The source and distributor of current is what a magneto can be called. Appropriate types of current are used inside carburetor engines to ignite the combustible mixture. Thanks in fact this mechanism mechanical energy is converted into electrical energy. A tractor magneto often comes complete with an internal combustion engine.
The device diagram will have the following description:
- Opposite the magnetic core shoes are the pole pieces from the rotor.
- The transformer core causes the power lines from the magnets to begin to close.
- When the magnet is in a 90-degree position during rotation, the main element becomes the gap between the tips and shoes.
- It is imperative that the lines of the magnet intersect with the turns of the windings of the transformer. Due to this, the electromotive force acquires induction. Ignition is also used in the processes.
Magneto distributes current
The EMF acts on the device in such a way that when closed contacts are used, a magnetic flux appears at the transformer core. As a result of opening the circuit, the current disappears from its primary type. Because of this, the magnetic field is sharply reduced.
Induction of EMF up to 25,000 Volts occurs when using a secondary winding. Self-induction of EMF up to 300 V will appear only if you open the contacts from the primary winding. The primary type circuit produces a self-inductive tone, which causes the magnetic current to disappear more slowly. Such situations are characterized by a decrease in the EMF for the secondary circuit.
Parts often begin to burn when sparks appear at the contacts. Connecting a capacitor to the structure is carried out in order to avoid such consequences. Then there is no spark between the contacts in the magneto, which is described above.
The rotor can be easily rotated to a 90 degree position. Afterwards the primary circuit is opened with a breaker. This moment is called the magneto outline.
Device diagram
The location of the transformer part inside the magneto on the tractor is characteristic. The part is pressed onto the shaft, helping to create a high voltage current. Another important part of the design is the rotor, which constantly performs the function of a permanent magnet rotating on two bearings. The cam is attached to the front of the rotor shaft. On the back there is a so-called leash. How each part works is easy to understand.
When the magneto device is mounted on the engine, the wire is supposed to fit into the groove of the gear. The case is closed with a corresponding cover, which is used as a base for installing contacts from the breaker and terminals at the transformer windings. The breaker itself is also closed with an easily removable lid.
The primary winding must be connected to a moving contact that is insulated from the housing. The other end is connected to the contact, which remains motionless. The secondary winding must also be connected to the secondary winding at one of the ends. The spark plug works on a central electrode that connects to the other end. The side electrode of the spark plug is also connected to the magneto and starter housing.
Magneto setting
Each device has its own operating characteristics. They must be taken into account when setting up the mechanism.
For walk-behind tractors
When walk-behind tractors must operate uninterruptedly, the use of tractor magnetos will become optimal solution. M-151 or M-137A are acceptable device options that can be installed in any conditions. Installation is carried out on the engine using flange connections. It is enough to use three small pins.
M-151 is a two-disc variety that contains the following components:
- Start accelerator.
- Housing supplied with distributor.
- Breaker plate.
- Transformer part.
- Roof.
- The part with the rotor.
- Frame.
Sufficient speed is transmitted to the rotor thanks to the starting accelerator. For this purpose, separate impulses are used. Starting and constantly rotating the engine results in a strong spark.
Such a device allows us to solve the problem associated with the fragility of the battery part with which walk-behind tractors are supplied. If you buy special adapters in advance, it will be easier to turn your idea into reality. The design is created independently or ordered by contacting specialized workshops. The adapter is created using autogen. Steel sheets with a diameter of up to 230 mm are used. The principle of operation does not change because of this.
In the case of MTZ tractors
M 124-B1 is a type of device that usually complements tractors. The magneto rotates to the right, 27 degrees being the angle at which the ignition is advanced. The PD-10 starter coupling half sets the mechanism in motion.
A two-contact magneto, along with any variety, includes the following components:
- Transformer.
- Intermittent.
- Rotary.
The rotor part is involved in the creation of alternating current. The energy is then sent to a transformer to raise the voltage to its maximum level. One of the last stages is the transfer of current to the breaker. Because of this, strength decreases. There is a decrease magnetic current. A spark discharge is created in the electrodes of the spark plugs, and the hot mixture is supplied with appropriate ignition. It's easy to figure out how to adjust the device.
