When this reversing voltage polarity is connected to a load, it causes a reversing current direction in the circuit. The quicker the shaft of the alternator is cranked, the faster the magnet spins, resulting in an alternating voltage and current that changes directions more frequently in a given length of time. This can cause damage to electrical components such as transistors and valves if they are not designed for such activity.
When the alternator shaft is stopped, the magnetic field collapses, but the diode remains reversed biased due to the body effect. As long as there is no power being fed into the battery, the diode will remain in this state until something triggers it into forward bias. This could be due to vibration or other movement causing the zinc particles on the surface of the battery to hit each other and create a short circuit that connects the positive and negative poles of the battery together. Once this connection is made, the battery becomes part of the circuit and any voltage from it will cause the diode to conduct, allowing current to flow through it and into the motor coil.
An example situation where this would be problematic is if there is a relay installed in the circuit with its contacts open. When the shaft is stopped, the magnetic field produced by the alternator won't be able to keep the diode reversed biased, so it will go into forward bias, connecting the positive and negative sides of the battery together.
An alternator, in conjunction with the battery, supplies electricity to the vehicle's electrical components. When the alternator pulley is rotated, alternating current (AC) flows via a magnetic field and generates an electrical current. This is subsequently converted to direct current (DC) via the rectifier. The DC from the alternator flows through the battery to power other electrical components of the vehicle. When the engine is turned off, the belt that drives the alternator stops, and the alternator shuts off.
The diode bridge spreads the voltage out evenly across all the cells of the battery while allowing only the positive side of the battery cell to be connected to the vehicle's electrical system. This prevents any damage to the battery caused by excessive voltage when the car starts from cold weather conditions or is otherwise activated. The rectifier also protects the battery from being damaged by preventing any voltage from appearing on its negative terminal when the positive side of the battery is connected to the electrical system.
Alternators use either semiconductor diodes or mechanical commutators to regulate voltage. Semiconductor diodes are less expensive than mechanical commutators but they can only handle a limited amount of current. For this reason, most modern automotive alternators use some type of commutation system. Commutation systems operate by switching electromagnets on and off which in turn switches the output of the alternator on and off.
The stator is permanently attached to the shell of the alternator and does not rotate. The magnetic field of the rotor sweeps across the stator windings as the rotor revolves, creating an electrical current in the windings. An alternating current is created by the spinning of the rotor. This type of motor is called a "induction" motor because the stator coils are what are actually induced into circuit when the rotor turns. The voltage applied to the stator coils is about twice that applied to the rotor, so wiring needs to be done with care. Care should be taken not to connect two circuits together or allow any exposed metal to come into contact with other parts of the assembly, otherwise you might get a short circuit.
There are three types of stators used in automotive applications: single-coil, three-phase, and six-point. The single-coil stator has only one winding which creates a voltage when it is swept through a magnetic field. This type of stator is used in equipment where reliability is important but size is not a concern. Three-phase and six-point stators have three or six separate windings, respectively, which create voltages when they are swept through a magnetic field. These types of stators are used in vehicles that need more output than a single-coil unit can provide.
Stators are made out of sheet steel with slots cut out for the copper wire to go inside.
When an alternator generates an alternating current voltage, the voltage flips polarity in a very specific way over time. When this polarity over time wave trace is graphed, it can be observed that it changes swiftly yet smoothly along the cross over line (point zero). A sine wave is the form of the curve created as a result of this process. The more often the voltage crosses over the point zero-line, the higher the frequency of the sine wave will be.
An electrical circuit must include two components: a source of electricity and something that will use it. An electric generator is the device that creates electricity. It does so by turning mechanical energy into electrical energy. The mechanical energy may be human or animal power, such as from a motor or windmill, or it may be solar power, such as from the sun shining on a spinning turbine wheel. Electricity from generators must be transmitted to other locations where it can be used. This may be done with a direct wire connection from the generator to the destination equipment, or it may be accomplished through an electrical distribution system comprising wires that connect all the generators together and then branch out to various outlets. These branches may be at home locations or in commercial buildings. At the end of each branch is a load, which is any equipment that uses electricity - lights, heaters, air conditioners, etc. The distribution system ensures that enough electricity reaches all parts of the community or building being served by the system.