PZ No. 4. Calculation of equipment maintenance schedule.
Task No. 1. Pump operating time between major repairs– 8640 hours, average – 2160 hours, current – 720 hours. The actual number of days of work per year is 360. The number of work shifts is 3, the duration of the shift is 8 hours. By the beginning of the year, the equipment had a mileage after major repairs of 7320 hours, average - 840 hours, current - 120 hours. Draw up a pump maintenance schedule for a year.
Solution.
To draw up a pump maintenance schedule for a year:
1. Number of working days in a month: 360 / 12 = 30 days
2. Month of shutdown for repairs:
Capital (8640 – 7320) / 3 * 8 * 30 = 1.8 months, take February.
Current (2160 – 840) / 3 * 8 * 30 = 1.8 months, take February
RTO (720 – 120) / 3 * 8 * 30 = 0.8 months, we take January.
3. Determine how many months later it is necessary to carry out subsequent repairs:
Capital 8640 / 3 * 8 * 30 = 12 months, we take 12 months, i.e. next year;
Current 2160 / 720 = 3 months, we accept after 3 months, those in February, May, August, November.
RTO 720 / 720 = 1 month, accepted after 1 month, i.e. every month except February, May, August and November.
4. We draw up a PPR schedule for the pump:
Month: Jan. Feb. Mar Apr May June July Aug Sep. Oct. Nov. Dec
View TO TO TO TO TO TO TO TO TO TO
repairs
Task 2. There are 20 dryers in the polyvinyl chloride resin production workshop. The actual operating time of one dryer per year is 6480 hours, the duration of the cycle between repairs is 8640 hours, from major to current repairs is 4320 hours, between repairs and maintenance is 864 hours. The calendar operating time of the equipment per year is 8640 hours. Determine number of overhauls, routine repairs and maintenance of dryers per year.
Methodical instructions.
The required number of repairs per year for each type and type of equipment is determined by the formula:
n repair = Ood.ob. * Tfact * n in. repair / Shopping center, where
Ood.ob. – the number of units of the same type of equipment in operation;
Tts – duration of the overhaul cycle, hour;
Tfact – actual operating time of the equipment, hour;
n in. rem. – the number of all repairs (major, medium, current) of the overhaul cycle.
The number of repairs of each type is determined by the formulas:
capital
n cap. = Tk / Tts
current
n avg. = Tk / Tts.t. - 1
repair and maintenance services
n pto = Tc / Tc.t. - ∑ (drip + current), where
Тк – calendar operating time of the equipment, hour.
Tts.t. – duration of the overhaul period from major to current repairs, hour;
∑ (overhaul + current..) – the sum of capital and current repairs.
Task 3. Calculate the number of compressor repairs based on the following data: number of compressors - 8, duration of the cycle between repairs = 8640 hours, period between overhauls - 7130 hours, between current ones - 2160 hours, between technical repairs - 720 hours. Actual number of days of work per year – 358, number of shifts – 3, shift duration – 8 hours.
Methodical instructions.
To complete the task, use the calculation formulas given in the guidelines for task 2.
Task 4. Draw up a equipment maintenance schedule based on the data given below:
|
Indicators |
Option 1 |
Option 2 |
Option 3 |
|
Equipment |
Compressor |
Dryer |
Autoclave |
|
Operating time between repairs, hours |
|||
|
Capital |
7130 |
14700 |
8238 |
|
Current |
2160 |
2880 |
2880 |
|
RTO |
|||
|
Actual number of working days per year |
|||
|
Number of shifts |
|||
|
Cont. working day, hour |
|||
|
Cont. mileage after repair by the beginning of the year, h. |
|||
|
Capital |
5310 |
12200 |
7310 |
|
Current |
1950 |
||
|
RTO |
Methodical instructions.
To complete the task, use the calculation formulas given in the guidelines for task 1.
Task 5. Determine the equipment downtime for repairs using the data below:
|
Indicators |
Pump |
Bake |
|
|
Labor intensity of repairs, person-hours |
|||
|
number |
|||
|
riggers |
|||
|
locksmiths |
|||
|
welders |
|||
|
Working hours |
|||
|
Number of shifts |
Guidelines
Downtime is equal to the quotient of the division: the numerator is the labor intensity of the repair, the denominator is the product of the number of repairmen by the length of the working day and the rate of completion of the norm.
