FAQ

BENA POWER is a company with extensive experience in the production, selection, and assembly of generator sets, providing backup power solutions for a wide range of industries.

Having been active in the market for nearly two decades, we take pride in our numerous successful projects, our commitment to the highest quality of service, and our strong record of customer satisfaction.

Q How do I correctly size a diesel generator set for my facility?

A
Proper sizing depends on three key factors:

1. Load type – resistive (lighting, heaters) or inductive (motors, pumps, compressors). Inductive loads require 3–6 times their running power for starting.

2. Total running load (kW) and largest single motor starting kVA – the generator must handle the latter without a unacceptable voltage dip.

3. Altitude and ambient temperature – derate power by 3–4% per 300 m above 1000 m and by 1% per 5 °C above 40 °C.

Always perform a load study and consult a professional. Oversizing wastes fuel; undersizing causes voltage/frequency instability and premature failure.
Q What is the difference between standby, prime, and continuous power ratings?

A
- Standby (ESP - Emergency Standby Power) - For emergency use during utility failure. Max 200 hours/year, 80% average load, no overload allowed.

- Prime (PRP - Prime Power) - For variable loads with unlimited hours of operation. Average load ≤70% of prime rating, with 10% overload capability for 1 hour every 12 hours.

- Continuous (COP -Continuous Power) - For constant, non-variable loads, unlimited hours, no overload capability.

Choosing the wrong rating leads to warranty void or engine damage.
Q How often should I change the engine oil and filters on a diesel generator?

A
Standard intervals:

- Oil & filter - Every 250 - 500 running hours or 6 months, whichever comes first. Use API CK-4 or CJ-4 oil.

- Fuel filter - Every 250 hours or annually.

- Air filter - Inspect every 200 hours; replace at 1000 hours or when restriction indicator shows red.

For standby sets with low hours, change oil at least once a year because condensation and acids accumulate even without running.
Q Why does my diesel generator produce white smoke during startup? Is it a problem?

A
White smoke indicates unburned diesel fuel vapor. Common causes:

- Low cylinder compression (worn piston rings/valves)

- Low coolant temperature - glow plugs or intake heater not working

- Faulty injectors - dripping or poor atomization

- Incorrect injection timing

A small amount of white smoke in cold weather for 5-10 seconds is normal. If it persists longer or occurs in warm conditions, stop the generator and inspect the injection system and glow plugs.

Q What is the correct procedure for exercising a standby diesel generator set?

A
To maintain reliability:

1. Run under at least 40-50% of rated load-no-load running causes wet stacking (unburned fuel buildup).

2. Duration: 30-60 minutes every 2 weeks.

3. Let the engine reach stable operating temperature (coolant ≥80 °C / 176 °F) before loading.

4. Monitor oil pressure, frequency (Hz), and voltage during exercise.

5. After loaded run, cool down for 5 minutes at no load before shutdown.

Monthly load banking (≥75% load for 1 - 2 hours) is recommended if the set rarely sees high loads.
Q How do I store diesel fuel for my generator, and how long can it last?

A
Diesel degrades due to oxidation, microbial growth, and water contamination.

- Storage - Use clean, sealed, opaque tanks; keep water out (drain condensation monthly); add biocide and stabilizer.

- Shelf life - Standard diesel: 6-12 months; treated with stabilizer: 18-24 months.

- Testing - After 6 months, check for haze, sediment, or bad smell. Do not use fuel that fails clarity test.

Always rotate fuel (first-in, first-out) and filter before the fuel tank.
Q What routine maintenance should be performed after a generator runs for 1000 hours?

A
At 1000 hours (or 2 years), in addition to oil and filter changes:

- Replace fuel filters (both primary and secondary)

- Check/adjust valve lash (clearance)

- Test coolant concentration - top up with ethylene glycol anti-corrosion mix (50/50)

- Inspect and clean the radiator fins and crankcase breather

- Replace air filter element

- Test battery - clean terminals and check electrolyte level (if wet type)

- Perform a load bank test to verify full power output and exhaust gas temperature

Follow the OEM maintenance schedule-skipping 1000-hour tasks leads to overheating, loss of compression, or injector failure.
Q My generator starts but shuts down immediately - what could be wrong?

A
Common causes for start-then-stop (shutdown within 3-10 seconds):

1. Low oil pressure - check oil level; faulty oil pressure switch or sensor.

2. High coolant temperature - false reading from thermistor or air in system.

3. Overspeed - governor failure or magnetic pickup sensor misalignment.

4. Loss of magnetic pickup (MPU) signal - sensor gap too wide.

5. Fuel solenoid not staying energized - faulty fuel stop actuator or control circuit.

Check the controller’s fault code first. Never bypass safety shutdowns - they protect the engine from catastrophic damage.

FAQ

Q How do I correctly size a diesel generator set for my facility?

Q What is the difference between standby, prime, and continuous power ratings?

Q How often should I change the engine oil and filters on a diesel generator?

Q Why does my diesel generator produce white smoke during startup? Is it a problem?

Q What is the correct procedure for exercising a standby diesel generator set?

Q How do I store diesel fuel for my generator, and how long can it last?

Q What routine maintenance should be performed after a generator runs for 1000 hours?

Q My generator starts but shuts down immediately - what could be wrong?

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