Motor frequency conversion starting cabinet
1. Start parameters
◦ Start time: can be adjusted in the range of 3-60 seconds, according to the power of the motor, load characteristics and system requirements, select the appropriate start time to ensure smooth motor start.
◦ Starting torque: Generally can be adjusted in the range of 50%-200% rated torque, for the motor started with load, it is necessary to set a higher starting torque to overcome the static friction and inertial force of the load.
◦ Acceleration time: Usually between 5-120 seconds, too short acceleration time may lead to a large impact on the motor and equipment, and too long acceleration time will affect production efficiency.
2. Motor adaptation parameters
◦ Suitable motor power: from a few kilowatts to hundreds of kilowatts or even higher, choose the right starting cabinet according to the power size of the motor in the actual application to ensure that the starting cabinet can provide enough power and protection for the motor.
◦ Number of motor poles: Common 2 poles, 4 poles, 6 poles, 8 poles, etc. Motors with different poles have different speed and torque characteristics, and the starting cabinet needs to be set and matched according to the number of motor poles.
3. Protect parameters
◦ Overcurrent protection setting value: Generally set to 1.2-1.5 times the rated current of the motor, when the motor current exceeds this value, the starting cabinet will cut off the power for a certain period of time to protect the motor and the line.
◦ Overheat protection operating temperature: For motor windings and power devices, etc., the overheat protection operating temperature is usually set between 130 ° C and 150 ° C. When the temperature exceeds this value, the starting cabinet will stop running.
◦ Undervoltage protection action value: Generally set to 70%-85% of the rated voltage. When the power supply voltage is lower than this value, the starting cabinet will trigger the undervoltage protection to prevent the motor from being damaged due to too low voltage.
4. Other parameters
Input parameter
◦ Rated voltage: 380V, 400V, 690V, etc. Different application scenarios and power systems choose different rated voltage levels.
◦ Rated frequency: Generally 50Hz or 60Hz, which is determined according to the frequency of the power grid in the region.
◦ Input current: refers to the maximum current that the control cabinet can withstand from the power side, depending on the power of the controlled motor and the load of the system, ranging from tens of amps to thousands of amps.
2. Output parameters
◦ Output voltage range: It can usually be adjusted in the range of 0V to similar to the input voltage, such as in the 380V system, the output voltage can be changed between 0-380V to meet the voltage requirements of different motor speed regulation.
◦ Output frequency range: Generally 0-400Hz or wider, the low frequency band can be used for the low speed operation of the motor, and the high frequency band can make the motor run higher than the rated speed to meet special process requirements.
◦ Output current: matched with the rated current of the driven motor, it should be able to meet the load current requirements of the motor in various working conditions, and has a certain overload capacity, which can generally reach 1.2-1.5 times the rated current.
3. Control accuracy
◦ Frequency accuracy: usually can reach ± 0.01%-± 0.1%, that is, the error between the actual output frequency and the set frequency is within a small range, to ensure the precise control of the motor speed.
◦ Voltage accuracy: Generally ±1% - ±5% to ensure the stability of the output voltage to protect the motor and other equipment from voltage fluctuations.
4. Other parameters
◦ Protection level: such as IP20, IP42, IP54, etc. IP54 indicates that the dust protection level is 5, preventing most of the ash
