Bissoy.com
Doctors Medicines MCQs Q&A

Why are relays used for driving the motors?

Why are relays used for driving the motors? Correct Answer they can be used as switch as well as they provide isolation

Relay is the electrically controlled switch and it allows isolation of two separate sections of the system. It has three main components: the coil, the common pole and the contacts. When an electric field is applied to the coil; it gets energized and generates a magnetic field which will force the common pole to change contact from Normally Closed to Normally Open.

Related Questions

Following statements are given for DC motors (a) DC motors require less maintenance than AC motors (b) DC motors cannot provide high starting torque (c) DC motors are not suitable for very high-speed applications (d) The methods of speed control of DC motors are simpler and less expensive than those of AC motors Which of the following statements are correct?
Consider the following statements regarding ac drives: 1. For the same kW rating, ac motors are 20% to 40% light weight as compared to dc motors. 2. The ac motors are more expensive as compared to same kW rating dc motors. 3. The ac motors have low maintenance as compared to dc motors. Which of the above statements are correct?
Which of the following statements are correct for synchronous motors? 1. Synchronous motors are well-suited for direct connection top reciprocating compressors. 2. Over-excited synchronous motors are most commonly used for power factor improvement. 3. Synchronous motors are generally used for current regulation of long transmission lines Select the correct answer using the code given below.
Why are solid-state relays advantageous over electromechanical relays?
Mr. Justin wanted to test his students' understanding of the 'nature of weekly markets from a seller's point of view'. Which of the following questions are suited to test this? i. Can a weekly market address all the needs of a family? Why or why not? ii. Compare and contrast the characteristics of a weekly market and a permanent shop. iii. Are you likely to find a well-known brand as part of a weekly market? Why or why not? iv. Can any seller increase their price a lot compared to other sellers in a weekly market? Why or why not?
Two statements are given, followed by two conclusions numbered I and II. Assuming the statements to be true, even if they seem to be at variance with commonly know facts, decide which of the conclusions logically follow(s) from the statements. Statements: All wires are motors. All motors are pumps. Conclusions: i. All wires are pumps. ii. Some motors are wires.
Magnetic disk, electric motors, speakers, relays use which of the following elements?
Each question given below consists of a statement, followed by two arguments numbered I and II. You have to decide which of the arguments is a 'strong’ argument. Statement: Should speed driving be imposed heavy penalties? Arguments: I. Yes, speed driving is one of the major causes of road deaths as per statistics. II. No, speed driving helps a person to reach his destination soon.
A entrusted his car to B for plying it as a taxi. B employed C as a cleaner. B gave the taxi to C for taking a driving test and to obtain a driving licence. C while giving the driving test seriously injured D. D filed a case against A, the owner of the vehicle.
The question given below consists of a statement, followed by three arguments numbered I, II and III. You have to decide which of the arguments is/are ‘strong’ arguments and which is/are ‘weak’ arguments and accordingly choose your answer from the alternatives given below each question. Statement: A moment of silence, please, for the world’s cheapest car, which had all but has died in India. It was almost 10 years old. The Nano’s death was confirmed by production numbers: Tata Motors Ltd. produced 1 unit in June, down from 275 in the same month last year. Exports were zero, versus 25 in June 2017. The company acknowledged that the car in its ‘present form cannot continue beyond 2019’. Why? Arguments: I. The expiry of the ‘people’s car’, as Tata Motors branded it in 2008, holds lessons for automakers hoping to make it in India: While consumers may be value-conscious, cutting costs to the bone in pursuit of a gimmicky claim to fame is of no use if the end result is a second-rate vehicle with a tendency to catch fire.  II. The Nano’s failure to sell stands is in stark contrast to the rest of the Indian car market. From motorbikes to cars and trucks, growth in every segment is picking up.  III. This is a market where electric vehicles are non-existent and the chatter over fancy ideas such as future mobility and autonomous vehicles, which pervades the rest of the auto world, is muted.