Diagnostics of technical condition
Diagnostics is carried out by performing the following procedure:
- The first stage is connecting the high-voltage cable to the voltage terminal.
- The second end of the cable is constantly held at a distance of about 0.5-0.7 centimeters from the device body.
- Maintaining position near the wire. Next comes a sharp turn of the rotor in the direction of rotation. The spark should jump as a result of this movement; if everything is in order, the magneto is adjusted correctly. If there is no spark or is too weak, there is a high probability that the installation requires a malfunction check. If necessary, adjustments are made.
Common malfunctions and their repairs
Here are just a few of the most common problems magneto owners may encounter:
- Failures during sparking. There are several reasons for this situation and ways to resolve the problem. TO possible problems include: contacts burn, oxidize; the gap adjustment is violated; the lever cushion at the breaker is worn out; The capacitor element was broken. If an element fails, it is completely replaced. When the problem is in the gaps, they undergo additional adjustment. Contacts are also changed or completely cleaned. How to set up the magneto is described further.
- Complete lack of spark. This often happens because the transformer wiring has broken, there has been a short to ground, or the insulating layer that supplies the high-voltage cable has broken through. If problems arise with the transformer, the unit must be replaced. You can eliminate the short circuit itself or change the cable when an insulation breakdown occurs.
- A broken capacitor is the most likely cause of a spark that is too weak. In this case, the part must also be replaced.
Candle and armored wire
The armored wire itself also requires additional testing. This concerns two elements:
- Fastening in the mounting socket.
- Base for a candle.
Complete stripping of the wire from each end by 2 millimeters is an excellent reason for inspection and repair. You can check using a different armor wire instead of the one installed initially.
If the spark plug is faulty, it is also replaced; the part is not repaired.
Part diagram
Capacitor
It is needed so that the contacts do not burn too much. It consists of two plates and insulation, the role of which is usually played by foil. Everything is rolled into one roll and placed inside the case. In some cases, if the housing is damaged, the capacitors can be adjusted using sandpaper. It is important that the structural parts do not overheat during operation. Adjusting the magneto after this will not help.
About breaker contacts
If they become faulty, the first recommendation is to clean the surface using a special flat abrasive plate. The work can be done without problems with a flat file with a fine notch. Cleaning with sandpaper or glass paper will not give the desired result. The contacts wear out too quickly, and in this case a flat surface cannot be obtained.
From time to time, contacts also require cleaning from plaque and adjusting the gaps between parts. The main thing is not to lose a single part during disassembly. The contact spring is subject to malfunction or straightened in the opposite direction.
Coil or transformer
It is easy to repair the tractor magneto for such parts. This same part of the engine rarely fails; it can operate uninterruptedly for a long time. If the part has become unusable, then it must be replaced with exactly the same, but working model.
Rotor
The main thing is that it does not crumble or break during operation. From time to time the rotor can become demagnetized. If the part really turns out to be damaged, then it is replaced. The main thing is not to forget to remove metal fragments, sometimes they remain inside the magneto housing. Bearings require separate inspection and lubrication.
Conclusion
Every mechanism malfunctions from time to time. But nothing bad will happen if you deal with the problem in time. The first steps are to remove the cover, check for damaged wires and defective insulation. Housing contamination and oiliness are popular causes of malfunctions. It is enough to spend some time to sort out the problems.
The engine ignition system includes a flywheel magneto, a high voltage wire, a spark plug and an ignition switch. The contact magneto (Fig. 4.6, a) consists of permanent magnets fixed in the flywheel rim and a base on which the ignition coils, breaker and capacitor are mounted
Design and operation
Magneto is a specialized alternating current generator excited by a rotating permanent magnet (magnetic rotor or armature).
An automobile magneto has low and high voltage windings. Parallel to winding low voltage(LV) the breaker contacts and the capacitor are turned on (~0.1 µF); the leads of the high voltage winding (HV) are connected one to the housing, the other to the spark plug. All windings are wound on a yoke (core) and look like one large coil on a U-shaped core; between the poles of the core there is a longitudinally magnetized rotating magnet (telephone and mine-explosive (KPM) inductors are designed differently, but the principle of operation is the same). A low voltage winding can act as part of the high voltage winding, that is, an autotransformer design is possible, this allows you to reduce the number of turns of the high voltage winding.