5. FORMS OF REPAIR DOCUMENTATION
5.1. The repair documentation of this Handbook is maximally unified with the documentation of the industry “Systems for maintenance and repair of power equipment.” The maintenance of the following forms of repair documentation is provided (forms 1-19):
a shift log of identified defects and work to eliminate them; repair log; list of defects; cost estimate;
certificate of delivery for major repairs;
certificate of release from major repairs;
annual preventive maintenance schedule;
monthly plan-schedule-report of PPR or monthly repair report;
statement of annual repair costs;
act for changing the calendar period of repairs;
shutdown schedule;
log of installation and removal of plugs;
act of acceptance of work after shutdown repairs;
passport of power equipment;
nomenclature of the main equipment of the workshop;
range of auxiliary equipment;
work permit for repair work;
production permit earthworks in the territory.
5.2. Changes and additions to previously existing forms of repair documentation were made based on the results of testing the “Unified Regulations on Scheduled Preventive Maintenance of Equipment” industrial enterprises Russia" (Order of the Ministry of Industry and Science of Russia dated May 29, 2003 05.900 114–108).
5.3. The main document by which equipment repairs are carried out is the annual repair schedule (Form 7), on the basis of which the need for repair personnel, materials, spare parts, and purchased components is determined. It includes each unit of equipment subject to major repairs. The basis for drawing up the annual schedule is the standards for the frequency of equipment repairs given in this Handbook.
5.4. In order to link the timing of repairs of power equipment with technological equipment the annual schedule is agreed upon with the enterprise's management department. If it is necessary to use the services of the chief instrument technician, the planned repair periods are agreed upon with the OCP. Repair timeframes for major equipment limiting completion production program, are agreed upon with the planning department of the enterprise.
5.5. In columns 11–22 of the annual schedule (form 7), each of which corresponds to one month, symbol in the form of a fraction it is indicated: in the numerator - the planned type of repair (K - capital, T - current), in the denominator - the duration of downtime in hours. Notes on the actual completion of repairs in these columns are made by coloring the planned numbers with a colored pencil.
In columns 23 and 24, respectively, the annual equipment downtime for repairs and the annual working time fund are recorded.
5.6. The operational document for equipment repair is a monthly plan-schedule-report, approved by the chief power engineer of the enterprise for each energy department and section (Form 8). It is allowed to maintain a monthly repair report (Form 8A) instead of a monthly plan-schedule-report.
5.7. In this case, monthly repair planning is carried out in accordance with the annual repair schedule.
5.8. In columns 7-37 (Form 8), each of which corresponds to one day of the month, the symbol in the form of a fraction indicates: in the numerator - the type of repair (K - capital, T - current), in the denominator - its duration (current - in hours , capital – in days).
5.9. A note on the actual completion of repairs is made after their completion by a specially appointed responsible person in the OGE, in production workshops- workshop foreman.
5.10. The logbook for the installation and removal of plugs (Form 14) is kept by the deputy head of the energy department (head of department, installation, shift supervisor).
5.11. Explanations on the procedure for maintaining other repair documentation are given above in the relevant sections.
5.12. The repair documentation forms given in this section are typical. Depending on the specifics of accounting for ongoing repair and maintenance activities that are not regulated by this Handbook (repair inspections, checks, tests, etc.) in the repair services of enterprises, additional columns (items) may be included in the repair documentation forms.
Form 1
Form 2
Form 3
Form 4
Form 5
Form 6
Form 7
Form 8
Form 8A
Form 9
Form 10
Form 11
Form 12
Form 13
Form 14
How to draw up an annual maintenance schedule for electrical equipment? I will try to answer this question in detail in today’s post.
It's no secret that the main document by which electrical equipment is repaired is the annual schedule of preventive maintenance of electrical equipment, on the basis of which the need for repair personnel, materials, spare parts, and components is determined. It includes each unit subject to major and routine repairs of electrical equipment.
To draw up an annual preventive maintenance schedule (preventive maintenance schedule) for electrical equipment, we will need standards for the frequency of equipment repairs. This data can be found in the manufacturer’s passport data for electrical equipment, if the plant specifically regulates this, or use the reference book “System for Maintenance and Repair of Power Equipment.” I use the A.I. reference book. FMD 2008, therefore, further I will refer to this source.
