Question { 10614 }

What will happen if I apply DC to AC transformer? please
send detailed answer at habib_rahman_habib786@yahoo.com

Answer

Short Answer: Nothing will happen

Long Answer: Transformer reacts in AC since the working principle is induction by primary coil to the secondary coil (giving step-up or step down VOLTAGE, depending on number of coil turns in them)

This induction happens if you have rate of change in voltage i.e AC, or at the start of your termination of your DC (from 0V to whatever your DC voltage).

Therefore, in your case, the transformer will act as a transformer only at the beginning of the DC connection (well, think: when you disconnect also...)

During steady state when the DC has stabilized, nothing will happen because there's no rate of change in voltage anymore.

Question { 5080 }

shall we use a machine having 60Hz frequency in india ? why?

Answer

in addition to #1 answer, if you're using 60Hz motor on 50Hz, the speed will be rated based on 50Hz and you may loose the designed torque hence require more current to run

Question { Godrej, 6303 }

How to connect surge arrester with equipment?

Answer

Depending on the configuration, the surge protection device (SPD) may be connected in shunt mode or in series. usually, the latter has a set of surge diverting components and a set of high frequency filter to further attenuate high frequency component of lightning surge current. The simpler one;the shunt type; usually has simpler surge diverting component such as Metal Oxide Varistor (MOV) and/or Zener Diode and/or Gas Discharge Tube (GDT).

You will now how to connect by looking of the cables poking out of the SPD. If you have (for single phase) only a set of L,N,G, it's usually shunt type. If you see 2 sets, well of curse it's the series one. Hint: look at the diagram of connection supplied with the device.

Be extra cautious when you do termination of the grounding cable though. From my experience, the grounding termination (cable length, bending,size and route) is very important regardless of how good your SPD you choose.

Question { ABB, 21099 }

What is the meager?

Answer

Most likely the misspelled "Megger". Megger is a company whose Insulation Resistance meter is so well known; people usually associates any insulation resistance meter as 'megger tester'.

Question { Essar, 2062 }

What is cp system and why is it required.?

Answer

If you are referring to cathodic protection, here is my simplified answer..

Cp is needed to protect metal from surface corrosion. By using sacrificial anode you are ensuring the protected metal does not corrode until all the anode used up (exhaused. From corrosion)

If you use impressed current cp (iccp), you are 'reversing' the natural process of metal reduction (-hence corrode), protecting the metal from corroding.