Technician B says that most stators contain three separate windings so they can produce both positive and negative voltage at all times.
How many windings are in A typical alternator stator?
three
In modern vehicles the electric power is generated by an alternator mechanically coupled to the engine. The alternator normally has a rotor field coil supplied with current through slip rings. The stator is fitted with a three-phase winding. A rectifier is used to convert the power from alternating to direct form.
How many windings should A typical truck alternator have?
The alternator stator has three internal windings wound 120 degrees between phases and it requires nine diodes in ‘bridge’ configuration to rectify the output. The voltage is controlled by a solid-state regulator that maintains the output in the range stated in the notes above.
How many diodes are used in A typical 3 phase full rectification truck alternator with A diode trio?
A half-wave 3-phase rectifier is constructed using three individual diodes and a 120VAC 3-phase star connected transformer. If it is required to power a connected load with an impedance of 50Ω, Calculate, a) the average DC voltage output to the load. b) the load current, c) the average current per diode.
Which winding in an alternator are connected to the diodes in the rectifier?
What is used in an alternator to rectify AC to DC?Which windings in an alternator are connected to the diodes in the rectifier? Stator windings. How many windings should a typical truck alternator stator have?
How stator winding is done?
A three-phase set of stator windings is inserted in slots in the stator iron. These windings may be connected either in a wye configuration, normally without external connection to the neutral point, or in a delta configuration. The rotor consists of a cylindrical iron core with conductors placed in…
How many phases does an alternator have?
three
An automotive alternator is a three-phase generator with a built-in rectifier circuit consisting of six diodes.
How much power does an alternator produce at idle?
13.8 to 14.3 volts
A fully charged battery should read over 12.6 volts. The actual output voltage produced by the alternator will typically be about 1-1/2 to 2 volts higher than battery voltage. At idle, most charging systems will produce 13.8 to 14.3 volts with no lights or accessories on.
How much current should an alternator put out?
Most late model alternators produce 120 to 155 amps or more. Current output increases with engine speed, from around 20 to 50 amps at idle up to the unit’s maximum output at 2,500 RPM or higher (refer to a service manual for the exact charging output specifications for your vehicle).
How can the rotor winding of the DC alternator unit be tested?
Visually inspect rotor shaft, slip rings and windings. Look for electrical shorts that appear as burnt black streaks on the windings. Scored rings or a bent rotor shaft indicates that the rotor needs to be replaced. No further testing is necessary.
Do alternators have built in voltage regulators?
Some alternators required revving the engine to a certain RPM in order to excite the alternator so it would turn on and start charging. External voltage regulators are eliminated and built into the alternator itself.
What component in an alternator rotates?
Rotor. The rotor is the spinning mass inside the alternator that rotates via the pulley and drive belt system. The rotor acts as a spinning electromagnet.
How diodes are connected in an alternator?
The charging output from the alternator flows through six diodes mounted in a rectifier assembly that convert the AC current into DC current for use by the electrical system. Referring to the schematic diagram, each set of two diodes connects to one of the three windings of the alternator.
What is the function of a diode trio in an internally regulated truck alternator?
Part of that circuit is another set of diodes mounted inside the alternator called the diode trio. The diode trio takes current coming from the three stator windings and passes a small amount through three diodes so that only the positive voltage comes through.
What are the six power diodes used for in a three phase alternator?
Six diodes are required to rectify the current from three stator windings, because each winding requires both a positive and a negative diode, to allow the current to flow to or from the end of its winding at the appropriate time.
How is stator winding resistance measured?
The windings resistance can be directly measured with an ohmmeter. Another method is to calculate the resistance by measuring the current trough every winding, using an ammeter A, when a voltage is applied and measured with a voltmeter V.
How much voltage should a stator put out?
For each 1000-rpm, a 32-amp stator should have 18 volts AC (VAC) per it. It should be 36 VAC by 2000. 54 VAC is what it should be at 3000 RPM. Each system should produce a certain amount of electricity.
What is 3-phase stator winding?
In its simplest form, the three-phase, random wound stator winding process consists of removing an existing winding from a stator and replacing it with a winding that duplicates the original winding performance characteristics.
What are the two types of stator windings?
Three types of stator windings were considered in the analysis: concentric single layer winding, concentric double layer winding and fractional concentric winding.
How do you calculate coil windings?
Refer to the manufacturer’s specification regarding the winding or measure it with a micrometer from the center of the wire coil to the outer section of the coil. Call this value “r.” A = 3.1415 * (1.5)(1.5) = 7.068 square meters. Find the number of wire turns and the length of the wire.
Is an alternator 3 phase?
The majority of all alternators in use today are three-phase machines. They are much more efficient than either two-phase or single-phase alternators.
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