What controls the speed of an alternator and why should the speed maintained?

The automatic drive controls the alternator’s rotational speed which allows the alternator to maintain a constant 400-Hz AC output. Figure 9-78. The engine of the automobile can change rpm while the speed of the car remains constant. This is the same process that occurs for an aircraft AC alternator.

Why is a constant speed drive used to control the speed of some aircraft?

Why is a constant speed drive used to control the speed of some aircraft engine driven generators? A) So that the frequency of the alternating current output will remain constant. So that the voltage output of the generator will remain within limits.

What happens if speed of alternator increases?

AS THE SPEED OF AN ALTERNATOR INCREASES, THE FREQUENCY.

How do changes in speed affect the output voltage of an alternator?

Current is inverse with voltage. When the alternator current is high at low speed, battery voltage will drop, and will need more time to get fully charged. But when alternator output current is low at low speed, the battery voltage is high as the battery get enough power for recharging.

Are alternators constant speed?

Since the various electrical devices operating on ac supplied by alternators are designed to operate at a certain voltage and at a specified frequency, the speed of the alternators must be constant; however, the speed of an airplane engine varies. This stepping up of speed is known as overdrive.

How many hours will a 140 ampere hour battery deliver 15 amperes?

112.5 ampere-hour. How many hours will a 140 ampere-hour battery deliver 15 amperes? 9.33 hours.

What is constant speed motor?

This motor combines a power on activated type clutch and brake with an induction motor. It is ideal for high-frequency starting and stopping. Suitable for applications where the motor is operated starting, stopping and reversing repeatedly and the motor is operated at synchronous speed regardless of load torque.

Which type of rotor is best for turbo alternator?

Smooth cylindrical type rotor is generally used for high speed alternators or turbo alternators.

What is the least used type of alternator?

Revolving-Armature-Type Alternators: The revolving-armature-type alternator is the least used of the two basic types. This alternator uses an armature similar to that of a DC machine with the exception that the loops of wire are connected to sliprings instead of to a commutator.

How is a constant speed drive used in an alternator?

A unit called a constant-speed drive (CSD) is used to ensure the alternator rotates at the correct speed to ensure a 400- Hz frequency. The CSD can be an independent unit or mounted within the alternator housing. When the CSD and the alternator are contained within one unit, the assembly is known as an integrated drive generator (IDG).

What should the frequency of an alternator be?

Aircraft AC alternators should produce a frequency of approximately 400 Hz. If the frequency strays more than 10 percent from this value, the electrical systems do not operate correctly.

What is the speed of an alternator in India?

Such a rotating speed is called Synchronous speed of the alternator In India the frequency of an alternating emf is standard and which is equal to 50 Hz. To get the constant frequency for different poles, the alternator rotates at a different speed (synchronous speed).

How is the output of an alternator dependent?

In essence, while maximum alternator output is dependent on the rotational speed of the input shaft, the actual output is load-dependent. That basically means that an alternator will never generate more current than is called for by the momentary demands of the electrical system.

What is the voltage regulation of an alternator?

Voltage Regulation of an Alternator the voltage regulation of an alternator is defined as the change in its terminal voltage when full load is removed, keeping field excitation and speed constant, divided by the rated terminal voltage. The value of the regulation not only depends on the load current but also on the power factor of the load.

Why is there no voltage build up in a self excited alternator?

1. Separately excited system of Alternator 2. Self excited system of Alternator Sometimes you may face one problem that there is no voltage build-up in the Self-excited Alternator. The reason is lack of Residual Magnetism.