It depends on the excitation method of the DC motor. There are two main categories of excitation methods:
1. Separate excitation method, which means that the excitation current of the main pole magnetic field winding (stator winding) is supplied by another DC power supply and has no electricity. connection with the armature circuit. That's what you said about adding DC power to the stator.
2. Self-excitation mode means that the excitation current of the main magnetic pole excitation winding is supplied by the motor armature itself.
I guess what you want to ask is how to power the magnetic poles (stator) to generate a magnetic field before the generator generates electricity, right?
This is the use of residual magnetism. Residual magnetism in the stator can provide a forward magnetic fieldthe generator does not generate electricity.
I once encountered a generator that had been idle for a long time. When it was necessary to generate electricity, there was no residual magnetism and the generator could not start. An experienced technician connected a battery to the stator. winding and starting the generator, and it worked normally!
When a generator produces electricity, if there is no equipment using electricity, where does the electricity it generates go?
Method to detect car generatornot producing electricity: usemultimetervoltage equipment to test , turn the multimeter knob to DC voltage 30V In socket, connect the red test lead to the generator armature terminal and the black test lead to the case. Let the engine run above average speed. The standard ofThe 12V electrical system voltage is about 14V. The 24V electrical system voltage standard. The value should be around 28V. If the measured voltage is the battery voltage, it means that the generator is not producing electricity.
A generator refers to a mechanical device that converts other forms of energy into electrical energy. A general generator converts the energy contained in various primary energy sources into mechanical energy through a prime mover and then. generates electricity. The machine converts it into electrical energy and sends it to various energy consumption locations via energy transmission and distribution networks.
Why is the car's alternator not charging?
Cause of the fault: The "magnetic field" terminal of the alternator is grounded; the wires are incorrectly wired; the battery is short-circuited; ;
Diagnosing problems: 1. Check the wires forr detect wiring errors. Start the engine, run it at medium speed and remove the wire from the regulator terminal. If the ammeter still shows a charge, this means that the magnetic field terminal of the generator is grounded and its insulation must be ensured. If the ammeter indicates discharge, check and replace it. regulator.
2. For a charging system equipped with a contact voltage regulator, when the motor is running at medium speed, reduce the elastic force of the regulator spring. If the charging current decreases, it means the original spring. the tension is too high. Debugging needs to be done; If the charging current is still large, the regulator should be removed and the affected parts inspected.
3. After the above inspection, all components are normal and the battery should be checked for internal short circuit faults.
The generatornot charging?
There are about 7 common reasons:
1. The regulator is damaged.
2. The magnetic field coil is broken.
3. The brush is stuck or the slip ring has poor contact.
4. There is an open circuit between the instrument fuse and the generator.
5. The generator drive belt is loose.
6. The diode board is burnt out.
7. The rotor coil is shorted or open. This is because the generator's magnetic field current is too large. Is the diode deteriorated enough to remove and measure?
In daily life, we consume a source of energy almost every moment? Electricity As we all know, the electricity we use is usually generated by generators. An interesting question arises: when the generator produces electricity, if there is no equipment that useselectricity, where does the electricity it produces go? Let's talk about it today.
We all know that the basic principle of a generator is electromagnetic induction. Generally speaking, when a generator is operating, its metal coil is constantly cutting the magnetic lines of force (this can also be a passing rotating magnetic field). by metal coil), under the action of electromagnetic induction, the free electrons inside the metal coil tend to move directionally, thereby generating an electromotive force at both ends of the coil.
But the generation of electromotive force does not mean that the generator generates electricity. Only when the generator is connected to an electrical circuit can the generator be considered to have generated electricity. When there is no power to the equipment, the operating generator circuit is essentially in a dead state.connected. In this case, the generator is not producing power, and of course there is no way to talk about it? the electricity it produces goes? Such a question.
Such a situation is called a no-load generator. So when the generator is idle, where is its energy consumed?
Among different alternators, synchronous generator can be said to be the most commonly used one, so here we take this generator as an example to illustrate this problem.
You may think that all the energy of the generator when it is idle is consumed by the mechanical losses of the generator itself (such as bearing friction losses, ventilation losses , etc.), but in fact, in addition to the above In addition to mechanical losses, the synchronous generator will also have other energy consumption.
According to the principle of electromagnetic induction, a magnetic field must exist inside the generator toproduce electricity. When the generator is no-load, although there is no external current output, its two poles will remain fixed. electromotive force, to ensure that current can be delivered as soon as the load is connected, which means that the magnetic field in the generator must always exist. So where does this magnetic field come from? Here we need to popularize the concept of excitement?.
In simple terms, “excitation” involves providing the magnetic field necessary for the generator to operate. The “excitation” of the synchronous generator uses current (direct current) to generate the working magnetic field through special coil windings. (This current is called "field current" and the coil winding is called "field winding").
We see that when the generator is empty, in addition to mechanical losses, maintaining the generator's own magnetic field also requires ae energy consumption.
Some people might wonder after seeing this: When the synchronous generator first starts, there is no current in the excitation winding and there is no magnetic field. So how is the initial electricity generated?
Depending on different uses, the excitation windings of small synchronous generators are generally placed on the rotor, while those of large ones are placed on the stator. Let's take a small synchronous generator as an example.
Without a magnetic field, electricity cannot be generated, but fortunately, under normal circumstances, synchronous generators have iron cores with residual magnetism retained in the generator rotor. (Note: Residual magnetism refers to the magnetic field that remains in ferromagnetic materials after the external magnetic field disappears. It is usually relativelyweak. If the generator has no residual magnetism, it must find a way to magnetize it, otherwise it won't. be able to produce electricity) There is no current in the excitation winding, but the iron core in the rotor still has residual magnetism. When the generator starts, the magnetic field carried by the rotor begins to rotate and continues to pass through. the metal coil on the stator, thereby generating The current used for "excitation" is sent to the "excitation winding" after rectification, which increases the magnetic field of the rotor and generates a larger current during rotation?
Through such positive feedback, the generator output voltage will slowly increase until it finally reaches the rated voltage, at which point the load can be connected. This is also the reason why a general diesel generator requires the load end to be disconnected lduring startup and can only be connected when the output voltage stabilizes.
A brief summary: When the generator is working, if there are no electrical appliances, it will not produce electrical energy, but it will have its own energy loss. For synchronous generators, it will also generate some secretly. electricity to enhance and maintain its own magnetic field.