Download the reference book A.I. Foot and mouth disease
So. Your household has a certain amount of energy equipment. All this equipment must be included in the maintenance schedule. But first a little general information, what is the annual PPR schedule.
Column 1 indicates the name of the equipment, as a rule, brief and clear information about the equipment, for example, name and type, power, manufacturer, etc. Column 2 – number according to the scheme (inventory number). I often use numbers from electrical single-line diagrams or process diagrams. Columns 3-5 indicate service life standards between major repairs and current ones. Columns 6-10 indicate the dates of the last major and current repairs. In columns 11-22, each of which corresponds to one month, the symbol indicates: K - capital, T - current. In columns 23 and 24, respectively, the annual equipment downtime for repairs and the annual working time fund are recorded. Now that we've looked at general provisions about the PPR schedule, let’s look at a specific example. Let's assume that in our electrical facilities, in building 541, we have: 1) a three-phase two-winding oil transformer (T-1 according to the diagram) 6/0.4 kV, 1000 kVA; 2) pump electric motor, asynchronous (designation according to scheme N-1), Рн=125 kW;
Step 1. We enter our equipment into the empty PPR schedule form.
Step 2. At this stage, we determine the resource standards between repairs and downtime:
a) For our transformer: open the reference book p. 205 and in the table “Standards for the frequency, duration and labor intensity of repairs of transformers and complete substations” we find a description of the equipment that is suitable for our transformer. For our power of 1000 kVA, we select the values of the frequency of repairs and downtime during major and current repairs, and write them down in our schedule.
b) For an electric motor according to the same scheme - page 151 Table 7.1 (see figure).
We transfer the found standards in the tables to our PPR schedule
Step 3. For the selected electrical equipment, we need to decide on the number and type of repairs in the coming year. To do this, we need to determine the dates of the last repairs - major and current. Let's say we are making a schedule for 2011. The equipment is operational, we know the dates of repairs. For T-1, a major overhaul was carried out in January 2005, the current one in January 2008. For the N-1 pump motor, the major one is September 2009, the current one is March 2010. We enter this data into the chart.
We determine when and what types of repairs the T-1 transformer will undergo in 2011. As we know there are 8640 hours in a year. We take the found service life standard between major repairs for the T-1 transformer, 103680 hours, and divide it by the number of hours in a year, 8640 hours. We calculate 103680/8640 = 12 years. Thus, the next major overhaul should be carried out 12 years after the last major overhaul, and since the last one was in January 2005, which means the next one is planned for January 2017. For current repairs, the operating principle is the same: 25920/8640 = 3 years. The last current repair was carried out in January 2008, so 2008+3=2011. The next routine repair is in January 2011, it is for this year that we draw up a schedule, therefore, in column 8 (January) for the T-1 transformer we enter “T”.
For the electric motor we get; major repairs are carried out every 6 years and are planned for September 2015. The current one is carried out 2 times a year (every 6 months) and, according to the latest current repairs, we plan for March and September 2011. Important note: if the electrical equipment is newly installed, then all types of repairs, as a rule, “dance” from the date of commissioning of the equipment.
Our graph looks like this:
Step 4. We determine the annual downtime for repairs. For a transformer it will be equal to 8 hours, because In 2011, we planned one routine repair, and in the resource standards for routine repairs the denominator is 8 hours. For the N-1 electric motor, there will be two routine repairs in 2011; the standard downtime for routine repairs is 10 hours. We multiply 10 hours by 2 and get annual downtime equal to 20 hours. In the annual working time column, we indicate the number of hours that this equipment will be in operation minus downtime for repairs. We get the final look of our graph.
Important note: at some enterprises, power engineers in their annual production schedules, instead of the last two columns of annual downtime and annual capital, indicate only one column - “Labor intensity, man*hour”. This labor intensity is calculated by the number of pieces of equipment and the labor intensity standards for one repair. This scheme is convenient when working with contractors performing repair work.
Do not forget that the dates of repairs must be coordinated with the mechanical service and, if necessary, the instrumentation service, as well as with other structural divisions directly related to the repair and maintenance of related equipment.
If you have any questions about drawing up the annual PPR schedule, ask questions, I will try, if possible, to answer them in detail.
