3 Phase Current Calculation w.r.t Hp

[gravi]

Dear Folks,

What is the formula to calculate Power consumption on each phase for a 3 phase motor with respect to Hp, when connected as mentioned below.

• 1. Direct On-Line
• 2. Star - Delta

Thanking you,
Ravi Kumar Gangumolu.

 

[Venkadesh_M]

What do u mean? Power consumption on each phase and Hp both denotes the power and single phase power is 1/3 times of total power..

 

[chuckey]

1 HP = 746 watts. Star/delta wound motors trade voltage for current, same power in, different voltages and currents. Because not all the current flowing in a three phase motors is actually contributing towards the power of the motor, the current is 1.732 higher then expected. i.e. 750W single phase 250V motor, current = 750/250 = 3 A. If its a 250V three phase motor, current is 750/3 = 250 W per winding, or 250/250 = 1 A or 3 X 1.732 total.
Frank

 

[gravi]

What do u mean? Power consumption on each phase and Hp both denotes the power and single phase power is 1/3 times of total power..

Dear Venkadesh,

1 Hp motors consume different power and 3 Hp motors consumes more power than that of 1 Hp motor, My question is what is the formula to calculate power consumption on each phase.

Thanking You,
Ravi Kumar Gangumolu.

- - - Updated - - -

1 HP = 746 watts. Star/delta wound motors trade voltage for current, same power in, different voltages and currents. Because not all the current flowing in a three phase motors is actually contributing towards the power of the motor, the current is 1.732 higher then expected. i.e. 750W single phase 250V motor, current = 750/250 = 3 A. If its a 250V three phase motor, current is 750/3 = 250 W per winding, or 250/250 = 1 A or 3 X 1.732 total.
Frank

Dear Chuckey,
1 HP = 746 Watts that is fine that is total Power consumption on all the three phases, How to calculate power consumption w.r.t each phase.

 

[Venkadesh_M]

I think you are asking current,

in 3phase induction motor in one phase,

1 Hp 1.5 A,
2 Hp 3 A
that is the way to calculate it..

 

[chuckey]

I think you are asking current,

in 3phase induction motor in one phase,

1 Hp 1.5 A,
2 Hp 3 A


that is the way to calculate it..

All depends on the system voltage!!!
Frank

 

[gravi]

Dear Venkadesh,
I am asking about, Current consumption w.r.t Phase, As Mr. Chuckey said that depends upon Voltage, How to calculate Current consumption w.r.t Phase.

Thanking You,
Ravi Kumar G

 

[Venkadesh_M]

All depends on the system voltage!!!
Frank

Il = P/ (√3 Vl) assuming power factor is unity
Vl - line voltage
Il - line current
p - 3 phase power in watts...

I shortly defined for 415V line voltage in India...