How to choose the brush of the AC series motor?
1. How to choose the brushes of the rotor collector ring of the wound asynchronous motor?
It is mainly determined according to whether the working conditions of the brush meet the current density (a/cm2) and the linear velocity (m/s) of the peripheral edge of the collector ring. Determine the formula:
Brush current carrying capacity (a) = brush current density (a/cm2) × brush width l (cm) × brush thickness b (cm) ≥ motor rotor rated current (a) Linear velocity at the peripheral edge of the collector ring (m/s) = motor rated speed (r/m)/60 (s) × collector ring circumference (m) ≤ specified range for brushes (m/s)
The commonly used brushes are non-ink brushes, electrochemical graphite brushes and metal graphite brushes. In use, attention should be paid to frequently check the brush activity, brush pressure and degree of wear. The brush should be able to move up and down freely in the brush holder without jamming. When the brush is stuck, smooth both sides of the brush on the emery cloth.
The pressure of the brush should be adjusted appropriately according to the type and model of the brush. At present, most of the brush compression springs attached to the brush holder are tension and compression springs, and their pressure gradually decreases with the wear of the brush. Therefore, during the operation of the motor, the brush pressure should be adjusted at any time.
2. In the transformer sfz-32000/220th, what are z and th?
z means on-load voltage regulation, th means use in humid tropical regions.
11. What should be paid attention to when placing a 60hz motor on a 50hz power supply?
This is because the current frequency of the motor is lower than the design frequency. To reduce the no-load back electromotive force generated during the rotation and increase the no-load current, which will cause damage to the motor, the no-load voltage is required to be reduced.
In the variable frequency speed regulation technology, the frequency of the motor and the voltage of the stator are changed at the same time. That is, when the frequency drops, the voltage also drops at the same time, so that the motor will not be over-current, and the ideal operating effect will be obtained.
3. For the same motor, is the resistance of the 50hz and 60hz motors the same?
If the output power is the same, the resistance is the same
4. Can AC servo motors be controlled by inverters?
Due to the difference in performance and function between the inverter and the servo, and the application is not quite the same, it is not possible:
1) In the occasions of speed control and torque control, the general frequency inverter is not very demanding, and there are also inverters that add position feedback signals to the upper position to form a closed-loop frequency conversion for position control, and the accuracy and response are not high. Now some frequency converters also accept the pulse train signal to control the speed, but it seems that they cannot directly control the position.
2) In the occasions with strict position control requirements, it can only be realized by servo. In addition, the response speed of servo is much higher than that of frequency conversion. Some occasions with high requirements on speed accuracy and response also use servo control, which can be controlled by frequency conversion. The occasion of the movement can almost be replaced by the servo.
The key is two points: one is that the price of servo is much higher than that of frequency conversion, and the other is the reason for power: the largest frequency conversion can achieve hundreds of kw, or even higher, and the largest servo is tens of kw. The basic concept of servo is accurate, precise and fast positioning. Frequency conversion is a necessary internal link of servo control, and there is also frequency conversion in servo drives (stepless speed regulation is required).
5. Can the speed regulating motor be started frequently?
The speed-regulated motor can be started frequently. The motors used for debugging in our company are all speed-regulated motors, which are often started frequently without any problems. However, it is of course best to minimize frequent startups. No matter how many times the motor is started frequently, it will damage the motor.
Hope you can choose the brush of the AC series motor.
