Agriculture:- Model Bankable Projects in India | Minor Irrigation : Pumpsets Part - 2 --- www.nabard.org

Agriculture:- Model Bankable Projects in India

Minor Irrigation : Pumpsets Part 2

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TABLE - V Minimum Efficiency in percentage of Electric Motors for Centrifugal Pumpsets Motor Rating Horizontal Centrifugal Pumps Speed ( 1200 to 2000 RPM ) Speed (2001 to 3600 RPM ) (kw) Single Phase Three Phase Single Phase Three Phase 0.37 56 - 54 - 0.75 66 - 63 - 1.1 70 76 68 73 1.5 72 77 70 74 2.2 - 77.5 - 75 3.7 - 80 - 79 5.5 - 82 - 80 7.5 - 83 - 81 9.3 - 85 - 81.5 11 - 85.5 - 82 15 - 86 - 83 4. The motor should have BIS certification conforming to IS - 7538. 5. The motor which has a maximum efficiency for a given BHP should be selected from a range of BIS marked motors. This criteria should over-ride cost considerations.  6. Motors for which genuine spare parts are easily available should be preferred. 7. Motors for which after sales service is easily available should be preferred. 8. Motors which have a reputation for giving efficient and trouble free service should be preferred. 9. An electric motor should always be provided with a starter and a capacitor matching the motor. In general, for motors upto 3 HP a 1 KVAR capacitor should be used and for motors between 3 to 5 HP a 2 KVAR rating capacitor should be used. Selection of Diesel Engine Where electric power is not available and a diesel engine is required to be used to run an agricultural pumpset, following guidelines should be used in selecting a diesel engine. BHP of the diesel engine should be 10 percent more than the required BHP of the pump. Specific Fuel Consumption (SFC) of the selected diesel engine should be as low as possible and it should not exceed 188 gms/bhp/hour (252 gms/kwh) for diesel engines in RPM range 1000 to 2000 and 210.5 gms/bhp/hour (282 gms/kwh) for diesel engines in RPM above 2000. The SFC is specified in terms of the diesel oil consumed in grams per BHP for one hour operation of engine. The diesel engine should have BIS certification conforming to IS-11170 or IS-7347. The lubricating oil consumption of diesel engine should be about 1 percent by volume of diesel oil consumed. Engines having low lubricating oil consumption should be preferred. Engines for which spare parts are easily available should be preferred. Engines for which after sales service is easily available should be preferred. Engines which have a reputation of giving efficient and trouble free service should be preferred. Selection of Suction and Delivery Pipes Suction and delivery pipes for centrifugal pumpsets are generally of either GI or RPVC. HDPE pipes conforming to IS-4984 can also be used for suction and delivery pipes but are not normally preferred by farmers. The size of the suction and delivery pipes should be such that the friction head loss does not exceed 10 percent of the equivalent length of piping system upto the delivery point. The size of pipes on the suction and delivery side should be equal. The pipes should be BIS marked conforming to IS-1239 (for GI pipes) and IS-4985 or IS- 12231 (for RPVC pipes). Although the size of the suction and delivery pipes should be estimated from BIS Tables for each individual case, the following table gives general guidelines for selection of G.I. and RPVC pipes as per BIS standard. If the delivery offset distance is more than 3 m, then larger pipe size may be used to reduce friction losses. TABLE VI Size of Suction and Delivery Pipes for Centrifugal Pumpsets Discharge (lps) Pipe Size (mm) (Both Suction and Delivery Pipes) Medium Grade GI Pipe (C = 140) RPVC Pipe (C = 150) Nominal Pipe Size Inside Dia Nominal Pipe Size Inside Dia 2 40 41.85 40 36.8 4 50 52.95 63 58.1 6 65 68.65 63 58.1 8 65 68.65 75 69.3 10 80 80.65 75 69.3 12 80 80.65 90 83.2 14 80 80.65 90 83.2 16 100 105.05 90 83.2 18 100 105.05 110 102 20 100 105.05 110 102 22 100 105.05 110 102 24 100 105.05 110 102 26 100 105.05 110 102 28 100 105.05 110 102 GI = Galvanised Iron RPVC = Rigid Poly-Vinyl Chloride C = Coefficient of friction. Generally pipes are selected as per normal pipe size as given in the table. Selection of Foot Valve The size of the foot valve shall be equal to the size of the suction pipe. Only BIS marked foot valves should be selected conforming to IS -10805. The open area of the foot valve for entry of water should be about 2.5 times the cross sectional area of the suction pipe to which it is attached Farmers' Guide for Selection of Agricultural Pumpset Detailed method of pumpset selection necessarily requires a certain minimum expertise both with respect to hydrogeology of the area and other hydraulic aspects for selection of pump, motor and accessories. It has generally been observed that even the minimum technical guidance required for selecting a proper pumpset and its accessories is at present not available to farmers. Therefore, to assist the farmers and field staff a Matrix for selection of pumpset is given in Annexure I and II which would serve as a ready reckoner. This matrix gives the diameter of suction and delivery pipes and the BHP of motor under various conditions of total head and discharge. The total head includes the static suction and delivery head, friction loss in pipes and other accessories and variation in head due to lowered water level during the operation of the pump. Besides, in the matrix the nominal pump input has been increased by 10 percent to take care of tolerance on pump efficiency and variation in duty conditions. Further, minimum motor efficiency has also been considered in accordance with the motor ratings. Parameters given in the matrix may not have general applicability under all conditions but these would be useful in selecting proper size of pumpset and its accessories. The size of pipes and BHP of electric motor or diesel engine should be selected so as to be nearest to those indicated in the matrix depending upon their market availability. FINANCING OF AGRICULTURAL PUMPSET AS PER IS-10804 (1994) Financing of agricultural pumpsets involves, interalia, proper selection of different components of pumpset like electric motor or diesel engine, pump, foot valve, suction and delivery pipe, bends and joints etc. To ensure that each of these components is of good quality and