Director of CIT Projects and Solutions LLC (Kazan)
In my opinion, at many enterprises there is a certain stagnation in this matter. Namely: the PPR system, inherited from the Soviet period, at one time worked out and debugged, is currently left without development and adaptation to new conditions in most enterprises. This has led to the fact that at enterprises a large proportion of equipment is repaired virtually to the point of failure or emergency shutdown, and the PPR system lives its own separate life and is almost formal in nature - like a habit inherited from the past. The danger of this state of affairs lies in the fact that Negative consequences These situations accumulate gradually and may not be noticeable in a short time interval: an increase in the number of accidents and equipment downtime, increased wear and tear of equipment, increased costs for its repair and maintenance. Many business managers have no idea what significant losses may be hidden here. One of the regulatory documents that determines the implementation of scheduled preventive maintenance is the maintenance schedule.
Speaking about the PPR schedule, one cannot do without a purely symbolic excursion into history. The first mentions of PPR date back to the mid-30s of the last century. From then until the beginning of the 90s, during the Soviet era, an extensive amount of technical documentation was generated, necessary for routine repairs and maintenance of a wide variety of equipment. The PPR schedule, as one of the main documents of the technical service, performed not only an organizational and technical function, but also served as the basis for calculating the financial resources necessary to provide material and labor resources the entire annual and monthly maintenance and repair program.
What's happening now? As our experience and numerous meetings with technical personnel of various enterprises show, in most cases the PPR schedule has lost its original purpose. The process of preparing the annual PPR schedule has in many cases acquired a more symbolic, ritual character. There are several reasons for this situation, both objective and subjective, but all of them are mainly related to the fact that over the past 10-15 years the situation both inside and outside enterprises has changed radically. Let's try to understand some of the reasons for the current situation and offer our vision of how to change the situation for the better.
To begin with, we will describe a typical scheme for preparing a production schedule: what it looks like at many enterprises. By the end of the year, the financial division of the enterprise prepares a draft enterprise budget for the next year and coordinates it with other services. The technical service must prepare its part of the budget, namely: the amount of expenses for materials, components, wages for repair personnel and the services of third-party contractors. The annual maintenance and repair schedule should serve as the basis for preparing the maintenance and repair budget for the next year. However, when preparing the annual PPR schedule for the next year, it is formed virtually without changes on the basis of the current year’s PPR schedule, i.e. the list of equipment, types and list of routine maintenance, as well as their frequency remain without any changes. In turn, the PPR schedule for the current year was obtained in a similar way - based on last year’s. We encountered a situation where such copying was carried out for many years, and the company personnel could not remember the origin of the original source. Of course, some amendments to the budget are still made, but not on the basis of the future PPR schedule, but on the basis of the current year’s budget. As a rule, all changes are limited to adjusting budget amounts for the inflationary component of the cost of materials and work. As for the actual planned dates, list and volume of PPR, these data are practically not adjusted, remaining unchanged from year to year, and they do not take into account the real technical condition equipment, neither the residual life and operating time, nor the history of equipment breakdowns and much more. Thus, the PPR schedule, as a document, performs a formal bureaucratic function and is not a product of engineering calculations.
The next stage - agreeing on the expenditure budget - is a consequence of how this schedule is formed. Namely, at the enterprise, all services related to technical know and understand that the PPR schedule is drawn up “in general” and “enlarged”. Therefore, the budget compiled on its basis can be safely cut: by 10-15%, which, in fact, financial service and does. The technical service, as a rule, is forced to agree. Why? Firstly, justify the presented figures with real statistics technical service cannot: there is simply no data that can be trusted. Secondly, last year financial department I also cut the budget, and got the desired result: money was saved and everything seemed to be fine. “Normal” most often means that the equipment broke down as usual. Thirdly, in the “copied” PPR schedule it will always be possible to find a reserve: something from the PPR will not be carried out or will be completed in a reduced volume, because the schedule is drawn up formally, and local specialists know what exactly can be completed and what cannot be completed not necessary. Let us repeat once again, such a “copied” PPR schedule has no connection with the actually required volume and timing of technical measures. Fourthly, if something suddenly breaks down and production stops, then money will still be allocated for the next urgent purchase, even if it is over the limit. Who will allow production to stand idle?
