The novice can solve the frequency converter common fault diagnosis and processing.(8)
1.9 common faults in operation
1.9.1 overcurrent trip
When starting, a litre of fast tripping, suggests that current is very serious, should check whether load short circuit, grounding, job card wall, mechanical transmission damage, starting torque of the motor is too small, and there motionless, inverter bridge inverter has been damaged.
In the operation of the reasons caused by tripping up setting time is too short, slow down time setting are too short, torque compensation (V/f ratio) setting is too big, due to low speed over current thermal relay, the adjustment of the improper, action set is too small also can cause current action.
1.9.2 overvoltage and undervoltage tripping
(1) overvoltage: the power supply voltage is too high, the deceleration time is too short, the brake unit is not working during the deceleration process or the brake unit is discharging too slowly, that is, the brake resistance is too large.The internal overvoltage protection circuit of frequency converter will cause overvoltage if there is a fault.
(2) undervoltage: the power supply voltage is too low, the power supply is out of phase, the rectifier bridge has a phase fault, and the failure of the undervoltage protection circuit inside the frequency converter will also cause undervoltage.
1.9.3 the motor does not rotate
The motor, wire and frequency converter are damaged, the line is not connected well, and the function Settings, such as upper limit frequency, lower limit frequency and highest frequency, are contradictory.Use external controls for timing, no options for presetting, and other unreasonable Settings.
1.9.4 stall occurs
Inverter in the slow down or stop the process, because of the slow time of setting too short or braking ability is insufficient, result in higher frequency converter internal bus voltage protection (also called overvoltage stall), frequency converter to lose control of the speed of the motor.At this point, a long deceleration time should be set to keep the bus voltage in the transformer from rising too high to realize normal deceleration control.
The acceleration of frequency converter in the process of growth, the setting time is too short or the load is too heavy, the grid voltage is too low, causing the converter overcurrent protection (also called a current stall), frequency converter to lose control of the speed of the motor.At this point, a longer period of growth should be set to maintain no overcurrent and achieve normal growth control.
1.9.5 main device self-protection of frequency converter (FL protection)
This protection is the self-protection that occurs when the main device of the frequency converter is not working normally.When FL occurs, many of the inverter parts of the converter have already passed through an inappropriate large current.The current was detected in a very short period of time, and without the power device damage before signal protection control, stop the power devices continue to be driven plate excitation and large current, continue to protect the power component.There are also power devices that have broken down and improperly passed the high current. After being detected, the drive plate stops the excitation of power devices.There is also heat - sensitive element action due to overheating, the occurrence of FL protection.