the physical
the necessary equipment to phenomenon. While its actions
recharge the magnets if you can be compared with those of
build the simple recharger electrical currents there are
described later. But bear in distinct differences that have
mind that magnet failure is not challenged great minds for
the most common or likely cause centuries.
of magneto failure. And, more
important, magnets should not The first natural magnets are
be casually removed or ever said to have been discovered in
carelessly handled. In fact Magnesia, a small country in
you can lose a significant Asia Minor, around 600 B.C.,
amount of magnetic strength by Thus they came to be called
simply removing the magnets "Magnets". Knowing the origin
improperly. And reinstalling and date of discovery helps not
them backwards can get you into in the least except that we can
some very serious trouble. impress people who did not know
Dropping a magnet or striking that already. And knowing the
it with a hammer can also origin of the name frees the
effect its strength. And mind to look for more valuable
excessive heating, as with a information since we don't have
torch, can completely to wonder why it's called
demagnetize the magnets. The magnetism. A great deal has
been learned about magnetism in
discussion on basic trouble-
the past centuries but much
shooting and repairs will be
remains to be discovered.
general and brief but you will
get full details on building
and using the magnetizer a bit It is theorized that molecules
later. The best rule to follow are aligned within the body of
is to always leave the magnets magnetized materials so that
undisturbed until you have the attracting and repulsing
thoroughly considered every forces of the electrons are
other possible cause for concentrated and polarized.
failure.- Nothing can be gained from a
discussion of theory except
A magneto is essentially a that we might finally agree
generator used in conjunction that one expression of theory
with inductance and capacitance seems more plausible than
to deliver an electrical spark others. But while little is
at the required instant to known or understood about what
cause ignition in the engine magnetism is and how it works,
cylinder. As the name implies, a great deal is known about its
its source of energy is its effects. That knowledge is
magnet or magnets so that is useful in a study of magnetos.
the proper place to begin the
discussion. Natural magnets are a
crystalline form of iron oxide
MAGNETISM that has come to be called
"Magnetite". Very rich ore
Magnetism is among the most that yields high quality iron.
Early sailors discovered that magnetism is that unlike poles
an elongated piece of it hung attract and like poles repel.
from a cord or floating on a And the same law applies in
block of wood in a pan of water electricity and electronics.
would always orient itself with Understanding these laws is
one end pointing north and the vital to an understanding of
other south and thus the first induction.
magnetic compass was invented.
They called it a "Lodestone", INDUCTION
which means "Leading Stone".
Just as an electrical current
Modern manufactured magnets are is induced when a conductor
many times stronger than cuts a magnetic field, so is a
natural magnets and they are magnetic field induced each
made in an infinite variety of time an electrical current
shapes and sizes. Many other passes through a conductor.
uses have since been found for Generators and transformers
magnets and a large proportion function on these very basic
are used in electrical and principles. And a magneto is
electronic devices. really a generator to supply a
transformer, or it incorporates
Of particular interest to us is a transformer in its design.
the fact that when a magnetic Actually the magneto is more
field is cut by a conductor an precisely an alternator that
electrical current is induced. produces an alternating current
You can prove that yourself by at low voltage to be built up
winding a small coil of about to a voltage high enough to
10 turns of insulated wire and discharge a spark. It is the
connecting its ends to a very rapidly changing magnetic field
sensitive milliamp meter. Then that induces the current. And
pass a strong permanent magnet the greater the number of turns
back and forth over the coil or in the coil the higher the
through its center and watch voltage. So also, the faster
the meter needle deflect. That the magneto spins, the higher
is the phenomenon of INDUCTION, the voltage.
and what you have done is to
fashion a simple generator. A typical magneto has a set of
field magnets that charge the
And we are also interested in pole sections. The rotor is
the "POLARITY" of the magnet. wound with a coil of wire that
I.E., one pole of a magnet will represents the primary of a
align with the magnetic north transformer. As it rotates
pole of the earth and the other between the magnetized pole
aligns with the south pole of pieces an alternating current
the earth. The magnetic is induced. At precisely the
polarity of the magnet has a right moment the contact points
direct relationship to the in the primary circuit open,
electrical polarity of the which causes the magnetic field
current it induces. (Positive of the armature to collapse
or negative) A physical law of rapidly, inducing the necessary
high voltage in the secondary it for replacement or to modify
winding to deliver the spark. the design so that an external
condenser can be installed.
Given fully charged magnets,
sound coils and condenser and The logical first step is to
properly functioning contact clean the points and make sure
points, a magneto will deliver that they are opening and
a hot, snappy blue spark of closing properly and that there
sufficient length to jump the are no electrical shorts or
spark plug gap and fire the opens. A simple ohm meter is a
engine. practical tool for these tests.
Then crank the engine or spin
MAGNETO TESTING the magneto manually to see if
it will deliver a spark.
As with any electrical ignition
system the logical first test You can test a condenser with
is to determine whether a spark the ohm meter if you isolate it
of sufficient strength is being from the rest of the circuit.
delivered. It is a simple The meter needle should jump
matter to remove the spark perceptibly and return to zero
plug, rest it on the cylinder when the test prods are touched
head and crank the engine. If to the condenser terminals.
you see a bright, blue spark Then reverse the prods on the
and hear it snap it can be terminals and the needle should
assumed that the magneto is again jump and return to zero.
functioning well. It remains If the ohm meter needle does
only to assure that timing is not jump when connected in
correct and you can look to either polarity an open
other causes for failure to condenser is indicated and it
start. If, on the other hand, must be replaced. If the
the spark is dim orange and needle does not return to zero
barely audible, if at all, you in both directions it is an
will be justified in looking indication of a shorted or
more deeply into the ignition leaking condenser, which must
system. Naturally a weak or be replaced.
non-existent spark indicates a
failure in the magneto.
