• What is the role of the input side AC reactor?
    The reactor in the circuit generally has two functions:
    (1) to suppress the surge (voltage, current); (2) to suppress the harmonic current.
    Reactor in the use of the frequency converter is divided into input reactor, output reactor and DC reactor. Different reactor on the role of the inverter is also different.
    input reactor
    To limit the voltage mutation and switching overvoltage caused by electric shock, contained in the smooth supply voltage spikes, or smooth bridge rectifier circuit commutation voltage defects, effectively protect converter and improve the power factor. It can not only prevent the interference from the power grid, and reduce the pollution of harmonic current of rectifier unit on the grid.
    output choke
    The main function is to compensate the influence of the distribution capacitance of the long line (20-200m), reduce the leakage current of the electric motor, and can restrain the output harmonic current, increase the output high frequency impedance, and effectively restrain the dv/dt. To reduce the high frequency leakage current, to protect the frequency converter, reduce the role of equipment noise.
    DC reactor
    Connected between the inverter system of DC rectifier and inverter, the main purpose is will be limited in a specified value of superimposed on the DC current of the AC component and maintain current rectifier continuous, decreasing the current pulse value, the inverter operation more stable and improve the power factor of inverter.
  • Is the transducer output terminal connected with the contactor suitable?
    Usually case, inverter output does not recommend a contactor, if must be connected with a contactor, you need to follow the following principles: start, first contactor, and then start the inverter; shut down, to stop the inverter, and then disconnect contactors. It is absolutely not allowed in the operation of the inverter, the contactor cut or disconnect, because this will cause a huge impact current, damage to the inverter or motor, may lead to serious explosion.
  • In the application of rapid braking, how to choose the brake resistance?
    Selection of braking resistance need to calculate the resistance R and power PR, in order to buy Brake Resistance of standard in the market, the selection can be appropriate amplification (i.e. resistance than the calculated value is chosen small, choose a big power, but to consider the rated current of the brake unit), calculated as follows:
    1, the selection of resistance
    When braking, the regenerative energy of the motor is almost completely consumed on the braking resistance. According to the formula:
    Formula: U---- system stable brake braking voltage (for the 380VAC system generally take 700V)
    2, brake resistance of power choice
    In theory, the braking resistance is in agreement with the power and braking power, but the reduction is 70%. According to the formula:
    Pr---- brake resistance power
    ED---- braking frequency, that is, the proportion of the entire working process of the braking process
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