The document provides an overview of a presentation on maintenance systems. It discusses key topics like machinery failure, maintenance objectives, types of maintenance including breakdown, planned, preventive, and predictive maintenance. It covers maintenance cost analysis, availability calculation, integration of maintenance with other departments. Specific sections describe maintenance departments and roles, engineers' duties, use of computer systems, importance of maintenance records and overhaul management. The document aims to outline important aspects of effective maintenance systems for industrial operations.

1. Maintenance System
A.K.Mohindru
Ex-General Manager
NTPC Ltd.

2. Presentation Overview
 Machinery Failure
 Maintenance Objectives
 Maintenance Types
 Maintenance Cost
 Availability
 Integration of Maintenance
 Maintenance Department
 Engineers Duties
 Efficient Maintenance Service
 Maintenance Records
 Overhaul Management

3. Machinery Failure
 Total damage
 Loss of asset
 Loss of
production
 Loss of life

4. Machinery failure
 Equipment malfunctions have a direct impact on:
 Production capacity
 Production costs
 Product and service quality
 Employee or customer safety
 Customer satisfaction

5. Problems in Maintenance
 Lack of management attention to maintenance
 Little participation by accounting in analyzing and
reporting costs
 Difficulties in applying quantitative analysis
 Difficulties in obtaining time and cost estimates for
maintenance works
 Difficulties in measuring performance

6. Problems Exist Due To:
 Failure to develop written objectives and policy
 Inadequate budgetary control
 Inadequate work quality
 Infrequent use of standards
 To control maintenance work
 Absence of cost reports to aid maintenance planning
and control system

7. Bath Tub Curve
Machinery Failure

8. Mean Time Between Failure (MTBF)Mean Time Between Failure (MTBF)
Frequency of FailureFrequency of Failure
Routine failuresRoutine failures
follow normalfollow normal
distributiondistribution
Machinery failure

9. Maintenance Objectives
1. Increased Availability
2. Maximize useful life of equipment
3. Reducing Cost of production
4. Safety Requirements
5. Customer Satisfaction
Increased Availability at optimum cost with safety

10. Maintenance Types
 Breakdown Maintenance
 Planned Maintenance
 Preventive Maintenance
 Predictive Maintenance

11. Maintenance Types
 Run the equipment till breakdowns
 No services except occasional
lubrication unless failure occurs
 No maintenance men on regular
basis
 Maintenance done by sub-
contractors
Breakdown Maintenance
Increased Down Time Increased costs & Pressures
No organized efforts to find out
reasons
•No stock of spares
•
•No budget
•No records and No Safety
* Initially it looks economical

12. Maintenance Types
In this type of service, the emphasis is placed on the
machines condition
 What does the manufacturer prescribe?
 Is it working under normal load?
 Are the conditions as good as those envisaged by the
manufacturer?
 Do we allow for extra attention owing to corrosion, wear etc
Planned Maintenance
Putting the machine in good condition timely e.g replacement of filter/oil, plant
overhaul based on manufacturer recommendation

13. Maintenance Types
 Instructions are more detailed than in routine
 Schedule is drawn with dates/Hrs
 Need for establishing the work-load for the crew
 Entails considerable planning effort, faithful
implementation
and recording
 Detailed instructions reduce the chance of missing any
activity. Unforeseen work is greatly reduced
Planned Maintenance advantages

14. Maintenance Types
 PM increases reliability
 PM reduces work-load
 PM reduces down time
 PM reduces unplanned work
 PM reduces maintenance cost
Preventive Maintenence

15. Maintenance Types
 System which strives to reduce the likelihood of failures.
 Parts are replaced on time basis that could prevent failure
though the part maybe in good condition
 Locates weak spots of machinery and equipments
 Provides them periodic/scheduled inspections and minor
repairs to reduce the danger of unanticipated breakdowns
 Preventive Maintenance System is more expensive due to
more of planning and replacement of parts
Preventive Maintenance

16. Maintenance Types
Description Week
1 2 3 4 5 6 7 8 9 10 11 12
Check Oil Filter O O O
Replace Oil O
Inspect bearing O
Replace Bearing O
Check liner
condition
O O
Check vibration O O O O
Tighten bolts O O O O
Check Motor
Insulation
O
Check terminals O O
Preventive Maintenance Schedule

17. Maintenance Types
System based on predicting the failure.
 In predictive maintenance, machinery conditions are
periodically monitored and this enables the
maintenance crews to take timely actions, such as
machine adjustment, repair or overhaul
 It makes use of human sense and other sensitive
instruments, such as audio gauge, vibration analyzer,
amplitude meter, pressure, temperature and resistance
strain gauges etc.
 Monitoring the condition of machine and its components
 Planning the maintenance based on deteriorating
condition parts are replaced when life is near to finish
Predictive Maintenance Type ( Condition Monitoring)

