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  • in reply to: electrical question #12112
    admin
    Keymaster

    Capacity of the generator should be greater than total peak hour powerconsumption.

    in reply to: three phase power consuption calculations #12110
    admin
    Keymaster

    vittal said:

    Yoy may know

     

    P=1.732(root 3) x VXIXPOWER FACTOR

    AND 1HP=?wATTS

    NOW YOU MAY FIND YOUR CONSUMPTION


    By just knowing the connected load in HP you can not calculate what is the consumption in kWh.It depends on loading. Otherwise 1000HP = 746 kW and if it is fully loaded than it will consume 746kWh i.e 746 units in one hour

    in reply to: Power Transformer #12107
    admin
    Keymaster

    Hello, no it s not normal at all, try to consult with manufacturer there is some routine test that they could investigate your transformers during this tests.

    Sincerely,

    S.Solimani

    in reply to: power factor improvement #12106
    admin
    Keymaster

     
    It is physics and has do with 2nd year electrical vector diagrams on resistance inductance and capacitance
     

    The statement is correct resistive is the bottom of the triangle inductive goes up and capacitive down which the total load determines the angle which is the power factor (PF).
     

    The only way to reduce power factor (PF=cos(Pheta)) that is inductive (motors) is to add capacitors or ballast with capacitor in them as it is an additive relationship base on the angle of usage.
     

    This is very complicated but I hope that put it in laymen’s terms.
     

    in reply to: Thermal O/L Relay setting #12105
    admin
    Keymaster

    hi erikench,

                thanks for information. i want to know whether class of insulation will affect the  overload setting .

    in reply to: transformer losses #12104
    admin
    Keymaster

    anil i agree with you.

    But i think to know the full load losses you have to go for open ckt test (i.e. iron losses) and short ckt test (i.e copper losses).then to know tfransformer loss at any load= iron loss + copper loss at that load.

    e.g.  copper loss at 50% load = ( 50% 0f full load current)2*R

                                                  =(I/2)2*R

                                                  =I2R/4 

    in reply to: transformer losses #12101
    admin
    Keymaster

    Hi,

    Look for Transformer Test report. It will have Iron losses which will remain almost constant through out the loading cycle. Then look for efficiency on the name plate. This corresponds to full load. Now calculate the full load losses. Example if 1000KVA transformer efficiency is 98% then the losses are 2% i.e. 20KW. If the Iron Losses is indicated as 2KW, then the copper losses are 18KW. Now the copper losses are proportional to square of current. Therefore at 50% load copperlosses will be 0.5 sqare times the full load copper loss. i.e. 0.25X18=4.5KW. Therefore at 50% load you will have 6.5KW losses. If you dont know what is the Iron losses of the transformer, then see the noload power consumption of the transformer, it will  be very close to iron losses.  

    admin
    Keymaster

    this is ok.. but you should have given a updated symbol list..

    in reply to: cable size & material vs current capacity #12097
    admin
    Keymaster

    hei there i would like to learn some basics of grade three please

    in reply to: three phase power consuption calculations #12096
    admin
    Keymaster

    just ask the technical question dear …..its depends on the motor location from power source.but I think u want what size of cable required for this rating ….may be …so the current consumption for 100 kw motor is

    100= 1.732x415x0.8x I

    I =100000/1.732x415x0.8

    I= 100000/575.024=173A

    in reply to: know about kvarh in meter #12095
    admin
    Keymaster

    main difference between three phase and single phase energy meter .The CT ratio and PT  are connected in 3 phase system for measuring the current and voltage simultaniousely.whereas in single phase no need to connect such things.KVRAH is the reactive power taken by transformer and kiosk unit for itself.for the modifying of this power factor we are connected the capacitor bank to this equipments so it may inductive power or capacitive power so it should be the express in capacitive and inductive respectively.

    admin
    Keymaster

    If you have pf  0.99  or more that is mean you are  improve the main electric network , and the company of electruc  should give you the bonus for that .