It turns out that preparing a maintenance schedule and a budget for maintenance and repair costs is more like a formal process, aimed solely at justifying the cost budget for the next year. The primary consumer of this document is the financial department, not the technical staff. And even during the year, the technical service refers to the annual PPR schedule primarily in order to report on expenses for the allocated limits. Is the situation described above due to someone's malicious intent? Hardly. I will give an overview of some of the reasons that led to the described state of affairs.
Regulatory documentation for domestic equipment that remained at enterprises from Soviet times is outdated. Many of the pieces of equipment had exhausted their service life, and the standards provided for them did not take such “excessive wear” into account. And for new domestic equipment, reference books of that time do not take into account that now other components are used in the equipment, often imported production, with other characteristics.
A significant part of the equipment fleet at enterprises is made up of imported equipment, for which there is no documentation. Europe has a very high level of development services, and the lion's share of European enterprises use the services of third-party organizations to service their equipment: as a rule, equipment manufacturers. Our practice has developed in such a way that MRO was traditionally carried out by technical specialists the enterprise itself. Therefore, domestic specialists, accustomed to receiving necessary documentation together with the equipment, they find themselves in a difficult situation: there is no documentation, and they are not ready to use the expensive service of a Western manufacturer.
Another factor that has had a serious impact on the degradation of the SPR technique is due to the fact that in Soviet time in conditions of mass serial production of consumer and industrial goods, manufacturers were provided with mass-produced equipment. Therefore, it was technically and organizationally much easier to create and update standards for mass-produced equipment under centralized planning conditions than at present. This was done by industry institutes, many of which no longer exist.
The next reason is that production capacity domestic enterprises assumed a constant and uniform load of equipment. Maintenance standards were also developed for such production. Namely, a rhythmically operating machine or line is guaranteed to work through a clearly established calendar period its engine hours necessary for carrying out the next maintenance, maintenance-1, etc. Now the situation is completely different: the equipment is loaded unevenly. Therefore, with a calendar approach, maintenance work is very often carried out either obviously earlier than the standard operating time, or with a serious “overrun”. In the first case, costs increase, and in the second, equipment reliability decreases.
It should also be noted that the standards developed in the 60-80s were redundant and included a serious safety stock. Such insurance was associated with the very methodology for developing standards - this is, firstly, and secondly, at that time diagnostic tools were not as developed and accessible as they are now. Therefore, one of the few criteria for planning routine maintenance was the calendar period.
What is the future of the PPR schedule? What to do: leave everything as it is or try to get an effective management tool? Each company decides for itself. I am sure that most experts will agree with me: only a “live” PPR schedule will allow an enterprise to competently plan and economically spend funds from the enterprise’s budget. Obtaining such a maintenance schedule is impossible without the transition of the maintenance and repair system to modern management methods, which include the implementation automated system management necessary for storing, processing and analyzing data on the condition of equipment, and using modern methods preventive diagnostics of equipment, for example: thermography, vibration diagnostics, etc. Only with the help of this combination of methods (automatic maintenance and repair control system and diagnostics) is it possible to increase the reliability of equipment, as well as significantly reduce the number of emergency stops and technically justify the reduction of costs for equipment maintenance and servicing. How exactly, in practice, the introduction of modern MRO methods eliminates the pressing issues and problems identified in this article - I will share these thoughts in the second part of the article. If you, Dear Reader, have comments or additions to this article, write, I’m ready to discuss!
Goal: learn to calculate the frequency of scheduled maintenance and repair work. Draw up an annual plan - equipment maintenance schedule.
Progress:
1.
Select equipment number by option (see Appendix 1)
2.
We enter our equipment into the empty PPR schedule form.
3.
At this stage, we determine the resource standards between repairs and downtime:
4.
We look at Appendix No. 1 “Standards for the frequency, duration and labor intensity of repairs”, select the values of the frequency of repairs and downtime during major and current repairs, and write them down in your schedule.
5.
For the selected equipment, we need to decide on the number and type of repairs in the coming year. To do this, we need to determine the number of hours of equipment worked (the calculation is conditionally carried out from January) (see Appendix 2)
6.
4. Determine the annual downtime for repairs
7.
In the annual working time column, we indicate the number of hours that this equipment will be in operation minus downtime for repairs.
8.
