Question

Overloading permitted in DG set is about
1. 125%, 2 hrs
2. 110%, 2 hrs
3. 125%, 1 hr
4. 110%, 1 hr

Answer 1

Correct Answer - Option 4 : 110%, 1 hr

Load pattern and DG set capacity:

• The average load can be easily assessed by logging the current drawn at the main switchboard on an average day.
• The 'over load' has a different meaning when referred to the D.G. set. Overloads, which appear insignificant and harmless on electricity board supply, may become detrimental to a D.G.set.
• Diesel engines are designed for 10% overload for 1 hour in every 12 hours of operation.
• The A.C. generators are designed to meet 50% overload for 15 seconds as specified by standards.
• The D.G.set/s selection should be such that the overloads are within the above specified limits. It would be ideal to connect steady loads on DG set to ensure good performance.
• Alongside alternator loading, the engine loading in terms of kW or BHP, needs to be maintained above 50%. Ideally, the engine and alternator loading conditions are both to be achieved towards high efficiency.