256HC Mast Section Inspection and maintenance of electrical equipment inside tower crane
1、 Inspection of asynchronous motor of tower crane
1. Whether the bolts of each part are fastened and whether the sign of outgoing line is correct. Whether the rotor rotates flexibly.
2. The DC resistance error of tower crane shall not exceed 4% of the average value.
3. The insulation resistance to ground and interphase shall not be less than 5 megohm.
2、 Inspection of explosion-proof switch of tower crane
1. The switch stops and delivers power correctly, with short circuit and reliable overload action.
2. The switch handle and indicating device are in correct position and flexible action under various working conditions.
3. The action relationship between various interlocking, locking, handle and button is clear.
4. The indication of all kinds of indicator lights is consistent with the state of handle and button, and the color is correct.
3、 Inspection of explosion-proof magnetic starter for tower crane
1. Contact system in tower crane: the mating surface of dynamic and static contact shall be clean, without damage, burr, etc.
2. The suction system shall be flexible and the armature and iron core screws shall be fastened. Spring pressure adaptation. The armature and the iron core surface are tight without corrosion. There is no damage to the short circuit ring.
3. Suction coil: the rated voltage on the tower crane shall be consistent with the actual circuit voltage.
4. Use a 500V megger to measure the insulation resistance, and the 660V main circuit shall not be less than 2 megohm. The control circuit shall not be less than 0.5 megohm.
4、 Inspection of starters in electrical equipment on tower crane construction site
1. Vacuum contactor, vacuum isolating switch. The vacuum interrupter is in good condition. Screw fastening, flexible mechanism.
2. Each auxiliary control switch. The button switch is intact.
3. The connector shall be firmly connected. The wiring is in good condition.
4. Power supply voltage and starting voltage class I. And set the leakage and locking plug-ins to the corresponding voltage level.
5. The isolation gap meets the requirements.
6. Measure the insulation resistance with 500 pairs of voltage. The main circuit shall not be less than 5 megohm. The control circuit shall not be less than 0.5 megohm.
