When ship electrical equipment is regularly monitored and tested. Then monitoring indicates that a breakdown is imminent, the equipment is repaired or replaced and any other specified maintenance procedures are carried out.
Regular insulation testing and vibration testing are two forms of condition monitoring.
Condition monitoring is also carried out at fixed regular intervals.
The aim is to forestall breakdown by predicting probable failure from the trend shown by the monitoring results.
The advantage of this type of maintenance is that equipment is not subjected to unnecessary maintenance.
Equipment is regularly condition monitored according to a monitoring schedule. Measurements are taken of insulation resistance, temperature
and vibration (of motors). Contacts and other parts subject to deterioration are inspected.
All findings are recorded in an historical record file.
No maintenance is carried out until the trend of test results indicates that it has become necessary.
The equipment is then either replaced, repaired or subjected to a major overhaul, as specified on a job card.
A maintenance records system is required.
The recorded measurements of insulation resistance may show a falling trend, indicating a progressive degradation of insulation.
The equipment should be inspected and repaired before the insulation resistance falls to a dangerously low value.
Hot spot temperatures emitted from live electrical equipment can be monitored from a safe distance using an infrared detector or camera.
The recorded measurements of the vibration of a motor may follow a rising trend, indicating progressive bearing deterioration.
Bearings should be replaced before failure occurs.
Immediate repair or maintenance is probably not necessary but should be put in hand at the earliest convenient moment.