Fob Price: US $3 - 4.5 Port: QINGDAO
Minimum Order Quantity: 500 Set/Sets
Supply Capacity: 80,000 Set/Sets per Month
Delivery time: 15days
Payment terms: L/C,T/T
User manual
1. Main parts of the chainsaw:
- holder (consists of a grabber, a pusher and a step)
- rattle (consists of a navel, a lever, a button, a puller, two screws, a gas tank and an oil tank)
- a saw (such a long flat saw sticks out in front, consists of a cloth and a chain put on it - not gold!!
- a system for ensuring the safety of the chainsaw operator in the event of a sudden rebound of the blade with the moving chain upwards and preventing injury to the chainsaw operator by the blade with the moving chain in the area of the head, back, or another chainsaw operator (there is such a tricky plastic grip above/in front of the sawmill)
2. Before you buzz
a) Pour two magic solutions into the saw.
The first solution is difficult to prepare and consists of the flammable toxic liquid “Gasoline AI-95” and the magical composition “Oil for two-stroke engines” mixed in a ratio of 40 to 1.
Measure with a pipette, beaker, test tube to the nearest drop. It is allowed to measure with corks, caps, glasses, glasses.
It is allowed to change the ratio from 30 to 1 to 50 to 1 +- 5 to 1
The resulting solution has an attractive color and smell.
The solution is necessary for rattling.
A distinctive feature of a correctly prepared solution is that the rattler will work like a magic word. If the rattler does not work, you should replace the magic word with a more magical one.
Outdoor! If the composition is taken internally, bite charcoal and smoke.
About 300 milliliters of the first solution is poured under the large neck of the chainsaw (near the holder).
The second solution is poured into a small neck (near the saw blade). This includes any oil, motor oil, transmission oil, nigrol, mineral water, synthetic and semi-, castor oil and, according to rumors, even waste oil.
Attention! Cold starting on thick oil should not be difficult.
The tank capacity is about 100 milliliters. The solution is necessary for the saw to work.
b) Check the correct condition of the saw blade.
The chain in the middle of the web, if you pull it, should move 4-5 mm. If more or less, the chain needs to be tightened.
This is done like this:
- in the suitcase there is a magic key (not gold)
- with one end of the key, loosen two nuts by 1-2 turns close to the blade, on the side opposite to the plugs
- the second side of the key turns a small screw next to the blade, perpendicular to the plane of the nuts
- clockwise - for tightening, counterclockwise - for loosening
- check the chain tension
- then again tighten the two large nuts with the first side of the key 
3. To buzz
a) pour both magical compositions into containers specially designated for them. do not let the ingredients mix!!
b) close special containers with special stoppers
c) cock the “safety system...” (press it firmly and sharply towards the saw, it will either press lightly or click - it’s triggered, which means... then pull it towards you with great force until a dull knock occurs - the trigger is cocked )
d) track the position of the button on the rattler (the button should be in the OFF state)
e) press the rubber navel next to the large plug several (5-6) times until magic liquid number 1 appears in it (in the navel).
f) pull the lever several (3-4) times at full speed to ensure that both liquids enter all the necessary tubes and slits
g) disperse those around you to a distance of at least 5 meters; you don’t have to drive away those who are especially annoying, but let them hold on to the saw
h) turn on the button!!! (turn to ON position)
i) place the chainsaw on the ground
j) make sure that the saw does not touch the ground - this is not a shovel, but
k) step on the stepping stone with your right foot
m) sharply pull 2-3 times with your right hand on the puller
n) the rattler will not turn on
o) say the magic word
n) kick the rattle
p) try to pull out the blue lever (choke) next to the pusher
c) suddenly it will help
t) although it never helps
y) but must
f) even, it seems, helped a couple of times
x) just in case, say the magic word
c) repeat operations e-k-l-m-m
h) in case of failure, repeat operations e-p-r-s-t
w) if, more than expected, the rattler starts working - say the magic word
y) an unheated rattler may not hold idle speed even with suction, so turn on the saw by pressing the trigger with the fingers of your right hand, after first pressing the safety lock on top with the palm of your right hand. The choke lever will automatically retract.
