1. The contact resistance increases and the excitation current decreases
2. Carbon brushes and slip rings will overheat, which may cause fire in severe cases
3. between carbon brushes and slip rings Sparking occasionally occurs, leading to electrical corrosion of the slip ring and increased wear.
Treatment:
1. Adjust the carbon brush spring pressure to ensure good contact between the carbon brushes and the slip rings. the carbon brush and the slip ring
2. Before replacing the carbon brush, the contact surface of the carbon brush must first be polished to make the arc of the carbon brush consistent with the arc of the slip ring< /p>
3. Blow the slip ring with low pressure air each time you shift to prevent carbon dust buildup
4. If the slip ring is very worn, it must be polished and replaced with one. a softer carbon brush
Why does the motor carbon brush spark?
Factors causing the carbon brush to heat up: 1. The dispersion of the resistance of the carbon brush increases, which increases the heating resistance of the carbon brushes. 2. Carbon brush jam. After the carbon brush is turned on, the brush body expands and easily gets stuck in the brush holder; some carbon brushes will have obvious jamming on the upper edge of one side of the brush holder and the lower edge of the other side due to vibration, non-vertical brush holder, etc. These types of resistors can still measure current with a clamp meter, but they can easily be misled. At this time, the carbon brush failed, causing an increase in the current distributed by the other carbon brushes and an increase in heat generation.eur. 3. Carbon brush pressure decreases. Although it is a constant pressure brush handle, the pressure of each spring is different. When the pressure is low enough, the contact becomes unstable, the contact pressure drop increases, and heat generation increases significantly. At the same time, due to insufficient spring pressure, the contact surface between the brush holder and the carbon brush is lengthened, which increases the friction resistance on the carbon brush side, and the carbon brush coal is stuck in the support. 4. A film of air forms on the contact surface of the carbon brush. When the carbon brush operates at the maximum allowable speed, it is easy to produce an air film and jump on the contact surface, and the current flowing through the carbon brush is unstable. The grooves and grinding on the surface of the slip ring are larger and the surface ofContact with the carbon brush can destroy the air film. However, the grooves reduce the actual contact area of the carbon brush. 5. Formation of the oxide film of the slip ring. The oxide film of the slip ring is too thick, the contact resistance of the carbon brushes increases, and the excitation current is shunted to other carbon brushes with low circuit resistance. 6. Destruction of the current balance. Under normal circumstances, the contact tightness between the carbon brush and the slip ring is large, the contact pressure drop is small, the working conditions of all carbon brushes are similar, the current of each brush carbon is close to the same, the average temperature of the brush body is low, and the current between the carbon brushes is relatively stable and balanced. After a certain period of operation, factors such as oxide film, air film, long resistancee, etc. appear, the carbon brushes are worn short or the spring pressure is reduced, the contact tightness of the contact surface of the carbon brushes is reduced, the current between the carbon brushes is redistributed, and the current of each carbon brush The difference increases and is in unstable equilibrium. This stage takes time, evolves gradually and is not easy to detect. When the ambient temperature increases or the excitation current increases, damage to the balance may occur at any time.
Heat treatment 1. When the heating is in the initial stage and the heating temperature is not higher than 100°C, you can adjust some carbon brushes which do not work well. For example, replace worn carbon brushes with low operating current; Adjust or replace some of the less elastic brush holder springs to optimize current distribution. 2.Appropriately reduce the reactive load of the generator, reduce the excitation current, reduce the carbon brush operating current, and reduce heat generation. 3. When individual carbon brushes are broken, the excitation current can be reduced first; when the ring fire occurs, the excitation current can be reduced significantly. Excitation current, adjust the current balance of the carbon brushes before replacing the carbon brushes, do not forcibly replace a large number of carbon brushes. 4. Clean air vents and keep air ducts clear.
