1. Fault
In mid-August 1999 10:00 One day-night, I Potential Chemical Depot drum cold Section 3 are running a Roots blower 160m3/min (fan models LG-700 × 830-2, equipped with JS128-10, 130kW motor) suddenly occurs, dispensed with Mitsubishi MT-A140E - 132K-type converter Protection stands, then inverter fuselage panel LED Display "E.OC3", namely overcurrent circuit fault. The switch saved operatives will run from fan failure, the opening of another standby fan, coke production back to normal.

2. OMV analysis

The survey of the scene, then the production process parameters pressure, flow rate, all in the normal range, there is no abnormal changes; Fans dispensed with the 130kW motor work load has been a long-term stability, and load rate of only around 70%. The inverter overcurrent protection motion analysis, fault occurred in equipment Fan great possibility. However, the size of the typhoon, heavy quality, it is difficult to accurately pinpoint the trouble spots where what parts. According to previous conventional method requires three to four workshop for the disintegration of the fan inspection, re-assembled after treatment, at least one day this time, wasting time and effort.

According to the existing conditions, envisaged by low-speed drive inverter fan rotation, through the fan may have abnormal sound to determine the type of fault to facilitate much.

We dispensed with in the scene with Mitsubishi inverter voltage from the beginning and gradually increase to 10Hz, 20Hz-then slowly increase, the final only to 30Hz; Slow from 30Hz to 20Hz, 10Hz and below repeatedly. Meanwhile, we carefully observed motor, blower status of the operation, motor abnormalities, but found that the internal fan in low gear box 10 ~ 20Hz frequency operation, a boring internal cyclical abnormal noise. This repeated testing, and to determine quickly discriminant fan gear box with mechanical problems.

3. Fault repair

The workshop opened Gear Cover found in a small iron box, two gears in a gear tooth was milled bad angle, forming an irregular gap flashless plane. Accordingly, the gear box two bite higher speed running gear in the process of being small iron block, in the larger role of rotational inertia of being run over damage caused gear, and inverter overcurrent protection in action stands. The workshop will be damaged gear flashless file-gap after finishing repair, fan quickly resumed production run. Fans from the failure to repair inspection, after just over two hours. Using this method, large fan discriminant inspection equipment failure, in a convenient and time-saving effort.