Question { Essar, 31334 }

why making capacity is more than breaking capacity?

Answer

because of the inductance associated with the circuit, it
takes time to establish magnetic fields around all the
wires and whatnot. This requires extra current at startup.

Question { Samsung, 11684 }

How cn u measure to steam in kg/hr or ton/hr

Answer

we measure steam pressure in kg/sq.cm and boiler capacity
in ton/hr.

Question { BEL, 9303 }

what are the types used for alternator earthing,what will
happen if more than two alternator is working in
parallel with each having own system earthing.is there any
possibility for circulating current in between two system.

Answer

if two alternators running parallel and both alternators
neutral grounded by one earthing strip, there is chance of
circulating current. because the unbalanced current flow
through the neutral of one alt.to second alt.by the neutral.
if both alternators earthing is separate , then no chance
of circulating current.

Question { 7066 }

what is the diffrantial relay???????why we use it on the MDB

Answer

DIFFERENTIAL RELAY is used to sense generator supply in two
different locations. in generator out put leads are six. in
three phase winding- three leads of begining of coils and
three leads of ends of coils.three leads are named R,Y,B
and other three leads are R1,Y1,B1. we make star connetion
by joint R1,Y1,B1 and make neutral point by this
junction.we ground this neutral.we provide three CT'S in
RYB side and three CT'S in R1 Y1 B1 side.
if any fault occurs in winding between RYB and R1 Y1 B1 the
resultant supply operates the differential relay and the
generator stops automatically.

Question { L&T, 114979 }

How to calculate the motor winding resistance ?

Answer

disconnect the motor connections and separate the wires and
check the resistance with multi meter of all winding
separately.

Question { UltraTech, 36633 }

How to calculate kva? what is the formula.

Answer

KW = KVA X p.f
KVA= KW/ P.F
P.F= kw/KVA
KVAR= KVA.Sin theta

Question { 5641 }

How to increase the humidity content in an air?

Answer

use steam pressure spray in air handling unit after cooling
coil and heating coil. control steam pressure by motorised
valve as per your requirement.

Question { 49708 }

Why reverse power relay is used?

Answer

if two generators synchronised and are punning parallel,
the total load divided and generator takes half of the
total load upon it.
some times because of load unbalancing one generator
shifts his total load on second generator and run as a
motor . before this condition the generator is taking load
upon him and now it will became as a load and it will run
as a motor insted of generator.
in this condition the second generator winding can be
damage, so we use reverse power relay. because the
direction changed of power , so we called it reverse
power .

Question { 3961 }

In HVAC R22 gas are using for cooling but why oil are using
& which type of it is???????/

Answer

oil is using for lubrication of moving parts, like:-motor
bearing, centrifugal assy, and guide vane etc. this oil is
compressor oil.

Question { Philips, 12821 }

enlist types of dc generator

Answer

D.C.Generators are two types: 1) separately excited
D.C.Generator and 2) self excited d.c generator.
self excited generators three types:-1) series wound
generator 2) shunt wound generator 3) compound wound
generator.

Question { Marico, 16411 }

how ship earthed?

Answer

ships are earthed by MAST device. it is connected on the
top of the ship. when lighting occured the light will come
through this mast to the plate , which is mounted under the
ship.this current goes in the water , because water is good
conducter of electricity.

Question { Suzlon, 65319 }

what do you mean by leading power factor & lagging power
factor

Answer

power factor is the ratio of true power and apparent power.
when the load is inductive, the inductance tends to oppose
the flow of current, storing energy then realising it later
in the cycle. the current wave forms lags behind the
voltage wave form.
when the load is capacitive, the opposite occurs, and the
current wave form leads the voltage waveform.

Question { 16833 }

Pls say , how we calculate lux / sq.ft, which formula used
for calculation

Answer

we can calculate lux level by lux meter.

Total lumens required= A . E . D/U where,
A = surface area(sq.m)
E= illumination(lm/sq.m)
D= dipriciation factor
U= co-efficient of utilization

Question { IIT, 8341 }

what is MFD value in capacitor?I have 201 Kva load &
reactive power is 150 Kvar. so how it is calculated?

Answer

MFD means micro farad.
1 farad= 1 colomb/1 volt

Question { Siemens, 44437 }

what's float charger and boost charger? why it's used?

Answer

The difference between a float charger and a trickle
charger is that the float has circuitry to prevent
overcharging. It senses when the battery voltage is at the
maximum level and temporarily shuts off the charge (floats
voltage at zero or a very minimal charge until it senses
that the battery output voltage has fallen, then resumes
charging ). You can keep it connected indefinitely.
A trickle charger, on the other hand, will charge no matter
whether the battery is fully charged or not. So it needs to
be connected and disconnected periodically. If left in
place too long it'll eventually boil the electrolyte out of
the cells or damage the plates. Trickle chargers will work
to keep the battery charged if used once a month or so for
a day or 2, but the float chargers can be left connected
indefinitely without potential harm to the battery.
For example, a 24 volt battery pack, comprising 12 2-volt
flooded lead-acid cells, which has been deeply discharged,
would normally be restored by a boost charge of
approximately 2.4 volts per cell for a short time (perhaps
around 72 hours). Once the collective cell voltage reaches
a surface charge of 28.8 volts (2.4 volts x 12 cells), the
charge rate would be switched to the sustained lower float-
charging rate of typically 2.23 volts.
Eventually, with the Boost charge removed, the surface
charge will diminish slightly and the battery-bank voltage
will stabilise at a preset float voltage, in the case of
the example above to approximately 27 volts (2.23 volts x
12).