Emergency treatment for heating: When the temperature exceeds 120°C, replacing the carbon brush or adjusting the brush holder cannot reduce the overall temperature, because the new carbon brush has less contact area with the slip ring and is not fluid. Whatever the quantity ofcurrent it distributes, thermal conduction will increase its temperature. The most important measure at present is to lower the working temperature and improve the working conditions of the carbon brush and brush holder. 1. Method for removing defective carbon brushes During normal operation, if the working current and ambient temperature do not change much, but the carbon brush temperature rises significantly, it may be caused by a small number of failures of carbon brushes (such as increased resistance, reduced spring pressure, carbon (the brush is long and the carbon brush is broken, etc.). At this point, the carbon brush causing the heat should be identified with precision and removed so that the other carbon brushes can operate normally and enter a normal equilibrium state. The key to this approach is to make accurate judgments. Defective carbon brushes present.usually have vibrations, a large current and sometimes their temperature is higher than the overall temperature. If you cannot judge accurately, you can use the test method and remove a brush holder at regular intervals until the overall temperature drops significantly. Once the system temperature returns to normal, reinstall the treated carbon brushes.
What's wrong with old carbon brushes sparking in small motors?
Vacuum cleaners typically use series-excited or compound-excited motors with speeds high, usually thousands to tens of thousands of revolutions. It is normal for the brush to spark slightly. If it produces significant sparks, you should check whether the carbon brush is seriously worn, whether the brush spring is broken or has insufficient elasticity, and whether the frame and collardrive are defective.
What are the consequences of sparking from generator carbon brushes?
Slight sparks from the carbon brushes of the generator have no effect if not dealt with in time, the sparks will become bigger and bigger. causing significant heat and burning. Defective carbon brushes and slip rings can cause the field circuit to be interrupted or the brush holder to burn out.
How to solve motor carbon brush sparking problem
Whether the generator is DC or AC, if the DC generator carbon brush sparks, it means that the electric coil is short-circuited. circuited. Find the short and separate it. If the alternator carbon brush sparks, it means the carbon brush cannot be replaced. It is also possible that the copper ring in front of thecarbon brush is too dirty. Just sand it with sandpaper and you'll be fine.
Why do carbon brush tools spark?
Carbon brush tools are switched using carbon brushes. When working, electricity passes through the carbon brushes to each winding.
What are the consequences of a spark on the motor carbon brush?
Burn the coil and cause partial damage by short circuiting the coil. . . . . . . . .
How to deal with generator carbon brush sparking?
Whether the generator is direct current or alternating current, if the carbon brush of the DC generator produces sparks, it means that the electric coil is short circuited. Find the short and separate it, okay! If the alternator carbon brush sparks, it means the carbon brush cannot be replaced. It is also possibleIt is possible that the copper ring in front of the carbon brush is too dirty. Just sand it with sandpaper and you'll be fine.
Engine ignition problem?
Motor ignition ghostThe electrician had to clean the commutator and replace the carbon brushes over and over again. After each repair, the sparking improved slightly, but over time the sparking gradually increased and the sparking could not be eliminated. Today I replaced a new one. of the same motor model, follow the parameters of 590, the speed is given as 87%, the current is 52% and the armature voltage can rise up to 400V. It turns out that at the same speed, when producing the same type of cable, the current reaches 59%, and the armature voltage can reach 350 V. Is it possible to diagnose a problem with the motor rotor ?
How to handle the “motor carbon brush sparks” fault?
He exThere are many reasons why the motor carbon brush sparks. Generally, replace the carbon brush, arrange the changer, adjust the brush holder, etc. If you are unable to do so, you can send it to us for repair.
The motor's carbon brushes often spark. Carbon brushes are easy to burn out. How to solve the problem? Thank you for your question.
Clean the powder on the collector and. make the carbon brush contact area smooth and smooth, the front and rear bearings should be replaced if the gap is too large.
What happens if one side of the motor sparks after replacing the carbon brush?
There is a jam between the carbon brush and the brush housing and the brush housing cannot slide freely. is loose and poorly positioned. The brush contact surface is not ground.