ATTENTION!!! A working saw is a terrible weapon!!! Do not give it to children, pregnant women, old people, the faint of heart or harsh Siberian lumberjacks!!
ъ) if all the above operations did not help, say the magic word
s) there is a trick that almost always works. Step on the step with your right foot, and at the same time press the pusher from below with the same foot (with your right foot), for which you first press the safety catch.
b) then pull the lever again
e) while constantly saying magic words
yu) the rattle will rattle
i) say the last magic word - you can fight
4. How to fight.
- when you press the button, the saw starts to work
- if the saw does not work when you press the button, then the “security system” has worked..
- in this case, turn off the rattler and arm the “security system” again..
- do not keep the saw idling for a long time (without biting) - this is harmful to it
- select a victim and carefully approach it. try not to scare off.
- it is forbidden to poke the victim with the end of the saw - the consequences can be sad - the canvas will fly up. if your hands are strong - in the face, if weak - in the back. You won’t even have time to say the magic word..
- the saw is inserted into the flesh of the victim with the underside of the blade, preferably closer to the middle of the blade
- can be from above, below, from the side
- in the case of a bottom-up cut, it is allowed to work with the upper side of the blade, but be extremely careful, do not push upward as hard as you can - the consequences are described above
- if during an attack the victim resists and pinches the cloth, try to prudently remove it from the trap and attack slightly from the side to widen the edges of the laceration
- if this fails and the blade is caught in the trap, the saw is blocked and it does not work - turn off the rattler and use available means (crowbars, axes, other operators) to try to expand the trap to remove the saw. do not pull the chainsaw out of the trap as hard as you can - it will hurt the victim
- when standing, stand to the left of it, so that the plane of the canvas passes by you, slightly to the right. just in case.
- fully filled tanks last for 30-40 minutes continuous operation rattlers or for 2-3 large victims
- it is not recommended to apply the saw to others - they may be offended
- it is recommended to work in closed shoes, because from under the sawdust a strong stream of sawdust hits the shoe. then you'll be tortured to get splinters out of your socks
5. To avoid buzzing
a) press the button to the OFF position
b) say the magic word
6. Return everything as it was
- try not to leave liquids in the tanks - they will leak out!
- put the chainsaw in the suitcase
- don’t lose the magic key
- put it in your suitcase too
- put the white and yellow bottle with the magic liquid there
- say the magic word
What is a magneto? Magneto operation
Magneto is a magnetoelectric alternating current generator that creates electrical discharges between the electrodes of the spark plug to ignite the working mixture in the cylinders of internal combustion engines. The operation of a magneto is based on the principle of electromagnetic induction.
The essence of induction is as follows: when a magnetic field is crossed by a closed conductor, an electric current arises in this conductor. When electric current passes through a conductor, a magnetic field is created around that conductor. Magnetic field is the space around a magnet in which magnetic lines of force (or magnetic flux) pass. 
These lines are located denser between the poles of the magnet. Alternating current can be excited in a conductor by rapidly changing the direction of the magnetic flux crossing it, for example, by turning a magnet around a wire coil.
The operation of a magneto with a rotating magnet is based on this principle. As the magnet rotates, the magnetic flux passing through the rod changes in magnitude and direction; As a result, an electric current arises in the winding, first in one direction and then in the other. The capacitor serves to improve the operation of the magneto. With a capacitor, a strong spark is formed, without it, a weak spark is formed. A capacitor is connected in parallel with the breaker contacts in order to reduce the sparking that occurs when the primary current is interrupted at the breaker contacts.
How does a magneto work?
When the magnet rotates, it excites a current in the primary winding, which is short-circuited by the contacts of the breaker. When the current in the primary circuit reaches its maximum, the breaker contacts open. Because of this, the primary current is instantly interrupted. The magnetic field that was created by the primary current also disappears. This sudden change in the magnetic field excites a high voltage current in the secondary circuit, which can break the gap between the electrodes of the corresponding spark plug. Further rotation of the magneto rotor causes the formation of a new spark, etc.
How to check the technical condition of the magneto?
