NPSH is net positive suction head of a pump. For 
centrifugal pumps, it is calculated as follows:

NPSHa = Atm. pr. + static head - vapour pressure - pressure 
loss in the suction piping - pressure loss due to the 
suction strainer.

NPSH is the acronym of Net Positive Suction Head, there r 2 
NPSH one is NPSH(a) and NPSH(r) i.e., NPSH available and 
required. Always NPSH(a) should be higher than the NPSH(r) 
this NPSH(R) will be determined my the pump manufacturer 
itself.
 
TO calculate NPSH(a)
NPSHa = Atm. pr.acting on the liquid + static head - vapour 
pressure of the liquid- pressure 
loss in the suction piping - pressure loss due to the 
suction strainer.

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the material cold rolled grain oriented is used in 
transformer core,its the aluminium material...advantages is 
minimise the iron losses,as well as minimize the eddy 
current losses...

I DONT KNOW ABT THE CRNO,BUT I KNOW ABT THE CRGO-IS COLD 
ROLED GRAIN ORIENTD,ITS THE MATERIAL USED IN THE 
TRANSFORMER WINDING....

CATHODE RAY NEGLECT OPTICALS,

I KNOW ABT THE CRGO-IS COLD 
ROLED GRAIN ORIENTD,ITS THE MATERIAL USED IN THE 
TRANSFORMER WINDING....

crgo is COLD ROLLED GRAIN ORIENTD, it is core material of x-
mer. it is used to minimize hyteresis losses.

CRGO - Cold Rolled Grain Oriented is the material used for
Transformer Windings.

CRNO - Cold Rolled Natural Oriented is the material Used for
Low quality Transformer winding constructions.

CRGO & CRNO are both  electrical steel grades used for 
stampings & cores of electrical Transformers & other 
electrical appliances. 
CRNO is cold rolled Non Grain Oriented steel laminations , 
thickness available is not less than .50mm as compared 
to .27 of CRGO, & Hence the losses in CRNO are more than 
four times of CRGO.CRNGO Non oriented fully processed 
steels are iron-silicon alloys with varying silicon 
contents and have similar magnetic properties in all 
directions in the plan of the sheet. They are principally 
used for motors, generators, alternators, ballasts, small 
transformers and a variety of other electromagnetic 
applications.  

WHERE AS CRGO is used for Distribution as well as Power 
Transformers due to its low loss characteristics.
CRGO or Cold Rolled Grain Oriented Steel is available in 
various grades (generally called M3, M4, M5 & M6). Major 
international standards such as Japanese (JIS), American 
(ASTM), German (DIN) and British Standards are AVAILABLE 
which specify grade, thickness, Watt Losses and Magnetic 
Flux density.Conventional CRGO materials (M4, M5, M6) are 
used regularly for cores in Transformers.

We use in star connection in seconday connection becouse 
need neutal point in load sied( some load supply need 3 
phase and some need single phase)but it is remember that 
only star connection use in distrubution side transformer.

we dont need nuetral at primary side but it is needed at 
sec. side because some loads of 3 ph and single phase loads 
required nuetral.

Star connection having multiple option of voltages, and 
availability of neutral point makes useful for earth fault 
relay operation.

Delta connection having requirement of 3 conductors and 
itself is long distance, with less current and higher 
voltage.  So economical way is delta at high voltage side 
and star at low/ or consumer end.

i am need for allthe technical qouestions and answers.

We could define the reactive power if we how it generates 
as follow.
All inductive (i.e. electromagnetic) machines and devices 
that operate on AC systems convert electrical energy from 
the power system generators into mechanical work and heat. 
This energy is measured by kWh meters, and is referred to 
as “active” or “wattful” energy. In order to perform this 
conversion, magnetic fields have to be established in the 
machines, and these fields are associated with another form 
of energy to be supplied from the power system, known 
as “reactive” or “wattless” energy.

