SERVICE HOTLINEHow to test and judge the various problems that DC motor governor meets? In the process of daily maintenance of DC governor often encounter a variety of problems such as peripheral line problems, poor parameter setting or mechanical failure. If it is DC governor fault, DC governor how to judge which part of the problem, here is a brief introduction.
Static test of DC motor governor
1, test the rectifier circuit, find the DC governor internal DC power supply P and N end, the multimeter is adjusted to the resistance X10, red bar to P, black bar according to R, S, T, there should be about dozens of European resistance value, DC governor and basic balance. Instead, the black bar is connected to the P terminal, and the red bar is connected to R, S, and T in turn, with a resistance value approaching infinity. Connect the red watch rod to the N end and repeat the above steps to get the same result. If there are the following results, the DC governor can determine that the circuit has been abnormal, A. The resistance value of the three-phase unbalance, can indicate the fault of the rectifier bridge. B. When the red table rod is connected to the P end, the resistance is infinite, and it can be determined that the rectification fault or the starting resistance fault occurs.
2, the test inverter will be the red table rod connected to the P end of the black table rod are connected to U, V, W, DC governor should have dozens of European resistance value, and the resistance value of each phase is the same, the reverse phase should be infinite. The DC governor connects the black watch rod to the N terminal. Repeat the above steps to get the same result. Otherwise, the inverter module fault can be determined.
Dc motor governor dynamic test
After the static test result is normal, the dynamic test can be carried out, that is, the power test machine. Note the following before and after power-on:
1. Before powering on, it is necessary to confirm whether the input voltage is incorrect. If the 380V power supply is connected to the 220V frequency converter, there will be a blast machine (blast capacitor, varistor, module, etc.).
2. Check whether the connecting port of the DC governor has been correctly connected and whether there is any loose connection abnormality. Sometimes, the frequency converter may be faulty and the machine will explode.
3. After power-on, detect the fault display content and determine the fault and cause initially.
4. If no fault is displayed, first check whether the parameters are abnormal and restore the parameters. Start the frequency converter and test the U, V and W three-phase output voltage under no-load (no motor) condition. If there is a lack of phase, three-phase unbalance and other conditions, the module or driving board is faulty
5, in the output voltage is normal (without phase, three-phase balance), with load test. When testing, it is best to test at full load.
Fault judgment
1. The rectifier module is damaged
It is usually caused by grid voltage or internal short circuit. In the case of eliminating internal short circuit, replace the rectifier bridge. When dealing with faults at the site, it should focus on checking the user's power grid, such as the power grid voltage, whether there are electric welders and other equipment that pollute the power grid, etc.
2. The inverter module is damaged
Generally due to motor or cable damage and drive circuit failure. After repairing the driving circuit, replace the module when the driving waveform is in good condition. After replacing the driver plate in field service, care must also be taken to check the motor and connecting cables. Run the inverter after confirming that there is no fault.
3. No display is displayed during power-on
Generally due to switching power supply damage or soft charging circuit damage caused by DC circuit no DC, such as starting resistance damage, it may also be panel damage.
4. Display overvoltage or undervoltage after power-on
Generally due to input phase, circuit aging and circuit board caused by damp. Find out the voltage detection circuit and detection point, replace the damaged device.
5. Overcurrent or ground short circuit is displayed after power-on
Generally due to current detection circuit damage. Such as hall components, operational amplifier, etc.
6. Startup display overcurrent
Generally, it is caused by the damage of the driving circuit or the inverter module.
7, no-load output voltage after normal load display overload or overcurrent
This situation is usually caused by improper parameter setting or damage to the aging module of the driving circuit.
