Professional soft starter and frequency inverter supplier and manufacturer in China


Q:The bypass of the soft starter cannot be closed ?

The user finishes using the soft starter but the bypass contactor does not pull closed. The causes may be as follows: (1) In the starting process, an error action is caused due to the relatively low value setting of the protection device. ( Just re-adjust the protective device) (2) In the debugging, the parameters of the soft starter are improperly set. (3) The control line is in bad connection. (Check the control circuit) (4) The control panel of the soft starter fails. (Contact with the factory of the soft starter)


Q:The non-full-phase fault of the soft starter ?

In the debugging process of the soft starter, there reports a non-full-phase fault, with failure indicator lighted but the motor no responding. The cause of the malfunction may be as follows: (1) The soft starter intrigues protection action due to the non-full-phase fault of the power supply.(check the power supply) (2) No load is connected to the output terminal of the soft starter (The soft starter will not work properly until the output terminal is connected to a load. ) (3) F2 should be set to 0 using multiple control mode. (4) The internal controllable silicon trigger line of the soft starter is in bad connection or the control board is in fault. (Contact with manufacturer)


Q:The switch jumps off when the soft starter starts ?

The switch jumps off occasionally during the start. The reasons can be as follows: (1) The setting value of the long time delay of the air switch is too small or the model of the air doesn’t match the motor. (Enlarge the parameter of the air switch or choose new type of air switch). (2) The starting voltage parameter of the soft starter is too high or the starting time is too long. (Lower the starting voltage properly or shorten the starting time. ) (3) The soft starter tends to issue wrong instructions and induce early bypass due to the relatively big fluctuation of the power grid voltage in the start process. (It is suggested that users do not start high power motors at the same time.) (4) Full load start (Try to reduce load when starting. )


Q:The soft starter is overheated when it starts ?

(1) Too high temperature caused by frequent starts activates the over-heating protection function of the soft starter. ( The number of starts of the soft starter should be limited to less than 6 times per hour, and special attention should be paid for the heavy load. ) (2) During the starting process, the soft starter’s long working to protect elements from bypassing by the contactor intrigues the protection action. ( Check the peripheral circuits for SJR2-5000 series) (3) Too long time starting due to heavy load intrigues over-heating protection action. ( Try to lessen the load when the starter starts) (4) The parameter setting is inappropriate like too long time and too low starting voltage. ( Raise the starting voltage.) (5) Thermocouple or master control panel is damaged. ( Contact the factory.)


Q:The silicon control of the soft starter is damaged ?

(1) Over current punches the soft starter through when the motor starts. ( Check whether the power rate of the soft starter matches the power rate of the motor and whether the motor is grounded or inter-turn short circuited. (2) Frequent starts or high temperature will damage the silicon control. (Limit the number of starts) (3) Check whether inlet lines of the power supply and the motor are loosened. (4) Check whether the modular of the soft starter or the silicon control is punched through and whether their trigger gate drive resistor meets the requirements in normal situation.( generally 10-30 ohms. ) (5) Check whether the socket of the connecting wire is loosened.


Q:No display on the frequency inverter ?

Check whether the power put in of the inverter is consistent with the rated voltage by a multi-meter. Check whether the indicator of CHARGE is lighted. If this indicator is off, the error lies in rectifier bridge or snubber resistor; If the indicator is on, the error probably lies in the part of switch power supply.


Q:The motor doesn’t move after the frequency inverter runs ?

Check whether there is balanced three-phase output among U,V and W. If there is, it means the motor circuit or the motor itself is broken, or the motor is stuck due to the mechanism problem; If there is no voltage output, most probably the driving board or the outputting modular is broken.


Q:The converter shows normal when electrified , but the air-breaker switches off after the operation ?

Check whether there is a short circuit between the output module. Check if there is a short circuit or grounding in the lead wire of the motor. If the trip is the occasional and the distance between motor and inverter is big, then consider adding an output AC reactor.


Q:Can the frequency inverter be used to control and adjust the speed of the single phase motor? ?

In most cases the frequency inverter cannot be used for single phase motors. Any casual use of the frequency inverter will cause damage to the equipment. The reason is explained as below: 95% of the single phase motors found in the market are single phase capacitor split phase AC motors, which start the rotor by changing the phase difference between the winding current through the capacitance. Therefore this is big difference between the starting principles of the single phase motor and the three phase motor and another more capacitance in the motor construction will bring latent problems to the frequency inverter: (1)The problem of high frequency resistance of capacitance. Inverter output waveform is SPWM wave. The high frequency harmonics which have a certain damage to the capacitance of several hundred Hertz, make the capacitor heated and even explode. (2) The effect of operating capacitance on frequency conversion. With the application of the frequency inverter,the absorption and release of the power supply of the running capacitor will block the "dead zone" in waveform of the frequency inverter, resulting in the public conduction between upper bridge and lower bridge, that is, short circuit, and resulting in the burning of the power parts of the inverter