Page 37 - Intro Predictive Maintenance

28 An Introduction to Predictive Maintenance

(-ve)
Increasing consumption
of fuel, spares, etc.
Cash
outflow
Extra cost due to
( ) S
knock-on effect
Steady cost of
fuel, spares, etc.

Plant in good condition Condition deteriorating
0
0
Time/usage (hours)
Figure 2–2 Typical cost of deterioration in plant condition.

(-ve)
Increasing cost as
major components
begin to fail
Cash
outflow
( ) S
Cost of routine ppm

Increasing wear on
moving parts
Plant ‘as new’
0
0
Time/usage (hours)
Figure 2–3 Typical cost of a preventive maintenance strategy.

If CM is to replace planned preventive maintenance, considerable savings may be real-
ized in the spares and labor requirement for the plant, which may be found to be over-
maintained. This is more common than one might expect because maintenance has
always believed that regular prevention is much less costly than a serious breakdown
in service. Unit replacement at weekends or during a stop period is not reflected in
lost production figures, and the cost of stripping and refurbishing the plant is often
lost in the maintenance department’s wage budget for the year. In other words, the
cost of planned preventive maintenance on plant and equipment can be a constant
drain on resources that goes undetected. Accordingly, it should really be made avail-
able for comparison with the cost of monitoring the unit’s condition on a regular basis
and applying corrective measures only when needed.