1. Explain the methods for starting an induction motor?
The different methods of starting an induction motor:
a) DOL:direct online starter
b) Star delta starter
c) Auto transformer starter
d) Resistance starter
e) Series reactor starter
2. Tell us how important is safety to you?
Safety in this profession is very important for every worker working inside the plant. A small mistake can lead to a big hazard and hence every minor chance of a mistake should be taken seriously.
3. Tell me what are the secondary engine parameters?
N2, N3, fuel flow, oil pressure, oil temperature, oil quantity and engine vibration. FCOM 1 70.20.1
4. Tell me what is your greatest weakness and what steps are you taking to improve?
Literature...But where this factor needs to be mastered, then there is no way back down.
5. Do you know principle of operation of a generator?
An electric generator is a machine that converts mechanical energy into electrical energy. An electric generator is based on the principle that whenever flux is cut by a conductor, an e.m.f. is induced which will cause a current to flow if the conductor circuit is closed. The direction of induced e.m.f. (and hence current) is given by Fleming's right hand rule.
6. Tell me what are the different types of losses in DC Machines?
The losses in a d.c. machine (generator or motor) may be divided into three types
1. Copper losses: These losses occur due to currents in the various windings of the machine.
2. Iron or core losses: These losses occur in the armature of a d.c. machine and are due to the rotation of armature in the magnetic field of the poles. They are of two types
a. Hysteresis loss: Hysteresis loss occurs in the armature of the d.c. machine since any given part of the armature is subjected to magnetic field reversals as it passes under successive poles.
b. Eddy current loss: The voltages induced in the armature conductors produce circulating currents in the armature core known as eddy currents and power loss due to their flow is called eddy current loss. The eddy current loss appears as heat which raises the temperature of the machine and lowers its efficiency.
3. Mechanical losses: These losses are due to friction and windage. These losses depend upon the speed of the machine. But for a given speed, they are practically constant.
7. Tell 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.
8. Do you know whats is MARX CIRCUIT?
It is used with generators for charging a number of capacitor in parallel and discharging them in series.It is used when voltage required for testing is higher than the available.
9. Tell me what are the advantage of free wheeling diode in a Full Wave rectifier?
It reduces the harmonics and it also reduces sparking and arching across the mechanical switch so that it reduces the voltage spike seen in a inductive load.
10. Tell us what are the advantages of parallel operation of generators?
1. Continuity of service
2. Efficiency
3. Maintenance and Repair
4. Increasing plant capacity
5. Non availability of single large unit
11. Do you know armature reaction?
Armature reaction is the effect of magnetic field setup by armature current on the distribution of flux under main poles of a generator. The armature magnetic field has two effects
a. It demagnetizes or weakens the main flux
b. It cross-magnetizes or distorts it.
The first effect leads to reduced generated voltage and second to the sparking at the brushes.
12. Do you know what are the different types of generators?
Generators are generally classified based on their methods of field excitation
(i) Separately excited d.c. generators
(ii) Self-excited d.c. generators
13. Please explain why do you want to leave your current employer?
To find a better job (more income), also to get more knowledge and widen my experience.
14. Explain me a difficult project and how you overcame the challenges?
I was given the to complete the water wash of compressor in 24 hrs with desired valve of conductivity. I worked continuously 20 hours to achieve.
15. Tell me what is the temperature steam turns into dry steam?
Steam a bowl of saturated temperature.
16. Explain me when will the ENGINE FAIL message appear on the PFD?
If actual thrust is less than commanded thrust during takeoff with airspeed between 65kts and V1-6kts. FCOM 1 70.20.16
17. Explain me how do handle the work pressure?
Say them that you think positive under stress which fills some energy in you and that's how you face problems.
To avoid the transmission losses.
19. Do you know who is a power plant operator?
A power plant operator is a person who operates a power plant. He has got to be good at the technical skills of using the power plant and must be equally talented in distributing the work to the other workers who are working with the power plant.
Steam should be heated to the temperature it is before making it to enter the turbine because superheated steam produces a lot of energy and also prevents the blades from rusting or damaging.
22. Tell me why are you the best Power Plant Operator for us?
Because of the knowledge I posses. Interpersonal communications, team work, leadership, courage, unselfishness, loyalty, and dependability.
23. Explain me what is your greatest strength and how do you feel it will help you in this role?
Attention to detail and problem solving with a good back to anticipate things before they happen.
24. Explain me how do you define Self Excited Generators?
A d.c. generator whose field magnet winding is supplied current from the output of the generator itself is called a self-excited generator. There are three types of self-excited generators depending upon the manner in which the field winding is connected to the armature,
(i) Series generator - , the field winding is connected in series with armature winding so that whole armature current flows through the field winding as well as the load.
(ii) Shunt generator - , the field winding is connected in parallel with the armature winding so that terminal voltage of the generator is applied across it.
(iii) Compound generator - there are two sets of field windings on each pole-one is in series and the other in parallel with the armature. A compound wound generator may be:
(a) Short Shunt in which only shunt field winding is in parallel with the armature winding
(b) Long Shunt in which shunt field winding is in parallel with both series field and armature winding
25. Do you know how do you improve Commutation?
Improving commutation means to make current reversal in the short-circuited coil as spark less as possible. This can be done using
(i) Resistance commutation
(ii) E.M.F. commutation