efficient, BIS has brought out a Complete Pumping System Standard for selection of agricultural pumpset and is covered under IS-10804 (1994) which gives selection standards for each component. The dealer or supplier of the pumpset is expected to guide and assist farmer in proper selection and installation of pumpset depending on season wise water levels and discharge from the well, cropping pattern and area under different crops and method of irrigation. It is always advantageous to select a Monobloc Pumpset than a Coupled one. National Bank's circular in regard to adherence of BIS-10804 by banks while financing for pumpset is given in Annexure III. Cost of Pumping System Cost of pumping system is decided by the type of pumpset i.e., electric motor or diesel engine, Horse Power of pumpset, diameter and length of suction and delivery pipes and other accessories. Centrifugal pumpset of 3-7.5 HP are adequate for normal irrigation conditions. To help farmers to receive the pumping system at site and to utilise the services of the dealers, supplier or the village mechanic for proper selection of the pumpset on the well, cost of transport and installation could also be included in the total cost of the pumping system for the purpose of bank loan. Cost of pumping system varies with make and brand name. The farmer is free to select any BIS marked pumpset as per IS-10804 (1994) out of the various brands and makes available in the market. Cost of pumping system also changes with time and has to be reviewed from time to time as is being done by the Regional Unit Cost Committee of NABARD. Average cost of centrifugal pumpsets for agricultural use in the state shall be adopted for formulation of the scheme. Notwithstanding these average costs financing banks are expected to finance the actual cost of the pumpset. National Bank has issued necessary circular to banks in this regard (Annexure-IV). Loan for Pumping System Depending upon the Horse Power, type and make of pumpset, type of suction and delivery pipes selected by the farmer, the cost of pumping system as quoted by the supplier is considered by the Bank. The loan for purchase of pumping system is decided after allowing for farmer's own contribution or margin money. NABARD has advised financing banks to consider actual cost of the pumpset selected by the farmer after allowing margin money and that the loan amount need not be restricted to average unit cost of pumpset for the District or the State. This would avoid under financing as well as borrowing by farmer from other sources if the bank loan is inadequate. Repayment Period Serviceable life of pumpset without much wear and tear and without much drop in efficiency is usually considered as 9 years. Therefore, the loan repayment period is considered at 9 years. Since immediate benefits start soon after installation and installation does not take longer time, no grace period is considered for loan repayment. It is presumed that the loan for electric pumpset is sanctioned by the bank after ensuring that electric power supply is readily available so that the pumpset financed by the bank would be immediately energized and commissioned. Economics Economics of financing of pumping system are worked out based on average command area, cropping pattern and average cost of pumping system. This is given in Annexure V. These are only indicative and for guidance. The economics have to be worked out in individual cases. Financial analysis shows that availment of pumpset loan for agricultural purpose is a viable proposal. Subsidy As applicable from time to time. Rate of Interest As applicable from time to time. Maintenance And Repairs of Centrifugal Pumpsets Breakdown of pumping system during irrigation specially at critical crop growth stage results in great loss to farmer. To avoid such a breakdown, it is necessary to attend to regular upkeep and maintenance of the pumping system. Following are some of the important points that should be observed for smooth operation of the equipment :- Pump and motor/diesel engine should be in perfect alignment to avoid extra load on bearings that damages impeller and couplings. Suction and delivery pipes should be self supporting. Adding weight to pipes damages casing of the pump. Gland packing should be periodically replaced. Do not tighten the gland packing more than necessary. Check oil levels. Do not run the electric motor when the voltage is below 370 volts and electric supply is receivable from a single or two phases for three phase motor. Despite regular maintenance, the pumpset might develop some trouble. Common troubles encountered and their probable causes and remedies are given in Table VII :- TABLE VII Common Troubles  in Operation of Centrifugal Pumpsets, Its Causes and Remedies Trouble Causes Remedies 1 2 3 Difficulty in starting the diesel engine pumpset Faulty fuel injection nozzle. Air in fuel pipe Check fuel injection nozzle On operating the plunger it should give a peculiar squeaking noise Engine starts but fires intermittently or stops Faulty fuel supply Fuel filter choked Tighten fuel connection Replace the parts Overheating of diesel engine Overloading of engine Lubricating oil faulty Avoid overloading Check oil level Motor starts jerking when starter is switched on Broken circuit in starter Alignment of motor is not proper Belt is not properly joined Damaged bearings Repair circuit in the starter Replace foundation bolts properly Rejoin belt properly Change bearings Motor gets heated Low voltage Starter winding may be wrongly connected Motor bearings improperly lubricated or damaged Stop motor and wait till proper voltage is restored Change connection Change bearings and lubricate them Knocking or strapping noise Ball bearings may be contaminated Worn out bearings Clean bearings and put fresh grease Replace bearings Engine consumes more oil Worn out cylinder and piston rings Check and replace wornout rings Exhaust smoke is dark/ blue Engine operating at high speed Mobil oil leaks in combustion chamber Control speed with governor Control flow of mobil oil Further Guidance The Regional Office of NABARD in the State could be contacted for any further advice and guidance for formulation of schemes for financing of agricultural pumpset etc.

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