Draw a conclusion
Table 1 – Assignment
|
Option |
Equipment number |
||||
Theoretical part
Scheduled preventive maintenance (PPR) is a set of organizational and technical measures for supervision, maintenance and all types of repairs, which are carried out periodically according to a pre-drawn up plan.
Thanks to this, premature wear of equipment is prevented, accidents are eliminated and prevented, and fire protection systems are maintained in constant operational readiness.
The preventive maintenance system includes the following types technical repair and services:
weekly maintenance,
monthly maintenance,
annual scheduled maintenance,
Annual scheduled maintenance is carried out in accordance with the annual equipment maintenance schedule.
Drawing up a PPR schedule
An annual schedule of preventative maintenance, on the basis of which the need for repair personnel, materials, spare parts, and components is determined. It includes every unit subject to major and current repairs.
To draw up an annual schedule of preventive maintenance (PPR schedule), we will need standards for the frequency of equipment repairs. This data can be found in the manufacturer’s passport data, if the plant specifically regulates this, or use the “Maintenance and Repair System” reference book.
There is some equipment available. All this equipment must be included in the maintenance schedule.
Column 1 indicates the name of the equipment, as a rule, brief and understandable information about the equipment.
Column 2 – number of equipment
Column 3-4 indicates service life standards between major repairs and current ones. (See Appendix 2)
Columns 5-6 – labor intensity of one repair (see Table 2 Appendix 3) based on the list of defects.
In columns 7-8 - the dates of the last major and current repairs are indicated (we conventionally accept the month of January of the current year)
In columns 9-20, each of which corresponds to one month, the symbol indicates the type of planned repair: K - capital, T - current.
In columns 21 and 22, respectively, the annual equipment downtime for repairs and the annual working time fund are recorded.
The annual schedule of preventive maintenance of equipment can be downloaded here.
Annex 1
STANDARDS FOR THE FREQUENCY, DURATION AND LABOR-INTENSITY OF MAINTENANCE AND REPAIR
|
No. |
Name of equipment |
Lifetime standards between repairs |
Equipment downtime |
||
|
Overhead crane Q=3.2t |
|||||
|
Sheet bending machine IV 2144 |
|||||
|
Zigmashina IV 2716 |
|||||
|
Crank shears N3118 |
|||||
|
Welding transformer |
|||||
|
Zigmashina VM S76V |
|||||
|
Overhead crane Q=1t |
|||||
|
Straightener for arc welding VDU - 506С |
|||||
|
Semi-automatic welding machine |
|||||
|
Overhead crane Q=3.2t |
|||||
|
Turning - screw cutting machine 1M63 |
|||||
|
Screw-cutting lathe 16K20 |
|||||
|
Vertical milling machine 6M13P |
|||||
Appendix 2
|
Equipment operating time recording |
||||||||||||||
|
Name of equipment |
Month of the year |
|||||||||||||
|
September |
||||||||||||||
|
Overhead crane Q=3.2t |
||||||||||||||
|
Screw-cutting lathe 1M63 |
||||||||||||||
|
Screw-cutting lathe 16K20 |
||||||||||||||
|
Sheet bending machine IV 2144 |
||||||||||||||
|
Combined press scissors NB 5221B |
||||||||||||||
|
Zigmashina IV 2716 |
||||||||||||||
|
Crank shears N3118 |
||||||||||||||
|
Welding transformer |
||||||||||||||
|
Three-roll sheet bending machine IB 2216 |
||||||||||||||
|
Finishing and boring vertical machine 2733P |
||||||||||||||
|
Zigmashina VM S76V |
||||||||||||||
|
Welding transformer TDM 401-U2 |
||||||||||||||
|
Rectifier for arc welding VDU - 506С |
||||||||||||||
|
Overhead crane Q=1t |
||||||||||||||
|
Vertical milling machine 6M13P |
||||||||||||||
|
Rectifier for arc welding VDU - 506С |
||||||||||||||
|
Vertical drilling machine GS2112 |
||||||||||||||
|
Vertical milling machine 6M13P |
||||||||||||||
|
Semi-automatic welding machine |
||||||||||||||
|
Overhead crane Q=3.2t |
||||||||||||||
|
Screw-cutting lathe 1M63 |
||||||||||||||
|
Screw-cutting lathe 16K20 |
||||||||||||||
|
Vertical milling machine 6M13P |
||||||||||||||
Loading...