modification of boiler water circulating pump
the 300kw 6kv imported bcp motor is used for the starting of the supercritical machine unit. the normal problem for this type of motor is the abnormally high operation temperature which causes overheat tripping shutdown, sometimes, some even can not pass the 168 hours’ trial. after inspection, the problems of this type of motors are:
1.the capacity of thrust bearing exceeds the limit, the thrust pads (picture 10) and the thrust disc were seriously damaged (picture 11)
2.the internally installed filter was so small that it was easy to be blocked
3.the internal flow road was blocked (picture 12)
4.the terminal gland assembly was easy to crack and the insulation resistance was easy to be reduced due to moisture condensation (picture 13)
after the analysis, the problems above could have much to do with operating environment and insatisfaction of operation conditions. aiming at this problem, the company designed the external magnetic filter (picture 15) to replace the original internal filter. the filtering area is four times as large as the original one, and it can adsorb effectively the ferromagnetic particles in the internal circulating cooling water to reduce the damage to the bearings and windings. the external filter can be cleaned in operation time, which can avoid the shutdown caused by the blocking of the filter. meanwhile, the company also adopted the axial trust balancing technique to reduce the load of thrust bearing and to improve the reliability and extend the life of the bcp.
in the high humidity condition, the insulation resistance of terminal gland assembly of this type of stator winding ( the transition tip) reduces obviously. it is easy to crack and be damaged with poor reliability. the terminal gland assembly which was redesigned and manufactured by our company with complex structure (picture 14) overcomes the defects that have been mentioned above. even when the components of the terminal gland assembly have contact with water, the insulation resistance will never change.