DG A & B Checks Explained | Diesel Generator Maintenance | Working Principle, & Preventive checks

Описание: What This Video Is About
Today, you will learn the importance of DG checks A and B, how they are performed, and why they prevent most generator failures. This video focuses only on DG A Check and DG B Check. In the next video, we will explain DG C and DG D checks, which include major servicing and complete overhaul activities.

🔹 Why DG Maintenance Is Critical

A diesel generator is a standby power system, but during an emergency, it becomes the primary power source. If the DG fails to start or trips during operation, the consequences can include:

• Power outage during critical operations
• Data loss in IT facilities
• Patient safety risks in hospitals
• Equipment damage
• Financial and reputational losses

Most DG failures do not happen suddenly. They develop slowly due to neglected inspections, poor housekeeping, fuel contamination, battery weakness, and loose electrical connections. DG A and B checks are designed to detect these issues early.

🔹 DG Maintenance Classification Explained

DG maintenance is typically divided into four levels:

• DG A Check – Daily and weekly operational readiness checks
• DG B Check – Preventive maintenance checks
• DG C Check – Annual or major servicing
• DG D Check – Complete overhaul

This video covers DG A and B checks, which together eliminate nearly 70–80% of common DG failures.

🔵 DG A CHECK – DAILY & WEEKLY INSPECTIONS

DG A Check ensures that the generator is always ready to start. These checks are usually performed by the operator or shift engineer.

✅ Visual Inspection

The inspection begins with a complete visual check of the DG:

• Engine oil leakage around filters, gaskets, and joints
• Diesel leakage from fuel lines, injectors, and pipe connections
• Coolant leakage from radiator hoses, clamps, and water pump
• Condition of belts, hoses, and clamps
• Cleanliness of the DG room and ventilation paths

Even a small leak can lead to major failure if ignored.

✅ DG Room Ventilation & Housekeeping

Proper ventilation is essential to maintain engine temperature. Fresh air intake and hot air exhaust paths must be clear at all times. The DG room should be:

• Clean and dry
• Free from combustible materials
• Well illuminated
• Properly ventilated

Good housekeeping improves safety and inspection accuracy.

✅ Battery & Electrical Readiness

Battery failure is one of the top causes of DG non-starting. A Check includes:

• Battery terminal tightness
• Corrosion inspection
• Cable condition
• Charger status

✅ Control Panel & Meter Readings

The control panel provides the health status of the DG. Parameters checked include:

• Voltage on all phases
• Frequency stability
• Load percentage
• Running hours
• Alarm indications
🔑 Outcome of DG A Check

DG A Check ensures the generator is visually healthy, electrically ready, and operationally responsive.

🟠 DG B CHECK – PREVENTIVE MAINTENANCE

DG B Check goes deeper and is usually performed by AMC or OEM technicians.

✅ Air Intake System Inspection

• Air filter restriction indicator check
• Air filter cleaning or replacement
• Intake duct inspection

Restricted airflow increases fuel consumption and smoke.

✅ Fuel System Preventive Checks

• Fuel-water separator draining
• Fuel hose and clamp inspection
• Fuel transfer pump operation check
• Day tank filling logic verification

Water in diesel is a silent killer of injectors.

✅ Exhaust System Inspection

• Exhaust manifold joints
• Flexible connectors
• Silencer condition
• Soot leakage

Exhaust leaks increase back pressure and reduce engine efficiency.

✅ Cooling System Maintenance

• Radiator fin cleaning
• Coolant hose inspection
• Airflow restoration

Overheating is a major cause of DG tripping.

✅ Alternator & Electrical Health

• Alternator heating inspection
• Dust accumulation check
• Electrical termination tightness
• Cable condition

Loose connections cause overheating and failures.

✅ Mechanical & Control Checks

• Engine-alternator coupling alignment
• Linkage lubrication
• AVR voltage stability check
• Protection relay testing
• Battery CCA testing

✅ Automation System Testing

• AMF / ATS auto-start test
• Load transfer to DG
• Return to mains operation
• Cooldown and controlled shutdown

🔑 Outcome of DG B Check

DG B Check ensures long-term reliability, efficiency, and safety.

🔐 Safety Importance During DG Checks

Safety is non-negotiable during DG maintenance:
• Proper ventilation
• No smoking near fuel systems
• Correct earthing
• Fire extinguishers available
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