Question { 5581 }

Technician A says the brake warning light is connected into
both the parking and service brake systems. Technician B
says the brake warning light will come ON only if the
service brake system fails. Who is correct?

Answer

Both are correct:

Technician A says: u can see the brake warning at both places,
that is possible.

Technician B says: warning will come at the both places if
"service brake system fails".

Question { MIT, 3044 }

WHY IS MAGNETIC NEEDLE POINTD?

Answer

This is bcz of earth N-S poles.

If u try to keep parallel two magnet bar's same poles together then u will see that one magnetic N-pole will rotate to
another's S-pole, two same type poles never close together bcz
of repulsive force.........same thing is with "MAGNETIC NEEDLE " and earth (Earth is itself a stronge magnet)

Question { ABB, 9358 }

what is the earthing condition between earth & neutral.

Answer

Voltage difference b/w earth and neutral depends upon supply voltage, load and earth pit connectivity(bcz in all same conditions except clay nature means alklye ness and dryness, the voltage diff. is always different) as i have seen in india as well as in Sudan and zambia.
this is not fixed b/w 2or3 volt.
Bcz if the supply output is open ckt then no voltage will get but as the load increases the voltage b/w earth (if earth pit are perfect) and neutral will increase as the earth potential is zero (fixed).

Question { ABB, 9358 }

what is the earthing condition between earth & neutral.

Answer

Voltage difference b/w earth and neutral depends upon the leakage current and that depends upon supply voltage, load and earth pit connectivity(bcz in all same conditions except clay nature means alklye ness and dryness, the voltage diff. is always different) as i have seen in india as well as in Sudan and zambia.
this is not fixed b/w 2or3 volt. But it must be as low as possible by making perfect earth pit.
If the supply output is open ckt(zero leakage current)then no voltage will get but with supply as the load increases the voltage b/w earth and neutral will increase as the earth potential is zero (fixed).

Question { 8629 }

Where there is voltage,there must be current.Is this right
or wrong??

Answer

I disagreed with "Magbool", He is talking "in case of open circuit,voltage is equal to emf of cell but current is equal to zero" only for an ideal condition but in practically this is not possible, Bcz a little amount of current goes in the Voltmeter circuit. To prove my statement:
If there is a current then definitely there will be a voltage across the medium (resistance). Its OK the input impedance of voltmeter is much high but practically not infinite, therefore some current will go inside the voltmeter.

Question { ABB, 29908 }

relation between flow and differential pressure.

Answer

If pressure difference is high definitely the flow will high and if DP(differential press.) became low or zero, means line is partially/ fully chocked. and as we know Flow = square root(DP.

Question { 5894 }

hello freinds what is advantage and disadvantage of plc
again dcs?

Answer

See PLC is a "Programmable Control System" as Mr. J.santosh have already explained, but DCS is "Distributed Control System" means if ur system is distributed in many controllers but operated and controlled with single SCADA then such system is called DCS.

DCS is not a feature of Hardware but is the feature of software.

PLC is faster than DCS but with less I/O handling capability.
and PLC is used only in machine automation type system (like in Power plant for soot blowers, Cooling sys., in Cement plant RABH, Bag filter, Air blasters, Lubrication system, Girth gear etc).

DCS is mainly used in process.

Question { Electrical Tech, 32407 }

what is the use of earthing ?

Answer

Earthing is nothing but is used to remove unwanted/ harmful current/ Voltage by sending it to earth via. earth pit, either it come in the body of any instrument (washing machine, Freeze, AC or any lathe machines, electrical motors..) or in the shield of the signal cable via interference.
This is also known with different-2 names.
Like: Electronic earthing, panel earthing, system earthing, Instrument earthing, Shield earthing...... .

But the purpose is same....

This is not only to protect the Human and equipment but also for better communication in case of 4-20ma, 0-10V signals.... removed by using shielded cables with one end earthed.

Question { TNEB Tamil Nadu Electricity Board, 54345 }

what is the use of megger? and types

Answer

I agreed with Mr. Sri Valli.