The fork speed regulating motor has remanence, how to demagnetize?

I feel that the remaining magnetic force of this kind of magnetic speed regulating motor is not enough to produce the situation you said, and the possibility of selenium steel sheet generating residual magnetic force is very small. I feel that there is something wrong with your control part, that is, there is a problem with your speed control circuit, and you can't completely cut off the coupling current, the simplest test method is to untie the coupling current wiring, so that the magnetic coupler has no power coupling, if the motor can not output power correctly, it can only mean that there is a problem with your control part. If you can continue to output power, it means that there is a problem with the mechanical part of your magnetic coupling and needs to be dismantled and repaired.

Hope to solve your problem.

Steps to remove remanence from the copy workpiece:

Magnetically conductable metal workpieces are sucked onto it, the power supply is cut off, and an electromagnet with a power frequency coil is placed.

Turn on the electromagnet, turn on the 50Hz alternating current, magnetize its interior, and take the parts that need to be demagnetized back and forth many times to approach the most magnetic part of the electromagnet before leaving.

After repeating the same direction several times, the magnetism will recede, causing the magnetic field to disappear.

Use an electromagnet of a power frequency coil to turn on the 50Hz alternating current, and take the parts that need to be demagnetized back and forth many times to approach the most magnetic part of the electromagnet before leaving, and the magnetism will recede.

Conversely, if you draw a magnetizable metal workpiece to it and then cut off the power supply, you will magnetize it.

Be sure to pay attention to safety when operating!

Use a degausser, if the volume is not large, you can use the degausserizer of a color TV.

It is to use a gradually weakening alternating magnetic field to repeatedly magnetize until the magnetic field disappears and the remanence is gone.

Remanence: Under the excitation of the magnetic field intensity h generated by the electric current, the ferromagnetic material (such as the core) is magnetized and the degree of magnetization is described with the inductive intensity B. After magnetization, if the current excitation is removed, so that h = 0, the magnetic induction intensity in the ferromagnetic material decreases, but it is not zero, that is, b ≠ 0, this phenomenon is called ferromagnetic material has remanence characteristics.

The remanence of ferromagnetic materials can be weakened or disappeared by applying an appropriate reverse magnetic field, or by applying high temperatures or vibrations to them.

How to eliminate remanence.

Vibration, heating, can be demagnetized.

It is placed in an alternating magnetic field so that it is demagnetized.

To eliminate remanence, it is necessary to add a magnetic field in the opposite direction, and when the reverse magnetic field increases to a certain value, the B value becomes zero, and the remanence disappears completely.

What is a laxative.

Some amplifier filter outputs are terminated with a fixed resistor connected in parallel to the load, called a bleeder resistor.

The function of venting is: when the sine wave is cut off at the maximum peak moment, the residual charge on the capacitor C1 can not be released, and will exist for a long time, if the human body touches the metal part of C1 during maintenance, there is a strong possibility of electric shock, if the residual charge can be discharged, it can ensure the safety of man and machine.

How to vent.

You can add a discharge resistor: the effect of the discharge resistance is to discharge the voltage stored on the capacitor after the power supply is powered off, especially when overhauling a high-voltage and large-capacity capacitor circuit, the failure of the discharge resistance will endanger life safety, so even if there is a discharge resistor when overhauling this circuit, it is necessary to carry out a short-circuit discharge operation.

Add an anti-magnetic cover, if you know electronic knowledge, add a degaussing circuit, which can generally be found in phosphor screen TVs.

There are special degaussing equipment or manufacturers, look for it!

Under normal circumstances, the asynchronous motor cannot be demagnetized, and the coal mine motor needs to be replaced if it loses explosion.

Demagnetization is only replaced. There's no good way.

Are you talking about synchronous, or permanent magnet?

All you need to do is energize the excitation windings of the generator that has lost remanence.

Note: 1. The direction of the excitation current, according to the current direction of the original generator system to supply the excitation winding.

2. The excitation voltage used is the voltage supplied to the excitation winding according to the original generator system, not too much, it can be smaller, and the battery can be used generally.

Question addendum: It is best to only connect the excitation winding to the electricity, if the excitation winding is connected to the brush of the original generator, although it is possible, there will be a large current flowing through the armature.

