{"id":15575,"date":"2026-01-06T13:40:47","date_gmt":"2026-01-06T05:40:47","guid":{"rendered":"http:\/\/www.erun-tech.com\/?post_type=dt_portfolio&p=15575"},"modified":"2026-01-06T13:40:47","modified_gmt":"2026-01-06T05:40:47","slug":"chuanbo-440v-donglidianwangjueyuanguzhangchazhaoshixunladianfayubengpupaicha-sop","status":"publish","type":"dt_portfolio","link":"http:\/\/www.erun-tech.com\/en\/project\/chuanbo-440v-donglidianwangjueyuanguzhangchazhaoshixunladianfayubengpupaicha-sop","title":{"rendered":"Ship 440V Power Grid Insulation Fault Finding Practical Training: Pull Method & Pumping SOP"},"content":{"rendered":"
\n
\n

Ship Power Grid Insulation Fault Finding Practical Training Operation<\/h1>\n
440V\/380V Power System Practical Procedures<\/div>\n<\/div>\n
\n

I. Operational content<\/h2>\n
\n
\n
(1) Analog operation of power grid insulation low alarms<\/div>\n
(2) Correct operation of the pull-power search method<\/div>\n
(3) Testing grid insulation with a hand-operated megohmmeter<\/div>\n
(4) Simulated start-up of emergency generator sets<\/div>\n<\/div>\n<\/div>\n<\/section>\n
\n

II. Core practical steps<\/h2>\n
\n
\n

Indicator requirements:<\/strong>The insulation value of the ship's power grid and electrical equipment shallNot less than 1 M\u03a9<\/strong>. Once the hull insulation resistance has dropped to one volt per volt of supply voltage 100 \u03a9<\/strong> Below this level (e.g. 44 k\u03a9 for a 440 V network), the audible and visual alarm must be triggered.<\/p>\n<\/div>\n

\n
1<\/span><\/p>\n
Initial Disposition:<\/strong>Answer alarms, silencing, and flashing. Observe that the switchboard megohmmeter reads less than 1 M\u03a9.<\/div>\n<\/div>\n
2<\/span><\/p>\n
The essentials of the pull-power search method:<\/strong><\/p>\n
    \n
  • Disconnect the power switch one by one and observe the megohmmeter; if the insulation is restored in one of the disconnected paths, the control equipment in that path is faulty.<\/li>\n
  • After confirming the faulty line, cut off the power supply to that line.<\/li>\n
  • Use a hand-operated megohmmeter at the distribution board to measure branch circuit-to-ground conditions one by one.<\/li>\n
  • Isolate the faulty branch, close the remaining switches, and restore power to the non-faulty equipment.<\/li>\n<\/ul>\n<\/div>\n<\/div>\n
    3<\/span><\/p>\n
    Hand-operated megohmmeter to confirm (120 r\/min):<\/strong><\/p>\n

    \u25cf Open circuit test:<\/strong>Meter pen open, pointer points to \u201c\u221e<\/strong>\u201d\u3002<\/p>\n

    \u25cf Short circuit test:<\/strong>Meter pen shorted (light turn), pointer points to \u201c0<\/strong>\u201d\u3002<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/section>\n

    \n

    III. Power system fault finding (No. 1 sea water pump practical training case)<\/h2>\n
    \n
    \n
    \n

    Fault Setting:<\/strong>50 k\u03a9 resistance between phase B of the first seawater pump and the hull.<\/p>\n

    Alarm phenomenon:<\/p>\n

    \u201cAC 440V BUS LOW INSUL.\u201d lamp flashes and buzzer alarms.<\/p>\n<\/div>\n

    \n

    Failure Analysis:<\/strong>Indicates low power grid insulation. The megohmmeter indicates approximately 0.05 M\u03a9, and phase B of the ground lamp is dimmed.<\/p>\n<\/div>\n<\/div>\n

    \n
    Standardized process for power equipment troubleshooting<\/div>\n
    \n
    STEP 1<\/span>
    \nMute the sound and flash to confirm the alarm. Initial lockout of phase B fault by megohmmeter with ground gas light.<\/div>\n
    Key!<\/span>
    \nImportant pumping operations:<\/strong>The standby unit must be started first to replace the currently operating unit, and direct shutdown is strictly prohibited!<\/div>\n
    STEP 2<\/span>
    \nStop each pump and ventilator in turn. Observe the megohmmeter: when the insulation of a motor is restored by stopping it, the faulty machine is locked.<\/div>\n
    STEP 3<\/span>
    \nFaulty equipment is shut down and de-energized for targeted treatment to improve insulation (e.g., drying, cleaning).<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/section>\n