Solid State Magneto (Altronic)
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| Illustration 1 | g00743710 |
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Magneto (1) Alternator (2) Stator | |
The main components of the Altronic magneto are alternator (1) and stator (2). The alternator generates electricity. The stator distributes the electricity. There are no brushes or distributor contacts.
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| Illustration 2 | g00579848 |
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Cross section of an Altronic magneto (3) Rotor (4) Vent (5) Speed reduction gears (6) Pickup coil (7) Drive tang (8) Storage capacitor (9) Rotating timer (10) Silicon controlled rectifier (SCR) (11) Output connector | |
The magneto's drive tang (7) is driven by the engine. The drive tang is attached to a shaft which turns the alternator's rotor (3). Rotation of the rotor causes rotation of speed reduction gears (5) and rotating timer (9). The power from the alternator charges storage capacitor (8). There is a separate pickup coil (6) and a separate silicon controlled rectifier (SCR) (10) for each cylinder. As the rotating timer passes over the pickup coils, a pulse from each coil activates each corresponding SCR in sequence. Each SCR releases the energy that is stored in capacitor (8). This energy leaves the magneto through output connector (11) and the ignition wiring harness to the ignition transformers. The transformers increase the voltage to the level that is needed to fire the spark plugs.
Solid State Magneto (Fairbanks Morse)
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| Illustration 3 | g00662676 |
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Cross section of a solid state Fairbanks Morse magneto (1) Plug (2) Coil (3) Plate and power board assembly (4) Distribution board (5) Capacitor (6) Alternator housing (7) Coil (8) Rotor (9) Silicon controlled rectifier (SCR) (10) Connector plug | |
Rotor (8) is driven by the engine through a drive coupling. The rotor moves by each coil (7) in order to produce voltage. The alternating current is sent through a rectifier which converts alternating current into direct current. The voltage is sent to the silicon controlled rectifier (SCR) (9) for the cylinder that will fire. Energizing the SCR enables the voltage that is stored in capacitor (5) to be released. The voltage goes through distribution board (4) to the transformer. As the rotor moves past each coil, the same electrical impulse is developed.
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| Illustration 4 | g00662340 |
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Cross section of a spark gap magneto (1) Distributor's disc (2) Cam (3) Distributor's gear and shaft assembly (4) Transformer (5) Coupling (6) Rotor (7) Condenser (8) Contact points (9) Rotor (10) Brush and spring assembly | |
Transformer (4) has a primary coil that is made of a heavy wire. One end of the primary coil is connected to ground on the transformer's core. The other end of the primary coil is connected to contact points (8).
Rotor (6) is a permanent magnet. When the rotor turns, electrical energy is produced in transformer (4). This will produce electricity in the wires.
When the voltage in the primary coil is at the highest peak in the alternating current's cycle, cam (2) opens contact points (8).
The contact points open in order to break the electric circuit. The flux around the wires of the primary coil will suddenly collapse through the primary coil. This produces peak voltage in the primary coil.
At peak voltage, the position of the distributor's disc (1) completes the circuit through the brush and spring assembly (4). The voltage travels to the distributor's block and through the low tension leads to the ignition transformers.
Condenser (7) prevents a spark that can cause damage to contact points (8). The electrical energy which normally makes a spark across the gap in the contact points goes into the condenser. When the contact points close, the electrical energy in the condenser moves back into the primary coil in order to provide voltage.
Impulse coupling (5) is used to cause an increase in the rpm of the rotor. When you start the engine the coupling is engaged. This will produce a stronger spark while the engine is started. The coupling is not engaged during normal engine operation.
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| Illustration 5 | g00679230 |
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Standard transformer | |
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| Illustration 6 | g00663208 |
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Integral Altronic transformer | |
An ignition transformer for each cylinder enables the ignition system to use low tension (voltage). Low voltage is sent to the transformers. The transformers increase the voltage to the high tension that is needed to fire the spark plugs.
In an ignition system that uses high tension, the loss of current through the wiring can be substantial. Routing of several wires that conduct high tension increases the chance of an insulation failure which can result in grounding of the current. Also, the current in the wiring can be affected in a manner that is similar to the current in a transformer. This can result in a crossover of the current between the leads. The crossover can cause a loss of power and misfire. An ignition system that uses low tension has these advantages over a system that uses high tension:
- Line loss through the wiring is reduced.
