DOL Starter

Question 1

What is a direct online starter?

Answer 1

A direct online starter is an electrical device used to start an electric motor directly from the power supply.

Question 2

True or False: A direct online starter is suitable for large motors.

Answer 2

False

Question 3

What is the primary function of a direct online starter?

Answer 3

To connect the motor directly to the power supply for starting.

Question 4

Fill in the blank: A direct online starter is commonly used for motors with a rating of up to ____ kW.

Answer 4

15

Question 5

What components are typically included in a direct online starter?

Answer 5

A contactor, overload relay, and a start/stop push button.

Question 6

Multiple choice: Which of the following is a disadvantage of using a direct online starter? A) Simplicity B) High starting current C) Low cost

Answer 6

B) High starting current

Question 7

What happens during the starting phase of a motor with a direct online starter?

Answer 7

The motor receives full voltage and current, leading to high starting torque.

Question 8

True or False: Direct online starters can be used for variable speed applications.

Answer 8

False

Question 9

What is the role of the overload relay in a direct online starter?

Answer 9

To protect the motor from overheating and damage due to excessive current.

Question 10

Fill in the blank: The direct online starter is best suited for ____ applications.

Answer 10

Fixed-speed

Question 11

Multiple choice: Which type of motor is commonly used with direct online starters? A) Induction motor B) Synchronous motor C) Stepper motor

Answer 11

A) Induction motor

Question 12

What is the typical starting current ratio for a motor using a direct online starter?

Answer 12

6 to 8 times the full load current.

Question 13

True or False: A direct online starter requires additional control circuits for operation.

Answer 13

False

Question 14

What is the typical control method for a direct online starter?

Answer 14

Using start and stop push buttons.

Question 15

Fill in the blank: The contactor in a direct online starter is responsible for ____ the motor.

Answer 15

energizing

Question 16

Multiple choice: Which of the following is NOT a feature of a direct online starter? A) Simple design B) High efficiency C) Soft starting capability

Answer 16

C) Soft starting capability

Question 17

What does the term ‘inrush current’ refer to in the context of direct online starters?

Answer 17

The initial surge of current when the motor starts.

Question 18

True or False: Direct online starters can be used in applications requiring frequent starts and stops.

Answer 18

False

Question 19

What is a common application for direct online starters?

Answer 19

Pumps, fans, and compressors.

Question 20

Fill in the blank: Direct online starters are typically mounted in ____ boxes.

Answer 20

control

Question 21

Multiple choice: Which of the following is a key benefit of using a direct online starter? A) Cost-effectiveness B) Requires complex programming C) High energy consumption

Answer 21

A) Cost-effectiveness

Question 22

What is the typical response time of a direct online starter when the start button is pressed?

Answer 22

Instantaneous

Question 23

True or False: Direct online starters can be used for multi-phase motors.

Answer 23

True

Question 24

What is the preferred voltage for direct online starters in industrial applications?

Answer 24

Typically 230V, 400V, or 480V.

Question 25

Fill in the blank: The direct online starter is best for applications that can tolerate ____ starting currents.

Answer 25

high