FREQUENTLY ASKED QUESTIONS

• What are the main elements that should be used in genset's control panel?

1. Thermic Magnetic Switch:

There must be a Thermic Magnetic Switch in Alternator's Control Panel. Switch's thermic adjustment level must be within the alternator's nominal current.

The thermic unit of the switch protects the alternator against overloads and the magnetic unit of the switch protects the alternator against short-circuits.

Some manufacturers prefer to use economical W-otomats instead of thermic magnetic switch in control panels. It is not possible to protect the alternator with W-otomats. W-otomats' protection valves are constant and are out of alternator's nominal current.

2.Frequencymeter:

It shows the frequency of the electrical energy produced by the genset. Also it indicates the speed of the diesel engine. Since the changes in the engine speed would effect the frequency directly, it would be possible to observe the speed changes with the help of the frequencymeter. The speed changes cannot be noticed in the genset without frequencymeter.

• What are the drawbacks of running alternator below nominal speed?

2.1. When the speed is lower than the optimum, nominal voltage can be obtained by the voltage regulator's transmission of more current. When the voltage regulator transmits high current, exciter windings can be damaged.

Sometimes the extra current transmitted by the voltage regulator won’t be enough to keep the voltage constant and drops in the voltage occurs. In such cases the moment of the electrical motor, which is directly proportional with the square of the voltage, has big losses when the voltage drops.

2.2.The frequency will decrease when  the engine's speed decreases. As a result, the speed of the machinery supplied by the alternator will decrease in respect to the frequency.

2.3. When the speed of engine and the frequency drop, alternator works in high magnetic field to hold the voltage at nominal value. In high magnetic field loses increase and abnormal heat occurs.

2.4. When the speed of engine decreases, obtained power decreases. Because power is a function of speed.

3. Time Counter: Time counter is needed to see the total work time for periodical controls.

• What are the specifications of diesel engines used in gensets?

1. The flywheel of the diesel engine should be heavy to stabilise the voltage of the alternator. With the advantage of the flywheel's inertia movement, combustion of the diesel engine's effect on the alternator shaft will be minimised.

When the genset is started for the first time if the light blinks it is understood that the weight of the flywheel is insufficient, a heavier flywheel should be mounted.

2. There must be a regulator on the fuel pump of diesel engine. This regulator keeps the speed constant in sudden load changes.

3. Type of the diesel engine's fan should suck the air above the engine and force it out.