- The possibility of insulation failure and grounding of the current is reduced.
- The possibility of crossover is reduced.
For proper operation, the terminals of the transformer must be clean and tight. The negative transformer terminals have a "−" mark. These terminals are connected together and the circuit is grounded.
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| Illustration 7 | g00663105 |
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Spark plug and adapter (1) Cover (2) Spark plug wire (3) Seal (4) Spark plug adapter (5) Spark plug | |
Cover (1) keeps water, dirt and other foreign material out of spark plug adapter (4). Spark plug wire (2) goes through the cover to the terminal of spark plug (5). Seal (3) prevents leaks between the adapter and the cylinder head.
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| Illustration 8 | g00662973 |
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Instrument panel (1) Stop switch (2) Reset switch (3) Oil pressure gauge (4) Water temperature gauge (5) Start switch | |
The instrument panel is connected to the magneto and the gas shutoff valve.
A magnetic switch connects the magneto to ground. The engine oil pressure gauge and the water temperature gauge have switches that are connected to the magnetic switch. If the water temperature gets too high or if the engine oil pressure gets too low the magnetic switch is activated. The water temperature gauge prevents an overheated engine from running and/or being started. The engine oil pressure gauge prevents engine operation with low oil pressure.
The engine oil pressure gauge and the water temperature gauge will not make a connection to the magneto ground when reset switch (2) is pushed in and held. When you start the engine, press start switch (5) and the reset switch. The reset switch prevents the connection of the magneto to ground because of low engine oil pressure. Once the engine starts, normal engine oil pressure allows the switch to be released. The gauge is then ready to stop the engine when the engine oil pressure is low.
For normal stopping, press stop switch (1). The gas shutoff valve must be manually reset.
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| Illustration 9 | g00664281 |
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Ignition system diagram for the solid state Altronic magneto (G3304) (1) Spark plug (2) Ignition transformer (3) Ground for the magneto's case (4) Magneto (5) Instrument panel (6) Magnetic switch (7) Stop switch (8) Engine oil pressure gauge (9) Water temperature gauge | |
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| Illustration 10 | g00664366 |
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Ignition system diagram for the solid state Altronic magneto (G3306) (1) Spark plug (2) Ignition transformer (3) Ground for the magneto's case (4) Magneto (5) Instrument panel (6) Magnetic switch (7) Stop switch (8) Engine oil pressure gauge (9) Water temperature gauge | |
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| Illustration 11 | g00669020 |
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Ignition system diagram for the solid state Fairbanks Morse magneto (G3304) (1) Spark plug (2) Ignition transformer (3) Magneto (4) Instrument panel (5) Magnetic switch (6) Stop switch (7) Engine oil pressure gauge (8) Water temperature gauge | |
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| Illustration 12 | g00669031 |
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Ignition system diagram for the solid state Fairbanks Morse magneto (G3306) (1) Spark plug (2) Ignition transformer (3) Magneto (4) Instrument panel (5) Magnetic switch (6) Stop switch (7) Engine oil pressure gauge (8) Water temperature gauge | |
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| Illustration 13 | g00664212 |
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Ignition system diagram for the spark gap magneto (G3304) (1) Magneto (2) Spark plugs (3) Ignition transformers (4) Magnetic switch (5) Stop switch (6) Engine oil pressure gauge (7) Water temperature gauge (8) Instrument panel | |
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| Illustration 14 | g00668991 |
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Ignition system diagram for the spark gap magneto (G3306) (1) Magneto (2) Spark plugs (3) Ignition transformers (4) Magnetic switch (5) Stop switch (6) Engine oil pressure gauge (7) Water temperature gauge (8) Instrument panel | |
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| Illustration 15 | g00664384 |
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Wiring diagram with overspeed contactor and gas valve (1) Solenoid (2) Gas shutoff valve (3) Overspeed contactor (4) Shut off stud for spark gap magneto or pin H for Fairbanks Morse magneto or pin G for Altronic magneto (5) Magnetic switch (6) Stop switch (7) Engine oil pressure gauge (8) Water temperature gauge (9) Instrument panel | |