3 phase motor amps calculation

3 phase motor amps calculation

If we know the watts rating and efficiency of the motor then we can calculate the amperage of the motor or current rating of the motor by using the following formula. the following chart is useful for both DC and AC current motors. mostly single phase and 3 phase motor amps calculation are used in industry. the following table is useful in to convert horsepower to amps & to convert motor hp to amps.

3 phase motor amps calculator

Enter phase of supply and load of motor and get full load ampere of motor-

3 phase motor amps calculation & formula charts

To Find…Direct CurrentAlternating Current (Single Phase)Alternating Current(Two-Phase* Four-WireAlternating Current(Three Phase)
Amperes when Horsepower is known HP x 746
────────
E x EFF
HP x 746
────────
E x EFF x PF
HP x 746
────────
2 x E x EFF x PF
HP x 746
───────────
E x EFF x PF x 1.73
Amperes when Kilowatts are knownKW x 1000
────────
E
KW x 1000
────────
E x PF
KW x 1000
────────
2 x E x PF
KW x 1000
───────────
E x PF x 1.73
Amperes when “KVA” is known  ─KVA x 1000
────────
E
KVA x 1000
────────
2 x E
KVA x 1000
───────────
E x 1.73
Kilowatts E x I
────────
1000
E x I x PF
────────
1000
I x E x 2 x PF
────────
1000
E x I x 1.73 x PF
───────────
1000
Kilovolt-Amperes “KVA”   ─ I x E
────────
1000
I x E x 2
────────
1000
E x I x 1.73
────────
1000
Horsepower (Output)E x I x EFF
────────
746
E x I x EFF x PF
────────
746
I x E x 2 x EFF x PF
───────────
746
E x I x EFF x PF x 1.73
───────────
746

Where E = Voltage, I = Amps, PF = Power Factor, EFF = Efficiency, HP = Horsepower

How to Convert Horsepower to Amps

usually single-phase motor or 3 phase motor is used in industries. in the case of single-phase, motor case rated ampere can be calculated using the following formula. single phase motor amps calculation

                            HP × 746
Amps = ──────
V × η × PF

Let us see how we calculate the above formula-

Convert Horsepower to Watts

The first step to convert HP to amps is to convert HP to watts. Since 1 HP is equal to 746 W simply multiply the horsepower by 746 for this conversion.

Watts = Horsepower × 746
as we know all motors are not 100 % efficient efficiency usually from 70 % to 99 %.
Hence Watts = watts/ η

Convert to Amps

After the power has been converted to watts, use Watt’s Law formula to find current in amps.

Amps = Watts ÷ Volts

if pf is known then using above formula

                            HP × 746
Amps = ──────
V × η × PF

similarly for 3 phase motor amps calculation, the current rating can be calculated by using the following formula. all about convert horsepower to amps & to convert motor hp to amps.

                              HP × 746
        Amps =     ─────────
                          1.73 x V × η × PF
https://www.electricalsells.com/how-to-calculate-kva-size-of-transformer/

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