Mitsubishi Electric’s A700 series and E700 D700 series general-purpose inverters are the most used in the market, and are suitable for high starting torque and high dynamic response applications. The E700 series is suitable for simple function requirements and is used in occasions with lower dynamic performance requirements, and the price is more advantageous. The following is a brief introduction to some of the new faults and corresponding handling methods of the two most widely used models of Mitsubishi inverters in the market:
1, E6, E7 failure
E6, E7 fault is not unfamiliar to the majority of users, this is a more common Mitsubishi inverter typical failures, of course, the causes of damage are many.
Integrated circuit 1302H02 is damaged. This is an integrated circuit that integrates the drive waveform conversion and multiplex detection signals in one IC. There are multiple signals associated with the CPU board. In many cases, problems with any signal on the IC can cause E6. , E7 alarm;
2, switching power supply damage
Switching power supply damage is also a common fault of A700 series inverters, eliminating some factors such as pulse transformer damage, switch FET damage, start-up resistor damage, and rectifier diode damage that we often mentioned before.
3, power module damage
The damage of the power module mainly occurs in the E700 series inverter. For a low-power inverter, since it is an intelligent module that integrates the power device and the detection circuit, it can only be replaced when the module is damaged, but the maintenance cost is high and no maintenance value is available. For the 5.5KW and 7.5KW E700 series inverters, the 7MBR series PIM power modules have been selected. The replacement cost is relatively low, and some damages can be done to such inverters.
4, OC1, OC3 failure
In the past, the author introduced the Mitsubishi inverter OC (overcurrent fault) many times will be caused by the following reasons (the current A700 series inverter as an example).
(1) caused by improper parameter settings, such as time set too short;
(2) Caused by external factors, such as motor winding short-circuit, including (short-circuit between phases, short-circuit to ground, etc.);
(3) Inverter hardware failure, such as Hall sensor damage, IGBT module damage.
Any one of the above detection points may alarm and may not operate normally. In the case of the detection method that we introduced before, we must pay special attention to whether or not the problem is normal. The detection direction mainly includes several components of the Mitsubishi drive circuit just introduced.
5, UVT failure
UVT undervoltage fault, I believe many customers will still encounter such problems in use, our common undervoltage detection point is the DC bus side voltage, after a large value of the resistance voltage divider sampling a low voltage value, and The standard voltage value is compared with the output voltage normal signal, overvoltage signal or undervoltage signal.