Basic Formula Table
Electrikgrid Website
Revised 05/11/06, J Allen
/=divided by *=multiplied by sq root=square root of…
NERC
Area Control Error:
ACE= (NIa-NIs)-10β(Fa-Fs)-Ime
Single
phase kVA= kV * amps, Single
phase kW= kV*amps * power factor
3
phase kVA= kV*amps*1.73 3 phase kW= kV*amps*power factor*1.73
Total
kVA for three banked identically rated 1 phase
transformers= 3*kVA of a single transformer
Maximum
amps= (kVA rating of equipment)/ (kV*1.73)
Maximum
transformer short circuit amps= (transformer maximum amp rating/% Z)*100
Regulator
maximum amps=(nameplate kVA of regulator)/(kV*1.73*%
regulation in decimal format)
Conversion
120 VAC secondary to primary kV:
For phase to ground
potential: primary volts= secondary
phase to ground volts PT ratio*1.73
For phase to phase
potential: primary volts= metering phase
to phase volts* PT ratio
RPM
for 60 Hz= (frequency in Hertz*120)/poles
Basic
electricity:
E/R when
I=amps, E=volts, R=Ohms resistance
Hydroelectric
highlights
1 hp= 746 watts= 0.746 kW= 33000
ft/lbs per minute
1 acre foot (AF) = 43,560 cubic
feet
cubic feet per second *
hours*0.0826= AF for given period
1 cubic foot per second (CFS)
for 24 hours = 1.98 AF
kW= (CFS*head in feet*efficiency
in decimal)/11.8
1 foot head= 0.4335 psig
Water flow through an orifice=
coefficient*opening in square feet*[sq. root (64.4*head in feet)]
1 gallon= 231 cubic inches=
0.13368 cubic feet= weight of 8.33 lbs
Fundamental
trigonometric relationships
Sin (sine)= opposite/hypotenuse; cos (cosine)=
adjacent/hypotenuse; tan (tangent)=
opposite/adjacent; c2=a2
+ b2
MVAR= sq root(MVA2-MW2)
Power factor (PF)= kW/kVA
The cosine of (amps/volts)= phase angle difference
Other:
Inches*0.0254=
meters; miles*1.609= kilometers; liters*0.2642= gallons; 1 inch Hg= 0.491 psi; watts=btu/min*17.57; kilometers*0.621=miles;
F=
(9/5*C)+32 C=
5/9(F-32)
CAUTION: THINK, BE SAFE, BE ALIVE!
SAFETY FIRST