During everyday operation, the functionality of the magneto can be checked as follows: connect the high-voltage wire to the high-voltage terminal and hold the other end of the wire at a distance of 5-7 mm from the magneto body, sharply turn the rotor in the direction of rotation. In this case, a correctly assembled and adjusted magneto, when the rotor is sharply turned, should give a spark that ensures breakdown of the above gap. If there is no spark or it is weak, check the serviceability of the magneto and wire insulation.
The engine ignition system includes a flywheel magneto, a high voltage wire, a spark plug and an ignition switch. The contact magneto (Fig. 4.6, a) consists of permanent magnets fixed in the flywheel rim and a base on which the ignition coils, breaker and capacitor are mounted. The ignition coil consists of a core 5 and the primary 4 and secondary 6 windings of the transformer wound on it. The breaker is connected in series with the primary winding of the ignition coil. The breaker contacts are opened by a cam on the crankshaft.
The base is installed in the left half of the crankcase on two studs with nuts. The spark plug consists of a body, side and center electrodes and an insulator. The ignition switch button is connected in series with the primary winding of the ignition coil. Magnets mounted on the flywheel create a magnetic field that crosses the ignition coil winding. When the contacts are closed, a low voltage current is induced in the primary winding; when they open, the magnetic field disappears, which causes the induction of electromotive force (EMF) in the secondary winding. An induced high voltage current flows to the spark plug and produces an electrical spark between the spark plug electrodes. The system is adjusted so that the spark appears at the moment when the piston does not reach the top dead center by 3...4 mm, or an angle of 28 ° along the circumference of the crankshaft, called the ignition timing. 
Non-contact electronic magnetos (Fig. 4.6, b) that do not have a mechanical contact breaker are installed on the motor of the MP-5 “Ural-2 Electron” and “Taiga-214-Electron” chain saws. The basic operating principle of a non-contact magneto is the same as a contact one. Current induction occurs using a high-voltage transformer, which is not fundamentally different from a contact magneto transformer.
The primary winding of the transformer is connected in series through the charging winding, a diode with a capacitor, and through a control winding with a thyristor. A thyristor passes electric current (opens) only when an electric potential of a certain value is applied to its control electrode. When the thyristor opens (when it becomes a conductor), the capacitor is discharged to ground through the primary circuit, a significant current pulse passes through the primary winding and a high voltage is induced in the secondary winding, creating an ignition spark on the spark plug. Thus, the control winding and thyristor perform the functions of a contactless breaker, which has no rubbing parts and mechanical wear.
To cool the engine, an impeller is mounted on the flywheel, closed with a snail-shaped cover, and a deflector is installed on the cylinder. Air is forced by a fan through the hole, scroll and deflector and cools the cylinder walls. The engine is also cooled by the working mixture entering the crankcase through the suction pipe.
Magneto ignition systems
In addition to the previously discussed battery ignition systems, a magneto ignition system is used to ignite the working mixture in the cylinders of starting carburetor engines of tractors. It consists of a magneto, spark plugs and high voltage wires. The design of magnetos of different brands is approximately the same. Magneto differ in size, location and configuration of individual parts.
Rice. 181. Diagram of the device and operation of a magneto
A magneto is an electromagnetic machine that generates low voltage current, converts it into high voltage current and distributes it to the spark plugs. Operating without an external source of electrical energy, the magneto combines a low-voltage alternator, a chopper, a capacitor and a high-voltage current transformer with a distributor (there is no current distributor in the magneto of a single-cylinder engine).
On tractor engines, the most widely used magneto is one with fixed windings and a rotating magnet. Magneto can be right-handed or left-handed, and based on the number of sparks per revolution of the rotor, they are divided into two-spark, four-spark and six-spark.
A magneto with a rotating magnet has a stationary U-shaped magnetic circuit (Fig. 181), between the pole pieces of which a bipolar or multi-pole magnet 1 rotates. In the upper part of the magnetic circuit there is a magnetic core with primary and secondary windings, which form a high-voltage current transformer. One of the ends of the primary winding is connected to the core, i.e., to ground, and the second to the fixed insulated terminal of the breaker 3. The secondary winding is connected at one end to the primary winding and through it to ground, and the other to the spark plug clamp.
