Electrical Formulas - Guardian 4389 Diagnostic Repair Manual

ELECTRICAL FORMULAS

TO FIND
KILOWATTS (kW)
KVA
AMPERES
WATTS
NO. OF ROTOR
POLES
FREQUENCY
RPM
kW (required for
Motor)
RESISTANCE
VOLTS
AMPERES
E = VOLTS
Page 1
KNOWN VALUES
Volts, Current, Power Factor
Volts, Current
kW, Volts, Power Factor
Volts, Amps, Power Factor
Frequency, RPM
RPM, No. of Rotor Poles
Frequency, No. of Rotor Poles
Motor Horsepower, Efficiency
Volts, Amperes
Ohm, Amperes
Ohms, Volts
I = AMPERES
1-PHASE
E x I
1000
E x I
1000
kW x 1000
E
Volts x Amps
2 x 60 x Frequency
RPM
RPM x Poles
2 x 60
2 x 60 x Frequency
Rotor Poles
HP x 0.746
Efficiency
E
I
I x R
E
R
R = RESISTANCE (OHMS)
3-PHASE
E x I x 1.73 x PF
1000
E x I x 1.73
1000
kW x 1000
E x 1.73 x PF
E x I x 1.73 x PF
2 x 60 x frequency
RPM
RPM x Poles
2 x 60
2 x 60 x Frequency
Rotor Poles
HP x 0.746
Efficiency
E
I
I x R
E
R
PF = POWER FACTOR