Specifications

Technical Information
89www.rainbird.com
TECHNICAL INFO
Hydraulic / Power Formulas
PRECIPITATION RATE IN/HR
HORSE POWER
DESIGN FORMULAS
POWER FORMULAS
V = 0.480 x Q
(ID)
2
Where:
V = Velocity in feet per second
Q = Gallons per minute
ID = Inside diameter of pipe
96.3 x GPM x 360
S x S x Sprinkler Arc
Square =
96.3 x GPM
S x 0.8 Diameter
Single Row =
96.3 x GPM x 360
S x S x 0.866 x Sprinkler Arc
Triangular =
Desired Application x 60
Precipitation Rate
Run-Time =
3ф KVA = 1.732 x FLA x Voltage
1000
1ф KVA = FLA x Voltage
1000
Ohm’s Law: V = IR
Where:
V = Voltage in Volts
I = Current in Amperes
R = Resistance in ohms
Amp Calculation
Amps = Watts / Volts
Where:
Power Factor (PF) = Power Used (Watts) or KW
Apparent Power KVA
Percent Efficiency (%EFF) = Output (Watts)
Input (Watts)
E = Volts
I = Amperes
W = Watts
RPM / RPM = Flow / Flow
(RPM / RPM) = Pressure / Pressure
(RPM / RPM) = Power / Power
Example: An irrigation pump operating at 1800 RPM
and producing 600 gpm at 120 psi is switched to
3600 RPM:
RPM / RPM = Flow / Flow
= 3600 RPM / 1800 RPM
= Flow / 600 gpm = 1200 gpm
(RPM / RPM) = Pressure / Pressure
= (3600 RPM / 1800 RPM)
= Pressure/120 psi = 480 psi
(RPM / RPM) = Power / Power
= (3600 RPM / 1800 RPM)
= Power / 60 HP = 480 HP
1 hp = 550 foot pounds per second
= 746 watts or 0.746 kW
= 1 second foot of water falling 8.8'
Water HP = GPM x TDH
3960
Where:
GPM = Gallons per minute
TDH = Total dynamic head
Brake HP = GPM x TDH
3960 x E
Where:
GPM = Gallons per minute
TDH = Total dynamic head
E = Pump efficiency
1 kilowatt (kW) = 1000 watts
= 1,341 HP
= 735.5 foot pounds per second
VELOCITY
ELECTRICAL POWER
RUNTIME
PUMP LAWS AFFINITY LAWS
ELECTRIC FORMULAS FOR CALCULATING AMPERES,
HORSEPOWER, KILOWATTS AND KVA
ALTERNATING CURRENT
TO FIND: SINGLE PHASE TWO PHASE  FOUR PHASE WIRE THREE PHASE
Amperes when “HP”
is Known
HP x 746
E x %EFF x PF
HP x 746
E x %EFF x PF x 2
HP x 746
E x %EFF x PF x 1.73
Amperes when “KW”
is Known
KW x 1000
E x PF
KW x 1000
E x PF x 2
KW x 1000
E x PF x 1.73
Amperes when “KVA”
is Known
KVA x 1000
E
KVA x 1000
E x 2
KVA x 1000
E x 1.73
Kilowatts E x I x PF
1000
E x I x PF x 2
1000
E x I x PF x 1.73
1000
Kilovolt - Ampers
“KVA”
E x I
1000
E x I x 2
1000
E x I x 1.73
1000
Horsepower E x I x %EFF x PF
746
E x I x %EFF x PF x 2
746
E x I x %EFF x PF x 1.73
746
S= Spacing