KVAR RATING CALCULATOR,CAPACITOR BANK SIZE CALCULATION

-
Image
  Determination of Required Capacitor Rating by measurement 3 Methods are used. 1. Measurement with current and power factor 2.Measurement with recording of Active and Reactive power. 3.Measurement by Reading Meters . 1 . Measurement with Current and power factor The active power P is calculate from the measured voltage V ,apparent current Is and Power Factor P=√3*Voltage*apparent Current*cosψ *10^-3 If the desired power factor cosψ has been specified, the capacitor power rating can be calculate from the following formula: Qc = P. (tan ψactual - tanψ desired) Let's See the Example Measured Apparent Current Is : 248 Amps Power Factor cos ψ1 = 0.86 Desired Cos ψ2 = 0.92 Voltage V :397 V p=√3 * 397 * 248 * 0.86 * 103 P = 146.6 KW Qc= P. (tanψ actual - tanψ desired) = 146.6(0.59 - 0.42) = 24.9 KVAR
Post a Comment

UNCERTAINTY OF MEASUREMENT OF ANALOGUE PRESSURE GAUGE

-

 

SOURCE OF UNCERTAINTY OF PRESSURE GAUGE

  1. Repeatability of the unit under test.
  2. Resolution of UUT
  3. Expanded Uncertainty of Master Instrument
  4. Hysteresis Error
  5. Drift of the Master Instrument\
  6. Uncorrected Error of Master Instrument



  Calibration Result

 

 1.0  Repeatability of the instrument (U1)

Uncertainty from the repeatability  = 0.05774 bar
2.0  Resolution of UUT (U2)
        Resolution of UUT  = 1 bar
     Uncertainty from the resolution of the UUT =  
    
     =(1/5)/sqrt (3)
                                         =0.1154700 bar                              
 3.0  Uncertainty of Master Instrument (U3)

Expanded Uncertainty of Master Instrument  = 0.025 % FSD

Uncertainty of Master Instrument =

                                                                                                                        =((0.025*40)/100)

                                                 = 0.01

                                                                  =0.01/2

                                                                  =0.005 bar

4.0 Hysteresis Error (U4)

.
Uncertainty of Hysteresis error of Instrument from the upward and downward direction = 

                                        = 0.00 bar
5.0  Uncertainty of Master Instrument Drift (U5)

Uncertainty from the Drift of Master Instrument  =


=(0.01/3)/sqrt (3)

                              =0.0019245 bar

 6.0  Uncorrected Error of Master Instrument (U6)

Uncorrected Error =  Maximum error found in the calibration  Certificate 


Uncertainty of uncorrected error of Master  =

        

=


                            = (0.009 /2 )/sqrt(3)

                 = 0.002598 bar


Combined Uncertainty (uc(x)) =                                               

                                             

                           =√(0.0577350²+0.11547²+0.005²+0.00²+0.002598²+0.00192²)


                           =0.1292

Expanded Uncertainty (ue(x)) (±) =  (uc(x)) *k

The statement of uncertainty is reported with a coverage factor of k=2, which indicates approximate 95% confidence 
                                                  
                                                    = 0.1292*2

                                                    = 0.2584


                              =   Significant figure rounding (0.2584)


                
                              =0.26 bar





 

             
      










Comments

Post a Comment

Popular posts from this blog

TOLERANCE OR MAXIMUM PERMISSIBLE ERROR OR ACCURACY OF VERNIER OF DIGITAL CALIPER AS PER BS EN ISO 13385-1:2019

-
 Calliper  Measuring instrument which evaluates a dimensional quantity of an internal or external feature of the basis of opposing contact from the movement of a slider with a measuring jaw, moving relative to a measuring scale on rigid beam and to a fixed jaw. Maximum permissible error (MPE) values apply to any indication permitted for use of calliper as defined by the manufacturer and when used in accordance with the manufacturer's recommendation .The MPE Values cannot be smaller than the digital step or the scale interval on the circular scale or vernier scale There are mainly three Error are consider in the calliper .Partial Surface contact error , E ( limited by   E MPE ) Shift Error ,S (limited by  S MPE ) Line Contact Error DEFAULT MPE (Maximum Permissible Error ) for metrological characteristics If no MPE values are otherwise stated then the values in tables apply for callipers with a measuring range up to 1000 mm and with analogue scale interval or digital step of 0.01 mm
Read more

HOW TO CALCULATE THE UNCERTAINTY BUDGET OF pH METER.

-
Image
1. SOURCES OF UNCERTAINTY A. Repeatability (Type A) B. Buffers (Type B) C. Resolution of pH meter (Type B) D. Linearity (Type B) E. Temperature (Type B) 2. Quntification of Sources of Uncertainty A. Repeatability (Type A)                 Repeatability calculation (Type A Uncertainty)                             Formula / Expression of find the Repeatability (Standard uncertainty) Mean = AVERAGE(B4:B13) (X - Mean) = $B4-$C$4                   =UUT Value - Mean (X - Mean)^2 = ($D4)^2                             =( UUT Value - Mean)^2     Standard Deviation = STDEV(B4:B13)    Repeatability (Standard Uncertainty) =  F4/SQRT(10)                                                                                    =Standard Deviation / square root (number of Sample) B. Buffers: Following Buffers are used in Calibration of pH Meter: a) 4.01 with ± 0.02 uncertainty declared by manufacturer. b)7.00 with ± 0.01 uncertainty declared by manufacturer. c) 10.01 with ± 0.03 uncertainty declared by manu
Read more

Estimation of Uncertainty in Hardness Measurement & Maximum Permissible Error of Brinell Hardness Testing Machine As Per ISO 6506-2 & ASTM E10-15

-
Image
Source of Uncertainty of Hardness Measurement Certified Value of CRM Determine the User Machine Repeatability Assessment according EN ISO 6506 Uncertainty from the Measured Material. Resolution of the Indentation diameter measuring device.                            1. Certified Value of CRM       Xcrm = 222 HBW 10/3000    Ucrm    = 土 1.4 HBW  (2σ Uncertainty) 2 . Determine the User Machine Repeatability       H₁ = 221     H₂ = 220      H₃ = 220      H₄ = 221      H₅ = 220     Mean = 220  HBW                      b )  Repeatability of  Hardness Measurement                      H₅ = 220                          H₁ = 221                               = -1 HBW                    (C) Standard Deviation                                                                           =0.55 HBW   3. Assessment according EN ISO 6506           a)  The error ( E) of the testing machine                                                                           = 222 - 220                                 
Read more