20EE211-Electric Drives and Control-Surprise Quiz 2

The conduction period of diode in Half-wave uncontrolled rectifier for resistive load is ______________

• π

• 2π

• 3π

• 4π

A single phase fully controlled converter bridge is used for electric braking of separately excited DC motor. Assume that the load inductance is sufficient to ensure continuously and ripple free load current. Then, the firing angle for a load current of 10A will be _________

• 44°

• 51°

• 129°

• 136°

The armature voltage of a dc motor provides ________

• constant torque drive

• constant voltage drive

• constant current drive

• constant power drive

In a three-phase controlled bridge rectifier, with an increase of an overlap angle the output voltage will be _______

• decrease

• increase

• does not change

• depends upon the load inductance

Which type chopper circuit is generally used for the reversible DC motor and corresponding braking operation?

• Type A chopper

• Type E chopper

• Type D chopper

• Type C chopper

For controlling the speed of the dc motor of 200 HP rating, the following types of converters are normally used ______

• single phase fully controlled converters

• single phase dual converters

• three phase fully controlled converters

• three phase dual converters

The closed loop control of DC drives helps in achieving the _________

• maintenance of constant speed and constant firing angle

• maintenance of constant speed by changing firing angle

• maintenance of constant firing angle only

• maintenance of constant load on the motor

In case of armature controlled separately excited dc motor drives with closed loop control, an inner current loop is useful because, it ________

• limits the speed of the motor to a safe value.

• helps in improving the drive energy efficiency

• limits the peak current of the motor to the permissible value

• limits the average currents of the drives

In a three phase DC drive, what is the minimum number of thyristors required for full-wave rectification?

• 2

• 3

• 4

• 6

A DC motor is operated from type-A chopper is switched to type-B chopper. How does the motor operate, when type A and type B are in operation respectively?

• Plugging and motoring

• Motoring and plugging

• Regenerative braking and motoring

• Motoring and regenerative braking