It has been a common practice
to test a magneto by applying
By far the most common problem battery voltage to the contact
with magnetos is a faulty points to test the coil and the
condenser or dirty contact condenser. What the test might
points. Sometimes it is a prove is that the points, coils
simple matter to install a and condenser are functioning
replacement condenser that is and that the failure is in the
known to be good and the generating or delivery system.
magneto is restored to perfect In fact failing magneto systems
operation. But some older are sometimes converted to
magnetos have the condenser battery systems in this way.
built into the rotor and it can But while it may enable the
be a major job to disassemble timing mechanism to deliver a
spark and get the engine magnets if at all possible. If
running it can also demagnetize the magnets must be removed to
the magnets. The particular complete disassembly they must
design of the magneto will be carefully marked to be
determine whether such a test returned to their original
or emergency measure can be polarity. The magnets are also
safely used. So bear in mind effected by shock so you must
that if you send an electrical not pound on them or drop them.
current through a coil that is
part of a magnetic circuit you Some magnetos have both the
may cause a counter magnetic primary and secondary windings
field that can damage the on the rotor, while others have
magnets. only the primary winding on the
rotor with the secondary on a
Some magnetos use brushes to separate laminated core. Still
collect the current and these others will have both primary
can fail. It is also possible and secondary on a separate
for carbon from the wearing core and the rotor will provide
brushes to collect and provide the magnetic field.
a short circuit to ground,
causing the magneto to fail. Coils fail through open or
short circuited windings and
Bearings can fail, causing the they can be tested with the ohm
rotor to drag on the pole meter.
pieces and that will cause
magneto failure. Magnetos are More difficult and uncertain to
usually cunningly made and determine is whether or not the
disassembling can be tricky, so secondary coil insulation is
proceed slowly and cautiously. leaking. Lacking specialized
It may become necessary to equipment a leaking coil is
completely disassemble a diagnosed only by elimination.
magneto to clean dirt, carbon That means when you have made
and oil, or to replace bearings certain that everything else is
or other parts. That will OK the problem can only be a
require careful study, plenty leaking coil.
of light and a clean bench top.
In no case should you remove
It is rarely possible to
the magnets without first
restore a leaking coil by
putting a "Keeper" across their
baking it for a couple hours at
poles. A keeper is a bar of
225 degrees F. to drive out the
iron or steel used to bridge
moisture. But if you are
the gap between the poles of
certain the coil is leaking
the magnet so that the magnetic
nothing is lost by trying. You
circuit will remain intact. A
are going to need permission
very substantial amount of
from the lady of the house to
magnetism can be lost in only a
do that , and you are probably
moment so always be prepared to
going to get into big trouble
recharge your magnets if you
anyway if you make some smoke
handle them improperly. And
or smell. If baking out the
you should avoid removing the
moisture restores the coil you
should soak it in thin varnish the condition of the magnets
to seal it. and how to test them.
When testing coils with the ohm The only practical magneto
meter make certain that they magnet test I've ever known of
are isolated so that you don't is that "A good magnet will
get a false reading from a lift 20 pounds of iron.". It
faulty condenser or shorting or is a simple matter to attach a
dirty points. Also check for plate of mild steel to a spring
"carbon tracking", which is a scale and observe the scale
tiny high resistance path to reading then the magnet pulls
ground due to a dirt or carbon free of the plate. Of course
filled crack in insulation. there are modern devices that
will measure field strength and
Some magnetos have a "Safety evaluate magnets in technical
Gap", which is designed to terms. But by far the most
discharge the spark to ground common practice in commercial
safely if the high tension magnet testing continues to be
wiring or spark plug fails. comparing the "pull" or field
The idea is that voltage could strength in some sort of
become high enough to pierce mechanical testing fixture.
insulation in the secondary Without very expensive and
winding if it does not find a sophisticated equipment magnet
safe path to ground through the testing for most of us will
spark plug. The safety gap remain a matter of acquired
will be somewhat wider than the judgement. It will generally
normal spark plug gap so that be impractical to remove the
it won't interfere with normal magnets to determine if they
ignition. But it will be close will lift 20 pounds. But after
enough so that if the spark handling a number of normally
plug gap widens too much or the functioning magnetos you will
spark plug wire is removed the learn to judge the amount of
spark will jump the safety gap magnetic "drag" you feel while
and preserve the insulation of rotating by hand. Of course
the secondary coil. It is the impulse mechanism can
possible for the safety gap to interfere with manual turning
become shorted so that spark so partial disassembly will be
will not be delivered even required for some testing.
though the magneto actually is
functioning. And if you remove OTHER MAGNETO DESIGNS
the spark plug wire and crank
the engine to test for spark The types of magnetos we have
you may not see a spark at the discussed up to this point are
wire because it is discharging all "High Tension" magnetos
at the safety gap out of view. that deliver a high voltage
By now it must be apparent that spark through a rotating
magneto troubleshooting is very mechanism. There are also
little different than trouble- reciprocating magnetos or
shooting battery systems. The oscillating magnetos that
only other element of doubt is accomplish the same thing by