18. Maintenance Types
1. Temperature
2. Vibration
3. Cracks
4. Deterioration
5. Voltage/current
6. Performance evaluation
Predictive Maintenance Monitoring Parameters

19. Maintenance Types
 Unusual sounds coming out of a rotating equipment predicts
a trouble
 An excessively hot electric cable predicts a trouble
 Simple hand touch can point out many unusual equipment
conditions and thus predicts a trouble

20. Predictive Maintenance
Condition Monitoring
MaintenanceTypes

21. Condition Monitoring

22. Maintenance Cost
1. Overhead Expanses
2. Labour Cost
3. Spares and Consumables
4. Loss due to down time

23. MaintenanceMaintenance
CommitmentCommitment
CostCost
Breakdown CostBreakdown Cost
Maintenance Cost

24. MaintenanceMaintenance
CommitmentCommitment
CostCost
PM CostPM Cost
Breakdown CostBreakdown Cost
Maintenance Cost

25. MaintenanceMaintenance
CommitmentCommitment
CostCost
PM CostPM Cost
Breakdown CostBreakdown Cost
Total Maintenance CostTotal Maintenance Cost
Maintenance Cost

26. MaintenanceMaintenance
CommitmentCommitment
CostCost
PM CostPM Cost
Total Maintenance CostTotal Maintenance Cost
Breakdown CostBreakdown Cost
OptimalOptimal
Maintenance Cost

27. Maintenance Cost

28. Mean-Time-between-Failures MTBF
MTBF = Total Operating Time = 1
. No Of failures n
Mean-Time-to-Repair, MTTR
MTTR = Total Outage Time = 1
. No Of failures r
Availability = ________Total Operating Time_______
. Total Operating Time + Total Outage Time
Availability

29. Actions For High Availability
Failure Investigation
 Find the cause of break downs
 Analyze it
 Take corrective action in next shut down
 Monitor the performance
Resource Availability
 Keep spares well in advance
 Mobilize work force quickly
 Keep job area ready to work : lighting, scaffolding, power
supply etc

30. Integration of Maintenance
Company
Trial
Spares
Procurement
Maintenance
Dep't
Manpower
Fire & Safety
Availability
Permit to Work
Production
Dep't
Administration

31. Maintenance Departments
 A maintenance manager typically is a plant engineer
who reports to a plant manager
 Maintenance departments are usually split into two
groups:
 Buildings
 Equipment

32. Maintenance Departments
Fitters/Technicians
Engineer
Boiler Maintenance
Supervisor
Foreman
Pressure Parts
Fitters/Technicians
Foreman
Rotating Machines
Riggers
Helpers
Riggers
Helpers
Maintenance Work Force

33. Maintenance Departments
 Repairs often performed on an emergency basis to:
 Minimize interruptions to production
 Correct unsafe working conditions
 Improve product/service quality
 In emergency situations:
 Specialists may work overtime
 Supervisor/engineers are nearby to collaborate
 Standby machines may be quickly put in operation
Repair Crews and Standby Machines

34. Engineers Duties
 Preventive Maintenance Schedule
preparation
 Deliver the work order card with
Quality sheet to Supervisor
 Inspect the work being done as per
quality and safety
 Keep inventory control: procurement, store
 Follow safety guide lines
 Effort for zero breakdown/failures
 Mobilize resources for faster completion of work
 Prepare Reports

35. Computer Assistance in Maintenance
 Scheduling maintenance projects
 Maintenance cost reports by production department,
cost category, and other classifications
 Inventory status reports for maintenance parts and
supplies
 Parts failure data
 Operations analysis studies

36. Efficient maintenance Service
 Ensuring work quality
 Minimum repair time
 Ensuring safety

37. Efficient maintenance Service
1. Developing Quality norms
2. Measurements- stage inspections
3. Corrections
4. Recording/report
Ensuring maintenance work quality

38. Efficient maintenance Service
 Work Order Planning and Control
 Efficient and effective maintenance requires detailed planning of repairs,
plant
 services, overhauls and projects.
This work must be co-ordinated with the requirements of production to have
the minimum effect on the overall production plan.
The maintenance plan should be easily modified to allow for major
emergency work, changes in production methods and improvements in
design.
Maintenance control indices can provide a method of assessing
maintenance activities. Control indices should function as part of the overall
maintenance information system and use dynamic data such as labour
costs, spares usage, and delay costs. Analysis of the data provides
feedback that the manager can use to assess actual performance against a
target, and so monitor the effect of changes in maintenance policy.

