1. Tell us what is the effect of positive feedback on stability of the system?

Positive feedback is not used generally in the control system because it increases the error signal and drives the system to instability. But positive feedbacks are used in minor loop control systems to amplify certain internal signals and parameters

2. Tell us what is SF6 Circuit Breaker?

SF6 is Sulpher hexa Flouride gas.. if this gas is used as arc quenching medium in a Circuitbreaker means SF6 CB.

3. Suppose two bulbs of 100w and 40w respectively connected in series across a 230v supply which bulb will glow bright and why?

Since two bulbs are in series they will get equal amount of electrical current but as the supply voltage is constant across the bulb(P=V^2/R).So the resistance of 40W bulb is greater and voltage across 40W is more (V=IR) so 40W bulb will glow brighter.

4. What is 2 phase motor?

A two phase motor is a motor with the the starting winding and the running winding have a phase split. e.g; ac servo motor. where the auxiliary winding and the control winding have a phase split of 90 degree.

5. Explain me what will happen when power factor is leading in distribution of power?

If their is high power factor, i.e if the power factor is close to one:
☛ a) Losses in form of heat will be reduced,
☛ b) Cable becomes less bulky and easy to carry, and very cheap to afford, &
☛ c) It also reduces over heating of tranformers.

6. Tell us are you confident in your ability to interpret any electrical diagram and repair most equipment in safe manner?

I am very confident in my ability to interpret electrical diagrams. This is one of my stronger suits in my current role and I have a lot of experience doing so. When it comes to repairing equipment, I always think of safety first. I have taken additional safety courses as well.

7. Explain me what Are the Most Important Safety Concerns for Electricians?

Interviewers who ask this question want to see that you are safety-minded. They want to see that you have a good understanding of the risks associated with this type of work and get a sense of how concerned you are about safety in the way you approach your work.

8. Why Should We Hire You as Electric Mechanic?

You'll find this question near the end of the interview. If you feel you have something special to offer that didn't get mentioned or prompted in the interview, then say it here. Avoid using cliched buzzwords like "hard-working," "fast learner" or "gets along well with others." Phrase your response in terms of what you can do for the employer, not how the job can benefit you. Use this question as your opportunity really to sell yourself to the hiring manager.

9. Tell us what has been your greatest achievement?

Reciting academic or obvious work achievements are not the best answers – they won't distinguish you from the crowd. Instead, say something that will set you apart, that speaks about your aspirations and values. Organising a sport or fund-raising event, taking part in a race, or learning and using a new language or musical instrument are good examples. ‘I was nominated to be a representative to be go-between for our team and the senior management stakeholders', is another.

10. Do you know what is a System?

When a number of elements or components are connected in a sequence to perform a specific function, the group of elements that all constitute a System

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11. Tell me what is meant by knee point voltage?

Knee point voltage is calculated for electrical Current transformers and is very important factor to choose a CT. It is the voltage at which a CT gets saturated.(CT-current transformer).

12. Tell me what is IDMT relay?

It is an inverse definite minimum time relay.In IDMT relay its operating is inversely proportional and also a characteristic of minimum time after which this relay operates.It is inverse in the sense ,the tripping time will decrease as the magnitude of fault current increase.

13. Tell me how many types of colling system it transformers?

1. ONAN (oil natural,air natural)
2. ONAF (oil natural,air forced)
3. OFAF (oil forced,air forced)
4. ODWF (oil direct,water forced)
5. OFAN (oil forced,air forced)

14. Tell me whats the one main difference between UPS & inverter? And electrical engineering & electronics engineering?

Uninterrupt power supply is mainly use for short time. means according to ups VA it gives backup. ups is also two types: on line and offline. online ups having high volt and amp for long time backup with with high dc voltage. but ups start with 12v dc with 7 amp. but inverter is startwith 12v, 24,dc to 36v dc and 120amp to 180amp battery with long time backup.

15. Explain Do You Specialize in Any Particular Areas?

Along with qualifications, an employer will want to know if you have any particular specializations. For example, some electricians specialize in electrical systems and controls, wiring, or electro-mechanical repairs. Others may have particular expertise in reading blueprints or general troubleshooting.

16. Tell us what Procedures Do You Follow Before Finalizing a Job?

Details are critical to the work of electricians, so be prepared to describe to an interviewer what you do to make sure that everything is correct with a project before you are ready to sign off on it as complete. For example, explain how you verify that things are working and what steps you take to make sure that every detail is as it should be.

17. Tell me of a few tools of the trade that you are comfortable with?

Bench lathes, drills, coils, terminal boards and chassis are just some of the tools that I work well with.

18. Tell us have you ever worked in a leadership role?

Recently, I was commissioned to train, mentor and guide a group of 5 apprentices, which is where I was able to prove my leadership abilities.

19. Explain About Your Work Experience?

Employers are looking for steady work employment and not short term assignments with big gaps between jobs. You should be prepared to explain any such gaps between work. Another piece of advice is to focus on work experience relevant to the position you are currently applying for as well as your most recent work history.

20. Tell us why computer humming sound occurred in HT transmission line?

This computer humming sound is coming due to ionization (breakdown of air into charged particles) of air around transmission conductor. This effect is called as Corona effect, and it is considered as power loss.

21. Can you explain me the difference between a four point starter and three point starter?

The shunt connection in four point stater is provided separately form the line where as in three point stater it is connected with line which is the drawback in three point stater

22. Tell us what is stepper motor.what is its uses?

Stepper motor is the electrical machine which act upon input pulse applied to it. it is one type of synchronous motor which runs in steps in either direction instead of running in complete cycle.so, in automation parts it is used.

23. Explain me what is Holding current?

When scr is conducting current in forward conduction state, scr will return to forward blocking state when the anode current or forward current falls below a low level called Holding current
Note: Latching current and Holding current are not same. Latching current is associated with the turn on process of the scr whereas holding current is associated with the turn off process. In general holding current will be slightly lesser than the latching current.

24. Can you explain me what is Control System?

In a System the output and inputs are interrelated in such a manner that the output quantity or variable is controlled by input quantity, then such a system is called Control System.
The output quantity is called controlled variable or response and the input quantity is called command signal or excitation.

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25. Tell us why thyristor is considered as Charge controlled device?

During the triggering process of the thyristor from forward blocking state to forward conduction state through the gate signal, by applying the gate signal (voltage between gate and cathode) increases the minority carrier density in the p-layer and thereby facilitate the reverse break over of the junction J2 and thyristor starts conducting. Higher the magnitude of the gate current pulse, lesser is the time required to inject the charge and turning on the scr. By controlling the amount of charge we can control the turning on time of the scr.