The magnet is located in the magneto housing and is driven into rotation by the engine crankshaft. On one shaft. General information The breaker cam 3 is located with the magnet. A capacitor is connected parallel to the contacts of the starter. To crank the breaker, a capacitor is connected. During the starting period, the engine uses a starter that reduces sparking in the contacts, powered by the breaker battery and increasing the voltage of the battery. The starter is present in the secondary winding. fight electric motor direct current The primary winding and a rotating series excitation with a mechamagnet form a magneto generator with a low-voltage drive and a low-voltage alternating current device.
The starter has an excitation winding connected in series with the armature winding. Electric motors of this type develop maximum starting torque when braking the armature. This quality is necessary during the initial period of engine rotation during startup, when the moment of rotational resistance also has a maximum value. The armature windings and starter field windings have minimal resistance, since they have a short length and a large cross-section. When the starter is turned on or the armature is completely braked, the magnitude of the starting current for starters various types reaches 300-800 A. As the crankshaft speed increases, the torque, and with it the power developed by the starter, decreases. The starter power depends on the type and size of the engine and can reach kW.
In this article we will conduct review of magneto series M-151, which according to its parameters and technical specifications suitable for use on gasoline engines UD-15, UD-25, SK-6, SK-12, starting engines PD-15, electrical units AB-4, wheeled small-sized tractors T-012, etc.
Will also be provided detailed description of magneto M-151, principles of operation, as well as possible analogues.
Magneto M-151 two-contact, high voltage. Double spark, left rotation. Catalog numbers 1302.3728 , or 1302.372800. Manufacturer "KZATE", Samara.
It applies to both sources and distributors of current. Mainly used on carburetor engines, their main purpose is to ignite the combustible mixture.
In fact, magneto This is a kind of magnetoelectric mechanism that is capable of converting mechanical energy into electrical energy. It is often used on agricultural machinery and various walk-behind tractors.
Below we provide a diagram of the M-151 magneto device.
Consists of Magneto M-151 from a housing, a rotor, a cover, a transformer, a breaker plate, a casing with a distributor, as well as a starting accelerator.
Frame The unit itself is made of zinc alloy, the pole shoes are cast into it, and the outer ring of the ball bearing is pressed into the bore located inside the housing.
Push And remote terminals Ignition switches are mounted on the housing. The starting accelerator stop is also screwed into the housing, from the flange side.
The tasks of creating and changing the magnitude of the magnetic flux that passes through the pole pieces of the housing and the transformer core are performed by rotor. It includes a roller and a package of lamellas, which are pressed onto a magnet. The components are fastened together by pouring zinc alloy.
Rotor shaft provides a cone that is used to land on it launch accelerator.
Magneto cover also made of zinc alloy, provides a boring, which is used to press in the outer race of the ball bearing.
Also mounted in the cover is a breaker plate, a capacitor, a large gear gear with an axle, and a spark gap.
A drain hole is provided at the bottom of the cover.
To create high voltage when the magneto rotor rotates, it is used transformer, which in turn includes a core, primary and secondary windings (the core is assembled from individual electrical steel plates).
Breaker plate used to mount the contact post breaker lever.
Housing with distributor Magneto M-151 . casing– made of zinc alloy, it has two ventilation windows. Serves as a kind of shield for the high voltage distributor. Distributor made of press material, distributes high voltage to engine spark plugs.
Magneto M-151 is attached to the engine by a flange using three studs. The drive is carried out from the regulator gear using an intermediate clutch.
To date Magneto M-151 not released. Discontinued during Soviet times in 1985.
For changing this device magnetos of the M-137A series arrived, and later magnetos 1302.3728.
Our company offers to buy magneto M-151 at the current price, the products are in stock in the warehouse, so that there will be no interruptions in delivery, we will produce them in the shortest possible time!
We also offer such services as M-151 magneto repair, as well as units and other types.
If you correctly follow all the operating standards for the magneto, the unit will serve you faithfully for a very long time. In cases where a breakdown has already occurred and you yourself are unable to do anything, then order magneto repair possible from highly qualified specialists. To carry out high-quality repairs, you need specialized equipment, as well as original spare parts– we have it all!