Normally, the core will have remanence, which helps the establishment of the starting voltage, and if the remanence disappears, it is called demagnetization. Without remanence, there is no starting voltage, and there is no excitation (the excitation part requires electrical energy). The solution is; An appropriate DC voltage is added to the excitation coil to establish magnetism to the core.

Remove the magnetizing power supply, and then you can generate electricity normally.

One is to rely on remanence to trigger power generation, and the other is to force excitation power generation. A generator that generates remanence cannot generate electricity if the core does not have remanence. If it is forcibly excited, there is no need for remanence, at the beginning of power generation, the excitation coil will have a DC power supply (battery) provided outside the motor to provide electrical energy to establish a magnetic field, and then the exciter will control the power generation output.

Use a 12V battery to contact the copper rings on both sides of the carbon brush for 1-2 seconds. Choose the one with a small spark and the right direction. If the spark is large, the motor is OK.

Remove the excitation wire from the voltage regulator, pay attention to the positive and negative poles, and use direct current to pass it over, and it will be OK in 1 2 seconds. It's nothing more than magnetizing the iron core, but it's really not possible to make a magnet stone and pay attention to the direction of the magnetic pole to suck it down, so it's safe, right?

Here's a word about it: it's not "other motivation", but "self-motivation" generator.

It is not caused by remanence, it is the absence of magnetism, and if the self-excited generator loses magnetism, it will not be able to generate electricity. This is not to demagnetize, but to be magnetized.

Solution: At this time, first see if the two slip rings are very dull, grind them with an abrasive cloth until they become bright, if not: 1:

Take a very thin fuse, connect two of the "three-phase four-wire" on the generator (ask it to short-circuit), and then start the engine, then the voltage will come up, the fuse will blow automatically, and everything will be OK! If that doesn't work, try the second method; 2: If you don't understand the diode, open an iron ring on the back cover of the generator, you can see two slip rings (golden), and then see the carbon sand, then you take a battery, any size can be, then start the generator, hold the positive and negative wires on the battery with your hands, aim at the two carbon sand corresponding to the slip rings and hold down, know to see the generator voltage rise and move away.

If it doesn't reflect, try swapping the positive and negative poles of the battery. If the voltage is no longer available immediately after removal, the diode is broken, and the diode should be replaced.

Separately excited generators generally have several exciters. (Main exciter.) Sub-exciter).

If you don't connect the excitation voltage and send out 8 volts of electricity, it means that the rotor has magnetism, there must be remanence in the absence of excitation voltage, and it doesn't matter if you have remanence, if you want to go, I think you can add appropriate alternating current to the rotor coil to remove it.

When no excitation is added, the terminal voltage is 8V, which is caused by remanence. The remanence of such a small-capacity unit cannot be removed, and without remanence, the generator will not be able to establish the rotor magnetic field and will not be able to generate electricity. The remanence at this time is equivalent to the initial excitation of the generator.

It is necessary to rely on the voltage of 8V to establish the rotor magnetic field, so as to enter the self-circulating excitation process to gradually increase the voltage of the unit, and finally reach the rated voltage value. At the same time, after closing the outlet switch, you can generate electricity under normal load.

The first floor is not on the side at all, pure nonsense.

The second floor is used as an alternator, and "when the exit switch is closed at the same time, it can generate electricity under normal load." ”

The 3rd floor did not give a solution.

The one on the fourth floor is also used as an alternator, and "if it is not connected to the excitation voltage, it also emits 8 volts of electricity, which means that the rotor has a magnetic .......""The rotor is connected to AC demagnetization, which is really a trick.

It doesn't matter if there is voltage, the key is whether the owner's gantry planer motor is still rotating slowly after the generator cuts off the excitation!

If you don't turn, don't care. If turned, then:

Some gantry planers have a braking device, please check whether it is out of order.

This advice to the landlord:

Add a switch between the generator armature and the motor armature, and open and close together with the generator excitation power switch. In this way, when the generator excitation is disconnected, the generator and the motor are cut off, and there is naturally no problem.

What is the harm of having 8V residual voltage? To demagnetize once, it is a bit troublesome to degauss every time you shut down.