Power RelationshipsPower Relationships

P = watts

S = volt-amps

Q = volt-amps of reactance

Power RelationshipsPower Relationships

Resistance (R).

Inductance Reactance (XL)

Capacitance Reactance (Xc)

Reactive PowerReactive Power

Rate at which energy is being stored and returned to the ckt Inductance temporally stores energy Capacitors temporally store energy

Measured in Volt-amps of Reactance Units VARS

Symbol is Q

Q=Ex x Ix

True PowerTrue Power

Rate at which energy is dissipated or consumed in the CKT The load of the ckt ex motor, light

Measure in Watts Units are W

Symbol is P

P=Er x Ir

Apparent PowerApparent Power

Combined effect of Power and Reactive Power

Measured in volt-amps Units VA

Symbol is S

S=E x I

Power Factor Power Factor

Ratio between power and apparent power

P.f. = P/S

Require the angle (θ) Angleθ = cos-1p.f

Power TrianglePower Triangle

POWER TRIANGLE

LAGGING WATTS

VO

LT

AM

PS

RE

AC

TIV

E

WATTS

VO

LT

AM

PS

CA

PA

CIT

IVE

POWER TRIANGLE

LEADING

P =

Q =

P =

Q =