39. Efficient maintenance Service
Computerised Maintenance Management System
 A computerised maintenance management system will contain a
number of integrated programs or modules to improve the efficiency
and effectiveness of the maintenance engineering function.
 the system should be easy to use and provide the engineer with all of
the information that is required to make better decisions.
The basic modules or component part of the maintenance systems are :
 Preventive maintenance
 Asset register
 Maintenance stores system
 Purchasing
 Work order planning and control
 Plant history and analysis

40. Efficient maintenance Service
Asset Register
 This is an inventory of all of the plant, equipment and services for
which a manager has responsibility. Repair work that is generated
by the preventive maintenance system will in most cases need to be
planned and prepared.
 This includes technical details, serial numbers, location,
manufacturer etc. and most important a list of the spare parts used
on the machine together with the current stock balance.
 The purpose of the asset register is to centralise this data for use in
planning
 maintenance work.
 In addition to providing rapid access to information, the manager
can be sure that the relevant data is always available and has not
been misplaced.

41. Maintenance Records
 History Record:
 When job is done?
 What activities were done?
 When completed?
 How was the machine performance?
 Planning Sheet:
 When next to be done?
 What resources will be required?
 What will be the duration?

42. Maintenance Records
 Identify the equipments
 Prepare the specs (Number plate details)
Equipment Identification

43. Maintenance Records
 ID Fan1A
 ID Fan 1B
 FD Fan 1A
 FD Fan 1B
 PA Fan 1A
 PA Fan 1B
 Boiler Feed Pump 1A
Equipment Identification

44. Work Instruction
Singrauli Super Thermal Power Station
Equipment: Boiler Feed Pump RPM: 3600 KW 1500 Kw
Scope: Mini Overhauling of Boiler feed Pump Doc No: QSR/039/8
1. Decouple pump from drive turbine or hydro coupling
2. Open the bearing top covers
3. Check bearing conditions
4. Check Thrust collar conditions
5. Check pump centering
6. Check bearing clearances
7. Check pump floats
8. Adjust as per requirements
9. Repair/replace worn out parts
10. Box up bearings
11. Align pump w.r.t drive turbine/hydro coupling
12. Take trial run of pump
13. Refer QSR/039/9/AUX/011 for checks and records
Maintenance Records

45. Maintenance Records
S.N. Decription Measured Value
1. Bearing Condition:
Scratch marks: Nil
Color: No discoloration
Pitting Nil
Fine scrtch marks seen
Bluish color from sides
No pittings
2 Bearing side clearance: 0.020-0.025mm 0.022mm
3 Bearing top clearance: 0.030-0.045mm 0.030 mm
4 Coupling Alignment : < 0.07mm 0.06mm
5 Shaft run out: <0.086 mm 0.089 mm
6 Bearing level 1D < 0.02mm/m 0.011 1D
00
0.5D
Work Protocol

46. Maintenance Records
The Care and maintenance of Pumps
(Describes Standard Maintenance Practice)
1. Objective
2. Operational History
3. Inspection and maintenance
4. Modifications
5. Vibration requirements
6. Bearing Temperature
7. NPSH
8. Pump casing distortion
9. Overspeed test
10. Pump efficiency
Operation Guidance Note

47. Overhaul Management
 Machine needs regular overhaul
 Periodicity is based on experience or on
manufacturers recommendations
 Boiler tubes errosion normally in 2 years
 Burner life is 1 year Boiler Overhaul : every year for 10 days
 Furnace deposition 1 year
 Turbine efficiency drops 0.5%-1% in 5 years
 Turbine blade cracks appear in 5-6 years
 Turbine overhaul : 5years for 45 days

48. Overhaul Management
 Preparation of resources:
 Engineering Declaration: 12 months advance
 Contract: 3 months in advance
 Spares procurement; 12 months advance
 Shut down planning ; rolling plan
 Mobilization
 Pert Chart activitiy listing
 Allocation of executive team to monitor
 Daily work progress meeting
 Overhaul Execution

49. PERT & CPM

50. CPM
What is CPM?
Critical Path Method
What is Critical Path?
CPM is a mathematically based algorithm for scheduling a set of project
activities.

• A list of all activities required to complete the project,

• The dependencies between the activities, and

• The estimate of time (duration) that each activity will take to completion.
The longest time is determined

51. CPM example
Hang a picture on the wall
 Choose a place on the wall
 Buy the screws
 Choose the picture Drill a hole
 Screw in the screws
 Hang the picture

52. The actions “drill a hole,” “screw in the screws” and “hang the picture” form a
sequence of tasks that must be performed in a specific order, one right after the
other, to ensure a successful result. Such tasks are called “sequential” activities

53. CPM
 you cannot start some activities until the
others are finished. These activities need to
be completed in a sequence, with each stage
being more-or-less completed before the next
stage can begin

54. CPM
The critical path consists of the longest
sequence of activities from project start to
end that should be started and completed
exactly as scheduled to ensure the project is
completed by a certain date in the future