High-voltage thyristor soft starter is a soft start and a variety of protection functions in one of the new high-voltage motor soft start device. It can not only in the whole process of starting the smooth start of the motor, but also according to the motor load characteristics to adjust the parameters of the process of starting, Silicon and its simple structure, low prices, reliable, so in all areas of production More and more widely used.
In the high-voltage thyristor soft starter device, if you choose the rated current is too high high-voltage thyristor, you do not make full use of high-voltage thyristor performance, and the cost of the device is too high; if you choose the rated current is too small high voltage SCR , Silicon The device is running unreliable, serious will burn high-voltage thyristor. Therefore, the choice of high-voltage thyristor rated current is critical.
In the high-voltage thyristor soft starter device, each phase thyristor main circuit structure is: a pair of anti-parallel thyristors constitute a component, each phase consists of multiple sets of thyristor components in series. High-voltage thyristor triggers the use of optical fiber transmission. Silicon In the soft start process, the thyristor sequence conduction, and according to a certain degree of phase shift to change the motor input voltage. DSP control system according to set the starting current and motor current difference to move the trigger angle, limit the motor starting current, smooth start the motor, while the motor terminal voltage gradually increased. When the motor terminal voltage reaches the rated voltage, after the soft start process, Silicon close the bypass contactor, bypass the SCR valve assembly. Therefore, the SCR flow time is very short, the general flow time does not exceed 45s, up to no more than 60s.
(1) rated on-state average current IT under certain conditions, the anode - the cathode can be continuous through the 50 Hz sine half-wave current average.
(2) Positive blocking peak voltage VPF The positive peak voltage at both ends of the thyristor can be repeated when the gate open voltage is not triggered and the anode forward voltage has not exceeded the pilot voltage. The positive voltage peak of the thyristor can not exceed the parameter value given in the manual.
(3) Reverse sin fault peak voltage VPR When the thyristor plus reverse voltage, in the reverse off state, can be added at both ends of the thyristor reverse peak voltage. When used, Silicon this parameter value can not be exceeded by the manual.
(4) the control electrode trigger current Ig1, the trigger voltage VGT at the specified ambient temperature, the anode - the cathode with a certain voltage, Silicon the thyristor from the off state to the required state of the minimum control of the current and Voltage.
(5) Maintain current IH at the specified temperature, the control circuit, to maintain the thyristor conduction required minimum anode forward current.