KV AND KVA

[visitor]

WHAT IS THE DIFFERENCE BETWEEN KV AND KVA ?
IS THERE ANY CONVERSION FACTOR BETWEEN THE TWO?
THANKS

 

[electricpete]

For single-phase systems
KVA = KV x Amps

For 3-phase systems:
KVA = KV x Amps *sqrt(3).

KV is the voltage as you probably know.
KVA is the "apparent power".
In my mind it's apparent because that's what you would
calculate if you only knew the volts and the amps
and not the power factor.
KVA is a little bigger
than the real power (kw). It's the square root of sum of squares of real and reactive powers.

 

what is the power consumption by a single system(load)in kw and kva? suppose we have a load of 17000w what is the equivalent kva?.

 

[electricpete]

For single-phase loads:
Power (kw) = Apparent Power (kva) * power factor
= Voltage(kv) * amps (A) * power factor
For a resistive load, power factor is typically 1.0.
For a motor load , power factor is lower than 1.0

Let's say you have a 120v motor which draws 10Amps, 0.8 power factor.

Apparent Power = 120V*10A = 1.2KVA
Power = Apparent Power * Power Factor = 1.2*0.8 =0.96KW

 

[Wirenut]

KV MEANS 1000 VOLTS.

KVA MEANS 1000 VOLT-AMPS.

VA IS SIMPLY VOLTS MULTYPLIED BY AMPS.

KEEP THE ANSWERS SIMPLE Wirenut

 

[gtf]

Could someone advise the actual effects on the ac induction motor when the supply voltage decreases and what happens when voltage increases. What happens to the motor currents and torque ?

Please provide formula if possible

Thank you.

 

[jbartos]

Suggestions:
1. To: gtf (Electrical) May 18, 2001
Could someone advise the actual effects on the ac induction motor.....
<<Regarding the ac motor, please, see my posting as a response to your posting at other place.>>
2. To: hariharasudhan (Visitor) May 14, 2001
what is the power consumption by a single system(load)in kw and kva?
<<It can be both. It depends on many factors. Many loads have kW on their nameplates, e.g. heaters, lamps, small motors, ac drives, etc. Others have kVA, e.g. motors, transformers, etc.
kVA and kW are tied by relationships posted above in most cases that do not deal with harmonics and power quality.
suppose we have a load of 17000w what is the equivalent kva?.
<<kVA = 17000 Watts x power factor / 1000>>
3. To: visitor (Visitor) May 13, 2001
WHAT IS THE DIFFERENCE BETWEEN KV AND KVA ?
<<kV is a unit or dimension for voltage, and kVA is unit or dimension for Apparent or complex power.>>
IS THERE ANY CONVERSION FACTOR BETWEEN THE TWO?
<<Yes, there is a difference since kV is a unit for voltage and kVA is a unit for apparent power. Obviously, the voltage is different from power; however, they are related by several relationships, e.g.
Power kVA = Voltage kV x Current A, or
Power kVA = (Voltage kV)**2/Impedance Z
for simple one phase (single phase) circuit and associated connected load.