In order to calculate the current from the horsepower and voltage, you must also know the efficiency of the circuit. Multiply the amount of horsepower by 746. For example, if you had 4 hp, you would get 2,984. Divide the result from step one by the voltage.Click to see full answer. Keeping this in consideration, how much current does a 1 hp motor draw? 1 HP = 746 Watts. If you put P= 746 Watts in above formula, you will get rated or full load current of the motor, actual current may vary from this depending on the loading of the motor.Also Know, what is meant by 1 ampere? An ampere is a unit of measure of the rate of electron flow or current in an electrical conductor. One ampere of current represents one coulomb of electrical charge (6.24 x 1018 charge carriers) moving past a specific point in one second. The ampere is named after Andre Marie Ampere, French physicist (1775-1836). Subsequently, one may also ask, how do you calculate the current of a 3 phase motor? Arrange the equation for three-phase power to solve the current (amps): Current (amps) = power (watts) ÷ voltage (volts) ÷ square root of 3 (1.732) ÷ power factor; I = P ÷ (V_1.How many amps does a 1.5 hp motor draw?The 1.5 HP Baldor motor that turns at 1725 will draw 18 amps according to its name plate.