DC governor fault repair

The main motor of the DC speed control system is a closed-loop control system, as shown earlier in the DC speed control system, the concept of the device system, not only refers to the Siemens DC device itself, but also includes the DC motor, speed measuring machine, protective elements and components involved in closed-loop control. First monitor the Siemens DC governor operating panel display, and then according to the manual shows the fault and fault part, analyze and troubleshooting; if you can not find the fault location, you can use a laptop computer or handheld programmer to monitor the main motor starter relay; in addition, PLC program common faults are external 23Q1 lubrication pumps, 3B1 main motor speed centrifugal switch, 3k4 flywheel brake open Detection limit, 3Q5 flywheel brake open control valve; these external perishable faults are easy to check, but also can not start and stop the main motor of the press frequently; maintenance experience has proved that if the failure point is one of them, you can quickly find the fault location and repair of Siemens DC governor.

If it is found that 3A4K1 (DC device system fault relay) first power loss caused by 3K8 power loss, so that the main motor can not start or stop, you should check the "DC device system". Check air switches and fuses (for the main motor not starting), DC motors, speed measuring machines and protection components involved in closed-loop control in accordance with the instructions on the operating panel of the device. If there are no problems, check the Siemens DC device itself, such as thyristors, electronic boards, and connectors that trigger the thyristor trigger signal. When it is determined that there is a problem with the Siemens DC governor itself, do not dismantle the board easily, but cooperate with the relevant departments in time. In addition, there are many reasons for failure, such as loose terminals, you need to find the right way to Siemens DC governor repair operation, so as not to cause damage to the machine.

Siemens DC governor repair process:

1. Power-on detection found that one SCR trigger pole is disconnected, the other SCR trigger pole is normal. After replacement, all trigger signals are normal (one of the waveform is abnormal).

2. Siemens general failure, and no-load speed instability also exists, the actual measurement of three-phase current balance.

3. Siemens 6RA70 was shipped back to the company for testing. The current and voltage waveforms were incorrectly detected with DriverMonitor. Restore the factory settings, re-enter the parameters, drive 0.55KW small motor normal operation, no speed instability phenomenon, running strong.