DG ( Diesel Generator)

D.G is a combination of diesel engine and alternator. Engine generates the mechanical energy and this mechanical energy is converted in to electrical energy with the help of alternator.

PARTS OF DG:-
Alternator
Engine
Radiator
Batteries
Self Starter
Priming Pump
Dynamo
Turbo charger
Fuel filter
bypass filter
Silencer
Air filter
Breather
Radiator fan
Terminal box
Pressure temperature pump
Thermostat
EFC
Actuator
Magnetic pike up unit
Automatic voltage regulator
Water pump
Water separator
Coolant level indicator
vacuum indicator

Alternator:- it is a rotating device which converts the mechanical energy in to electrical energy.

Engine:- it is a device which generaters the mechanical energy.

Radiator:- it consists of water with mixture of coolant which circulates the water to engine which absorb the heat generated from the engine. the PH value of coolant is below 9 ppm.

Batteries:- it is used to start the engine, it gives dc supply to self stater. its voltage range is between 24v to 27v. when D.G is stop mode the batteries are charged by E.B (Electricity Board) supply. When D.G is on running condition the batteries are charged by dynamo. generally lead acid call batteries the more preferable because it has high electrical resistance and mechanical strength.

Self Starter:- it is used to supply the starting torque to the engine. the minimum speed of the stater is 200 rpm below which the engine fails to start.

Priming pump:- it is an oil circulating pump which is used to circulate the oil from oil tank to all parts of engine which is located at the bottom of the engine.

Dynamo:- it is rotating device  which converts mechanical energy into electrical energy (DC supply). this DC supply is used to charge the batteries.

Turbo Charger:- it is a multi function  rotating device, which sucks the air from outside through the air filter and supplies this forced air to engine for combustion process. its another function is to collect smoke which is generated in the engine and send it out through chimneys. its rotating speed is greater then 1,00,000 rpm.

Fuel Filter:- its function is to the fuel.

Lube oil Filter:- its function is to filter the engine oil which is circulating from oil tank to all engine parts.

Bypass Filter:- its function is to filter the engine oil which is circulating from all engine parts to oil tank.

Silencer:- its function is to reduce the sound which is generated from the smoke and to send it out trough chimmeney.

Air Filter:- its function is to are which collected from outside.

Breather:- its function is to absorb the moisture the engine.

Radiator Fan:- its function is to absorb the heat which is generated by the engine and send it outside through the radiator.

Terminal Box:- it is located at the top of the alternator. its consist R,Y, B terminals coming from alternator.

P.T (Pressure Temperature pump):- its function is to build up pressure of the fuel.

Thermostat:- it is a coil which is connected to heat exchange tank to sense the temperature of water. if water temperature reaches 90^oC then DG gets tripped.

EFC (Electrica Fuel Controller):- its function is to control the input fuel depending on the speed variation.

Actuator:- it consists a valve which gives the of fuel depending on speed. it works with help of PWM (Pulse Width Modulation) technique. this PWM signal is coming from ECP(Electronic Control Panel).

Magnetic pickup unit:- its function is to sense the speed of the engine. 

AVR(Automatic Voltage Regulator):- it is located in the alternator which the constant output voltage. if AVR fails more fluctuations will occur in output voltage.

Water Pump:- it is water circulating pump, which circulates the water from radiator to engine.

Water Separator:- it is used to filter the water from the input fuel.

Coolant Level Indicator:- it is used to find out the coolant level in the radiator. it is also called coolant glass indicator.

Vacuum Indicator:- it is used to find out amount dust particles in the filter.

Types of checks Done On DG Sets:- 

1. A Check
2. B Check
3. C Check
4. D Check

A Check:- it is done every day 

• Check the diesel level in the tank 
• Check the engine oil level
• Check the radiator water level
• Check the fan belt tension
• Check the speed of the engine
• Check the water in the water separator
• Check the water temperature
• Check the output voltage of the alternator
• Check the the specific gravity, distilled water level and voltage of batteries
• Check any leakages of batteries

B Check:- It is done fro every 300 running hours or 6 months

• Repeat the A check
• Change the engine oil
• Change the lube oil filters
• Change the bypass filters
• Check the fuel pressure
• Clean the Air filters
• Clean the radiator
• tighten the fan belt tension
• Check coolant level in the water
• Clean or change the breather

C Check- it is done for every 1500 running hours or 1 year

• Repeat A & B Check
• Change the air filters
• Clean the fuel tank inside
• Service the engine and alternator

D Check:- this is done for every 6000 running hours or 2 years

• Repeat A, B & C check
• fuel pump calibration 
• adjust the inspectors and valves
• Check the turbo charger

Safety Measures of Engine:-

1. Water level in radiator
2. Radiator Fan belt
3. battery charging voltage and amps
4. Drain water from water separator
5. check air filter
6. Oil pressure
7. Fuel pressure
8. Water Temperature

Safety Measures Of Alternator:-

1. Check output voltage
2. Check output Frequency
3. Check output Current

Types Of Sensor:-

1. WT (Water Temperature) Sensor
2. LCWL (Low Coolant Water Level) Sensor
3. OS (Over Speed) Sensor
4. LLOP (Low Lube Oil Pressure) Sensor

Safety Ralays Provided For DG Set:-

1. water temperature relay
2. over current relay
3. earth fault relay
4. reverse power relay
5. under voltage relay
6. over voltage relay

Types of Earthing Provided For DG:- there are four earth pits required for DG set.

1. Two for neutral earthing
2. Two for body earthing

Types of Protective Devices For DG Set:-

• Breather
• Water temperature relay
• Over speed relay
• Low coolant water level relay
• Low lube oil pressure relay
• Thermostat
• Electronic fuel controller
• Magnetic  pick up unit

Types of Synchronizing:-

1. Dark Lamp Method
2. Bright Lamp Method

Condition For Synchronizing the DG:-

1. Voltage must be equal
2. Frequency must be equal
3. Phase sequence must be equal

If these condition are not gets then the DG may not get the synchronize.

Meters Provided For DG Set:-

1. Power meter are used for measuring for KW, KVAR, MWH and PF.
2. AC meter are used for measuring for Line voltage, phase voltage, phase current and Frequency.
3. Engine meter are used for measuring for battery voltage, Oil temperature, Water temperature, oil Pressure, Fuel pressure, RPM and Running Hours.