    and you have also avery emportant  advantage  , your  load Ampere ,ll be decrease that is mean you can add more load and that is mean also  your panel and circuit braker ,ll be  work at the good  status >

     

    Eng.   Ali Younes

    in reply to: How to work the M C B ? #12092
    admin
    Keymaster

    MCB is miniature circuit breaker which is thermal oprated

    and use for short circuit protection in small current

    rating circuit. MCCB moulded case circuit breaker and is

    thermal operated for over load current and magnetic

    operation for instant trip in short circuit condition.under

    voltage and under frequency may be inbuilt. Normally it is

    used where normal current is more than 100A.

    MCB – MINIATURE CIRCUIT BREAKER

    MCCB – MODULE CASE CIRCUIT BREAKER

    MCB RATING : 63 AMP (MAXIMUM) i.e. in the form of tpn(

    THREE PHASE + NUETRAL)

    MCCB _ 63AMP (min.)

    MCB IS USED WHERE LOAD IS LOW BUT MCCB IS USED WHERE LOAD

    IS HIGH AND USE AS INCOMER.WHILE THE MCB IS USED FOR

    OUTGOING.

    in reply to: How to work the M C B ? #12090
    admin
    Keymaster

     RCCB

    Residual Current Devices (6GDRC2)


    6GDRC2 RCCB/RCD

    The flow of current through electrical facilities always involves risks. Poorly insulated equipment, faulty wires and incorrect use of an electrical devise cause currents to flow through the wrong path (i.e., through the insulation) to the earth. This current is called ‘Leakage Current’.

    Earth Leakage is an electrical hazard and is responsible for electrical shocks and fire risk. Earth Leakage and its associated hazard can be prevented by residual current device (RCD), similar to that of a residual current circuit breaker (RCCB), also popularly known as Earth Leakage Circuit Breaker (ELCB).

    Features

    – Simple and Robust operating mechanism.
    – Rotary handle with ON/Off indication
    – Dual termination for Bus Bar as well as cable connection
    – Advance Neautral
    – Test Button for regular inspection

    you can get more at this link

    http://www.mcbrccb.com/ProductShow/Residual-Current-Devices_ID21.html

     

    What is the difference between MCB & MCCB, Where it can be used,

    MCB is miniature circuit breaker which is thermal oprated
    and use for short circuit protection in small current
    rating circuit. MCCB moulded case circuit breaker and is
    thermal operated for over load current and magnetic
    operation for instant trip in short circuit condition.under
    voltage and under frequency may be inbuilt. Normally it is
    used where normal current is more than 100A

    
    

    
    
    MCB - MINIATURE CIRCUIT BREAKER
    MCCB - MODULE CASE CIRCUIT BREAKER
    MCB RATING : 63 AMP (MAXIMUM) i.e. in the form of tpn(
    THREE PHASE + NUETRAL)
    MCCB _ 63AMP (min.)
    MCB IS USED WHERE LOAD IS LOW BUT MCCB IS USED WHERE LOAD
    IS HIGH AND USE AS INCOMER.WHILE THE MCB IS USED FOR
    OUTGOING.

    in reply to: Transformer capacity #12081
    admin
    Keymaster

    power = 1.73 * V* I

    V = 380 v

    I = ?

    power  = 315 kva  =  315 * 1000  = 315000 va

     

    I =  power /  1.37 * v =  315000/1.73 * 380 = 315000/657.4 = 479.16 A

     and from my experience  you can  know the Ampere direct by this

    if you have   KVA     and output  volt is  380

    you can    do that   

     KVA *  1.5 =  Ampere

    if you have  the power be  KW  you can do  that

    KW *  2 =  Ampere

    about your load  and you  hvae  pool pump motor  3 phase

    you must know her we have  a  power factor not  unity

    and you must make a palance on the three phase

    Engniee

    Ali  younes

Viewing 15 posts - 211 through 225 (of 508 total)