Common failure analysis of MITSUBISHI inverter

E.UVT failure

Under MITSUBISHI voltage MITSUBISHI protection. Fault description: if the inverter power supply voltage drops, the control circuit may not play a normal function. Or cause the <a inverter href="/searchfanan.html?search=motor&select=7">motor inverter analysis torque analysis inverter analysis is insufficient, the increase of fever. To this end, when the power supply voltage drops to 300V, the output of the inverter is stopped. If there is no short circuit between P1 and P, it is under voltage protection function.

Troubleshooting: according to the fault interpretation, there are 2 places where there are failures. First: when the main circuit power supply voltage drops to 300V, or is P, P1 is not short, resulting in converter internal DC bus voltage is low, showing the UVT fault. Second: when the inverter internal DC bus voltage normal, but the detection loop is damaged, it will show the UVT fault.

The DC voltage detection in direct step-down mode after sampling, enter the optocoupler isolation, after entering the CPU. In the repair time will find the optocoupler will often be damaged, you can repair replacement of optocoupler

E.GF fault

Over current protection of the side ground fault. Fault description: when the inverter output side (load side) occurred in the ground, the flow through the ground current, the inverter stopped output.

Troubleshooting: according to the interpretation of the fault, the fault point is mainly in 2 aspects. First: the output of the motor side of the ground, when the current output, the frequency converter to detect the three-phase current and not zero, the frequency converter to stop the output, showing the ground fault. Second: frequency converter internal current detection fault.

The current detection circuit is through detection and sampling Hall, accesscontrol card. Maintenance as long as the testing Hall element, if the Hallelement is a good case, you can replace the control card, you can basically solve the problem.

E.OC1, OC2, OC3 fault

Accelerating, constant speed and deceleration of the over current fault. Description: when the inverter output current exceeds 200% of the rated current, when the inverter output current exceeds the rated current, the inverter output is stopped.

Trouble shooting: the first: whether the load is changing rapidly, or the load is too heavy. Second: the output is short circuit, including the motor side, there is no short circuit, if there is no short circuit, the inverter output is short circuit? Third: inverter internal hardware failure, including current detection, IGBT module, driver circuit damage, etc.

These problems appear to be gradually eliminated, the first to test the IGBT module, the test drive line, and then detect the current detection part of the line. These are the problems that are often encountered in maintenance

E6, E7 fault CPU fault

Fault description: loop around if the built-in CPU arithmetic at the scheduledtime without end, converter self-test to determine abnormal frequency converter output will stop.

Trouble shooting: the occurrence of such a failure to detect the connection between the control card and the power card is strong. If the connection line no problem, then it is possible is 1, the power card integrated circuit 1302 H02 damage 0.2, power card isolation optocoupler damage, CPU damage. The probability of occurrence of such failure CPU damage is relatively large.

E.LF fault

Output less protection, fault description: when the inverter output (load side)three-phase (U,V,W) has a disconnected, the inverter output will stop.

Trouble shooting: 1, the detection of motor side connection is normal, if normal is the problem of frequency converter. 2, frequency converter lack of phase, check inverter output voltage is balanced. If the output voltage balance, then the current detection problems. Check Holzer components as well as output status detection line. Can find the problem.