FM Techie

Standard Operating Procedure (SOP) for Diesel Generator Daily Check Purpose: To ensure that the diesel generator is in good condition and ready for use. Scope: This SOP applies to all personnel responsible for operating the diesel generator. Procedure: Check the fuel level: Check the fuel level of the diesel generator and ensure it is above the minimum level required for operation. Check the oil level: Check the oil level using the dipstick and ensure it is within the safe range. Check the coolant level: Check the coolant level in the radiator or expansion tank and ensure it is within the safe range. Inspect the air filter: Check the air filter for any signs of damage or blockages. Replace or clean the filter as necessary. Check the battery: Check the battery terminals for corrosion and clean them if necessary. Check the battery voltage using a voltmeter and ensure it is within the acceptable range. Inspect the belts: Check the condition and tension of the belts. Replace or adjust them...

When AC voltage is directly applied to the stator windings of a 3 phase induction motor, the motor draws a high starting current which may disturb the system voltage. The starting current can be 6 to 7 times the full load current of the motor. To reduce this starting current, different types of motor starters are used in industrial applications. TYPES OF STARTERS: DIRECT ONLINE STARTER (DOL): AC voltage is directly applied to the stator windings. No effort is made to reduce the starting current. DOL starters are generally used for motors up to 10 HP. Control Circuit: The control circuit of a DOL starter includes a contactor, overload relay, and push button switches. STAR DELTA STARTER: Initially, the stator windings are connected in star configuration. Once the motor reaches 2/3rd of its normal speed, the stator windings are switched to delta connection. This reduces the starting current to 1/3rd compared to a DOL starter. Types of Star Delta Starters: Manual Semi automatic Fully autom...

  Buchholtz Relay – A Quick Overview What is a Buchholtz Relay? The Buchholtz relay, also known as a gas relay or sudden pressure relay, is a protective device used in oil filled transformers. It is mounted in the pipeline between the conservator oil tank and the main transformer tank. This relay helps in detecting incipient faults and prevents severe damage by triggering alarms and circuit breaker mechanisms. Working Principle of Buchholtz Relay The relay functions using two distinct detection modes: 1. Slow Gas Accumulation Detection Over time, gas is generated due to insulating oil decomposition caused by slight overloading or minor faults. This gas accumulates at the top of the relay, pushing the oil level down. A float switch is triggered, activating an alarm signal, which may also indicate slow oil leaks. 2. Rapid Gas Accumulation Detection (Arc Faults) If an internal fault occurs, gas production increases rapidly, and oil flows quickly into the conservator. A vane switch, lo...

Current Transformers a. A current transformer is a step down instrument for measuring the high value current in L.T /H.T/ E.H.T lines b. It has one or two windings or a bus bar or a heavy line conductor surmounted by a core having large number of thin wires. c. In a C.T the number of turns is inversely proportional to the current and it is connected in series in the line d. C.T is used for metering, recording and relay circuits for different requirements. e .C.T must have its secondary always closed through relays/short circuited and no fuse should be used. However the fuses can be used in shunt circuits while in service. f. Never open a secondary circuit of a C.T which may have high potential due to high impedance and endanger to personnel operating. g. Polarity is important in connecting a C.T in the circuit h. In calibrating a C.T’s impedance burden the configuration of different coil connection in series or in parallel is to be kept in mind. For safety purposes one of the secondary...

FILTER FEED PUMPS Filter Feed Pumps are used to draw water from the clarified water sump and pass it through the Pressure Sand Filter (PSF) and Activated Carbon Filter (ACF), which are installed in series to improve water quality. PRESSURE SAND FILTER (PSF) Working Principle: The upper layers of sand perform the actual filtration function, while gravel layers provide physical support. Specialized sand with a specific particle size is used to trap solid impurities present in water. The particles get entrapped in the spaces between sand grains, eventually blocking water flow. When the pressure drops beyond a set limit, the sand is cleaned by backwashing with water. Backwashing reverses the flow, fluidizing the sand bed and removing lighter solid particles as waste. Operation And Maintenance Considerations Filtration is followed by a short backwash sequence. The filter requires backwashing when the pressure drop across the filter reaches 0.5 kg/cm². Best practice: Backwash once per shift,...

CLARIFIER/ SETTLING TANK 1 The sewage inlet pipe brings sewage from the aeration tank. 2 The center-feed well takes this incoming sewage and gently releases it in the settling tank, without causing any disturbance or turbulence. 3 The sludge is only slightly heavier than water; so it takes time to sink. It slides down the steeply sloped walls of the tank toward the center of the bottom. 4 The bacterial flocs7 collect here in high concentration. 5 The sludge delivery pipe delivers the slurry to the pumps (6). 6 There are two identical pumps. Since the flow rate of these pumps is fixed, they need to be turned off periodically to bring down the net flow rate to achieve the desired MLSS ratio. This is a critical operation, because if flocs remain in the settling tank for more than 30 minutes, the microorganisms die due to lack of oxygen. 7 The T-shaped header assemble joins the outlet pipes of both pumps, and delivers the sludge to the aeration tank. 8 The clear water rises to the top of t...

 AERATION TANK The Aeration tank is at the heart of the treatment system. The bulk of the treatment is provided here, employing microbes/bacteria for the process.  The main function of the Aeration tank is to maintain a high population level of microbes. This mixture is called MLSS (Mixed Liquor Suspended Solids). The mixed liquor is passed on to the clarifier tank, where the microbes are made to settle at the bottom.  The settled microbes are recycled back to the aeration tank. Thus they are retained for a long period within the system. 1 The inlet pipe brings sewage from the raw sewage lift pump  2 The baffle wall does not let the incoming sewage and sludge go across the tank toward the outlet pipe (6). The wall forces the mix toward the bottom of the tank;  3 The tank is always filled till this level 4 The Outlet Launder collects the sewage and delivers it to the outlet pipe (6). 5 The net prevents entry of debris in the outlet pipe (6).  6 The outlet pi...