High-voltage motors’ voltage level is usually as high as 6kv or 10kv, so the insulation of the cable in the junction box of the motor’s main power is very important. The motor’s connection cable is divided into two parts, one is the outlet cable of the motor’s stator and the other part is the power supplying cable while the motor is running. As provided in the national standard GB14711-2006 “ Security requirements of small and medium-sized rotary motors”, for the motor with 6kv rated voltage, the smallest electrical clearance of the different charged parts in the junction box is 50mm, while the smallest creepage distance is 80mm; for the motor with 10kv rated voltage, the smallest electrical clearance of the different charged parts in the junction box is 90mm, while the smallest creepage distance is 160mm. To 

    In order to ensure the smallest electrical clearance and the smallest creepage distance in the junction box to meet the national standards, the majority of the domestic high-voltage motors’ manufacturers use insulated terminals to actualize the insulation. Connection bolts made of copper are welded to the end of the outlet cable of the motor’s stator, and are set in the insulated terminals made of ceramic or DMC.    The outlet cable of the motor’s stator and the power supply cable are connected by bolts. In this structure, if the two kind of bolts are connected by bolts, the power supply cables may become skew, so it is hard to ensure the smallest electrical clearance and the smallest creepage distance of the two bare charged bodies. The motor may be burned because of short circuit caused by charged bodies discharging. At the same time, in this connection method, the need for welding cable bolts makes the efficiency low.

    The technology program being used in our company: at the bottom of the junction box installed a outlet plate made of epoxy glass cloth plate 3240. Drill Φ30 diameter holes on the outlet plate according to the number of the outlet cable, thread the stator’s outlet cable from the three holes, and hitch the cable with pressurized ring made of latex. Then jam-pack the clearance of the outlet role which can also protect the stator’s outlet cable. There are two Φ14 diameter installation holes drilled under the outlet cable, which is used to install clamps made of glass cloth plate 3240. The clamps are used to fix 3 stator’s outlet cable. At the end of every stator’s outlet cable installed a connection head, which is connected to the cable by cold-pressing process. When the power supply cable is working, the power supply cable and the stator’s outlet cable are connected by bolts, and after connected they should be bind up with high-voltage insulation adhesive plaster. Simultaneity, the length of the outlet cable can be adjusted, so the drawbacks that the power supply cable’s length is inappropriate can be avoided.

    Beneficial effects: All charged cables are insulation and there are no bare charged bodies, which can ensure that there are no discharging phenomenon cause by the motor’s charged cables, so we can make sure of the safe running of the motor; besides, the installation is easy, the efficiency is high, and there are few components.

    At present, this new method of the motor’s outlet under high-voltage invented by my company has declared the patent.