The supplier of the frequency converter braking unit reminds you that in the use of the frequency converter, improper selection and use of the frequency converter can often cause the frequency converter to not operate normally, and even lead to equipment failure, resulting in production interruption and unnecessary economic losses.
1、 Precautions for selection and installation
How to choose a frequency converter correctly
There are different types of frequency converters, and the correct selection should be based on the rated power, rated current, rated voltage, overload capacity, and usage requirements of various parameters of the frequency converter. In general, the basic functions of a regular frequency converter can meet the requirements of regular use, but it depends on the situation. For example, the maximum power of the frequency converter should be increased according to the load and usage environment. Moreover, some special industries also require the selection of relatively professional frequency converters.
2. How to correctly install a frequency converter
Carefully read the user manual and wire according to the instructions. In order to prevent electric shock caused by leakage inside the frequency converter, the frequency converter device should be stably grounded to avoid leakage caused by radio frequency interference.
2、 Correct use during operation
(1) When the speed of the motor is controlled by a frequency converter, the noise and temperature rise of the motor are higher than when using the power frequency. When the motor is running at low speed, due to the low speed of the motor fan blades, the temperature rise of the motor increases. In this situation, attention should be paid to reducing the load appropriately and paying attention to ventilation and cooling to prevent the temperature rise of the motor from exceeding the maximum limit.
(2) The impedance of the power supply line should be appropriately increased. When the frequency converter is connected to the low-voltage power grid, if the distance between the frequency converter and the distribution transformer is very close, or if the capacity of the distribution transformer is about 10 times greater than that of the frequency converter, if the circuit impedance is too small, it will cause a large surge in the frequency converter at the moment of input, directly damaging the rectifier components of the frequency converter. So if the impedance is small, an AC reactor should be installed between the transformer and the frequency converter.
3、 Proper maintenance during operation
(1) When using a frequency converter to start and stop to control speed, circuit breakers and contactors should not be directly operated, otherwise the frequency converter will lose control and cause serious consequences. So, in this case, instead of using circuit breakers and contactors, the control terminals of the frequency converter should be used for operation.
(2) When driving a regular motor with constant torque using a frequency converter, it is necessary to control the duration of low-speed operation, as prolonged low-speed operation can deteriorate the motor's heat dissipation effect and increase its temperature rise. Therefore, in the case of long-term low-speed constant torque, it is necessary to choose a variable frequency motor.
(3) During daily maintenance, it is necessary to check whether the resistance value of the external braking resistor of the frequency converter is greater than the allowable value of the braking resistor carried by the frequency converter. If the terminal of the brake resistor to be connected is plugged into the wrong port, it will cause a short circuit in the switch during braking. So, while meeting the braking requirements, it is necessary to make the braking resistance appropriately larger.