THE POWER WHICH REAL UTILISATION OF THE MOTOR R OTHER 
EQUIPMENT CALLED AS ACTIVE POWER.BUT THE POWER CONSIDERING 
WITH LOSSES LIKE IRON LOSS,CU LOSS,FRICTION LOSS WEAR TEAR 
LOSS COMBINING THIS LOSSES WITH THE ACTIVE POWER CALLED AS 
REACTIVE POWER,ITS  SIMPLY SAY THE POWER DELEVARED IN THE 
OUTPUT...
IT CAN CONTROL BY AVOIDING ALL THIS LOSSES

We can control the power factor by switch on and off the 
capacitor. Reactive power is nothing but capacitive power. 
by using capacitive power continuosly the winding, core 
gets heat and it will damage the equipment.  
KVA= KW+KVAr

KVA---- Apparent Power
KW----- Active Power
KVAR--- Reactive Power

Reactive Power is full of losses. If we use any electrical 
equipment automatically reactive power obtained due to core 
losses and iron losses

the two types of earthing is used: 1. pipe type earthing
                                   2. sheet type earthing
NOTHING WILL HAPPEN WHEN TWO ALTERNATORS ARE WORKING 
PARALLEL WITH EACH HAVING ITS OWN EARTHING.
 NO THERES NO POSIBILITY OF CURRENT CIRCULATION.

in transformer cu loss depends on current and iron loss on 
voltage.Hence total loss depends on volt-ampere(VA) and not 
on phase angle between voltage and current.Thats is why 
rating of transformer is in KVA.

the power factor of the loads connected in transformer are 
not same.

The rating of any machine depends on the factor that always 
remain same at any condition. In case of a transformer the 
multiplication of voltage and current for primary and 
secondary side remain the same at all load conditions. so 
the transformer rating denoted as VA.

THE POWER FACTOR OF A TRANSFORMER FEEDING THE LOAD 
DEPENDS ON THE NATURE OF THE LOAD; HENCE THE ACTIVE(P) AND 
REACTIVE(Q) POWERS SUPPLIED BY THE TRANSFORMER MAY CHANGE 
FOR A FIXED APPEARENT POWER(S). 
   HENCE THE TRANSFORMER RATING IS ALWAYS SPECIFIED IN KVA 
AND NOT IN KW OR KVAR AS THEY CHANGE AS PER THE LOAD 
CONNECTED TO THE TRANSFORMER.

i can not reply

A pump is an equipment used to lift a liquid from one 
elevation to another elevation.  Motor is the equipement 
used to provide the power to rotate the internals of the 
pump.

PUMP AND MOTOR ARE WORKING UNDER THE SAME 
PRINCIPLES.FARADAYS LAW OF ELECTROMAGNETIC INDUCTION.


WHERIN A PUMP HAS A IMPELLER CONNECTED TO THE SHAFT WHICH 
CAN DRIVE A LIQUID TO A CERTAIN DISTANCE.


WHERERIN A MOTOR OUTPUT SHAFT IS CONNECTED TO THE 
SPROCKET ,,ETC WHICH CAN DRIVE A CONVEYOR OR PULLEY OR SO...

one of reason may be the threshold value

the lowest value is not 0 to create a difference in between
broken ckt or any other error in ckt and actual min current
value. 
b'coz for broken ckt or any other fault in ckt the current
o/p will be 0. means no current. but when it is 4 , then it
is the min o/p of the ckt and the ckt is running properly
both is confirmed. 
the upper limit is a conventional one, no such reason behind
it. but it is a value  practically can be achieved by the
designer easily. 
4-20 ma could be taken it is followed by all manufacturers.

The minimum value is 4 mA is because to avoid any confusion
of out put at lowest value.

4 milliamp is used as span lower limit, because some 
 elements on the loop require power from the loop and
 therefore a minimum level of power must be available

1. to obtain live zero
2. noise reduction
3. no current drop
4. longb tranmission

4-20mA :-
          * Easy to find the open circuit(because this 
signal level starts from 4mA, if the circuit in open the 
output shows 0mA, so we can find easily the open circuit).

          * Easy 0 to 100% segregation
4mA  - 0%
8mA  - 25%   12mA - 50%  
16mA - 75%   20mA - 100% 

          * All manufacturer following the same standard.

0-20mA :-
         * If it starts form 0mA, not able to find open 
circuit easily.

3-15mA :-
         * Less linearity, because 3mA is 0%, 15mA is 100% 
so the deviation b/w 3-15mA is lesser than 4-20mA, So that 
it reduces the accuracy of the measurement. 



So that 4-20mA is preferred over 0-10v