Question { Emerson, 9888 }

How we can calc. the Backup time of a battery Bank???

Answer

Hi Krishna,

V HV AN 65AH 32 No's of Batteries connected 60kva UPS,

What will be the full load backup time???

Question { 14615 }

To measure insulation resistance of 11KV cable between core
& armour, what should be the test voltage & duration?

Answer

To measure insulation resistance of 11KV cable between core
& armour,

Test voltage is 28KV(RMS Value)
Duration is 300 Sec...

Question { 4417 }

I have draw the 350A DC current, so what is the size of
cable i can use? Give me the answer with formula

Answer

Pls Provide me the following details:-

1. Rated Current.
2. Capacity of Protective Circuit Breaker used.
3. Total Length of cable.
4. Total voltage drop.
5. Laying Method.i.e. underground,in conduit,in trays etc.
6 No. of cables.i.e. grouping factor.
7. Ambient Temperature of installed area.
Temperature Correction Factor to be applied.
8. Type of cable. i.e. singel core,multicore,PVC insulated,
Armoured, XLPE insulated etc.

Question { 5345 }

what is use of thermistor ?

Answer

Thermistors are widely used for simple temperature
measurements.

They're not used for high temperatures, but in the
temperature ranges where they work they are widely used.

Question { KPTCL, 21148 }

define frequency ?

Answer

The number of cycles per unit of time is called the
frequency. For convenience, frequency is most often
measured in cycles per second (cps) or the interchangeable
Hertz (Hz)...

Question { 7314 }

WHAT IS MEANT BY vfd(VARIABLE FREQUENCY DRIVE )HOW CAN WE
APPLY VFD TO MOTOR ? I WANT FULL DETAIL IF ANYBODY KNOW THE
WEBSITE FOR THAT PLZ SEND .THANK U

Answer

Hi,

Pls find the bellow link,

http://en.wikipedia.org/wiki/Variable-frequency_drive

Question { 23475 }

how we can improve P.F. by using capacitors ?

Answer

Hi,

Pls find the bellow link,

http://en.wikipedia.org/wiki/Variable-frequency_drive

Question { 23475 }

how we can improve P.F. by using capacitors ?

Answer

Hi Sorry Ramya,

Wrong Answer...

Question { 23475 }

how we can improve P.F. by using capacitors ?

Answer

When the need arises to correct for poor power factor in an
AC power system, you probably won't have the luxury of
knowing the load's exact inductance in henrys to use for
your calculations. You may be fortunate enough to have an
instrument called a power factor meter to tell you what the
power factor is (a number between 0 and 1), and the
apparent power (which can be figured by taking a voltmeter
reading in volts and multiplying by an ammeter reading in
amps). In less favorable circumstances you may have to use
an oscilloscope to compare voltage and current waveforms,
measuring phase shift in degrees and calculating power
factor by the cosine of that phase shift.


Hi more details Pls go through the following links:-



http://www.elec-toolbox.com/usefulinfo/pfcorrection.htm

http://www.pfc-engineering.com/

Question { 23475 }

how we can improve P.F. by using capacitors ?

Answer

Welcome.........

Question { 23475 }

how we can improve P.F. by using capacitors ?

Answer

Hi Ramaya,

To Calc. the required KVAR for desired load to improve the
Power Factor,

Pls find the following link which contains the Calc. Table:

http://www.nepsi.com/kvars_required_calculation.htm

Question { 23475 }

how we can improve P.F. by using capacitors ?

Answer

Welcome Senha....t

Question { 23475 }

how we can improve P.F. by using capacitors ?

Answer

Hi Senha,

My number is 9019944592...

Question { 23475 }

how we can improve P.F. by using capacitors ?

Answer

Hi Ramya :)

Pls find the bellow links:-

For DC Machines:-
http://www.reliance.com/mtr/mtrthrmn.htm

For DC Motors:-
http://ecmweb.com/ops/electric_direct_current_motor/

Question { 23475 }

how we can improve P.F. by using capacitors ?

Answer

Your most welcome...