Order magneto repair services You can always call the numbers listed on the website of our online store Agrobum- Zakupka.
Our staff will advise you! A quality guarantee is provided for both the product and repair services!
Back in the 19th century, the German inventor Bosch, who owned his own company, developed the first ignition system based on a magneto. Over time, shortcomings in the design were identified and improvements were made to the device. As a result, the Bosch company in 1890 was already fulfilling large orders for the production of ignition systems based on this principle. Orders came in in large quantities. In 1902, Bosch's student Honnold modernized this design and made it universal.
A magneto is a device used to convert the rotational energy of the rotor into electric current, namely, a high voltage discharge on the spark plugs in a gasoline internal combustion engine. Currently, this device is practically not used, but it can still be seen on old designs of automobile engines, or on tractor starting engines.
If we compare this device with a generator, the difference is that the excitation occurs from permanent magnets. Depending on the device, a magneto can provide electricity to the vehicle's on-board network, not just to start the engine. But usually devices of this type are used only to ignite the fuel mixture, since their energy is not enough for other needs.
Design and operation
This design is an alternating current generator. It uses a permanent magnet as an inductor, which is driven by a motor. This magnetic rotor, when rotating, forms a variable magnetic flux that induces an electromotive force in the stator coil.
On a car, this device has two windings: high and low voltage. The low-voltage winding is connected to the capacitor and contact breaker, and the high-voltage winding is connected at one end to ground and the other to the spark plugs.
The coils are located on a common U-shaped magnetic circuit, in which an alternating magnetic field is excited by the rotational movement of a permanent magnet. Usually the low voltage winding is part of the high voltage winding, similar to the device.
The magneto works as follows. When a permanent magnet rotates, an electromotive force is generated in the low-voltage winding. This winding is closed by the contacts of the breaker, as a result of which an induction current appears in it, formed by the alternating magnetic flux in the magnetic circuit, since the permanent magnet crosses it with lines of force. The magnetic flux changes within a few fractions of a second, resulting in a large current flowing in the closed coil.
IN certain moment the breaker opens its contacts, and the winding current rushes into the capacitor, resulting in low voltage harmonic oscillations. Since the contacts open at high speed, no breakdown occurs between them. Only after they open, the electromotive force in the circuit reaches its amplitude.
At this instant, a spark breakdown occurs on the spark plug, which is connected to the high-voltage winding, and the energy of the capacitor goes into alternating current high voltage, because oscillations continue in the low-voltage circuit, and the fuel mixture in the engine has time to ignite.
The duration of the oscillations is no more than one millisecond, which is determined by the size of the capacitance and inductance of the device. Next, the breaker closes its contacts again, and the whole cycle repeats.
As a result, we can say that a magneto is a magnetoelectric machine that converts the rotational motion of a permanent magnet into electric current. Some versions of this device are equipped with an additional winding located on the magnetic core. This winding serves to generate electric current for on-board network motorcycle or other vehicle. Permanent magnets located on the flywheel can perform two tasks - exciting high voltage to spark the spark plug, and exciting the generator. This combined device is called “magdino”.
Varieties
Devices are divided according to several factors.
In direction of rotation:
- Left.
- Right.
By the number of sparks per rotor revolution:
- 1-spark.
- 2-spark.
By overall dimensions:
- Small-sized. They are used in motorcycles, mopeds, outboard motors, and jet skis.
- Normal. Used in four-cylinder tractor engines.
Where is magneto used?
Most often, on outboard motors, motorcycles, and mopeds, there are magdinos that function together with voltage regulators and rectifier bridges. Their power is small and can reach only 100 W, but this is enough to operate side lights or charge. The advantage of Magdino is its light weight and small overall dimensions.
In gasoline engines, magnetos have been commonly used since ancient times, creating a spark in the spark plug, at a time when batteries were not yet so common. Currently, such designs are still found. During the war, German tanks were equipped with carburetor engines that used such an ignition system.
Aircraft piston engines have two spark plugs on each cylinder. Separate group spark plugs operate from a separate magneto - right and left group connected separately. This allows the engine to operate more efficiently and also increases the reliability of the ignition system.
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