求翻译：电机对地绝缘为0.5 MΩ，原因是电缆引线绝缘皮老化，要更换电缆引线重新连接、并更换电缆密封；是什么意思？

Electrical insulation for 0.5 MΩ because cable insulation ageing of the skin of the leader, to replace the reconnect the cable inlets, and replace the cable seal;