# How do you calculate the power of an AC motor?

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A watt (W) is a unit of power defined as one Joule per second. For a DC source the calculation is simply the voltage times the current: W = V x A. However, determining the power in watts for an AC source must include the power factor (PF), so W = V x A x PF for AC systems.

## What is the formula of AC motor?

Electric Motor Formula

TO FIND DIRECT CURRENT THREE PHASE
CURRENT P V x EFF P 1.732 x V x EFF x PF
EFFICIENCY 746 x HP V x I 746 x HP 1.732 x V x I x PF
POWER FACTOR —— Input Watts 1.732 x V x I
SHAFT SPEED —— 120 x F no. of poles

## How is electric motor HP calculated?

The quickest method to closely estimate motor horsepower is to use a digital clamp meter to measure current and voltage to the motor, and then perform a simple calculation. Use this formula to estimate motor horsepower. Horsepower(hp)= Voltage x Amperage x % EFF x power factor x 1.73/746.

## How can you tell how powerful an electric motor is?

When talking about an electrical system such as that found in an electric vehicle, the mechanical power — given in watts (W), kilowatts (kW) or horsepower (PS) — is calculated by multiplying speed (RPM) by torque, the rotational equivalent of linear force, measured in pound-feet (lb-ft) or Newton meters (Nm).

## How do you calculate power in a 3 phase motor?

Calculate three-phase motor power consumption by multiplying amps by volts by the square root of three (W = AV(sqrt 3). For example, if the motor is drawing 30 amps at 250 volts, you have 30 x 250 x sqrt 3 (about 1.73) = 12,975 watts).

## What is the efficiency formula?

Efficiency is often measured as the ratio of useful output to total input, which can be expressed with the mathematical formula r=P/C, where P is the amount of useful output (“product”) produced per the amount C (“cost”) of resources consumed.

## How many HP is RPM?

In other words, power is the rate of completing work (or applying torque) in a given amount of time. Mathematically, horsepower equals torque multiplied by rpm. H = T x rpm/5252, where H is horsepower, T is pound-feet, rpm is how fast the engine is spinning, and 5252 is a constant that makes the units jibe.

## Do electric motors have horsepower?

Electric Motors

An electric motor’s output is measured in kilowatts. Companies that build electric cars continue to talk about horsepower because consumers are still more familiar with that type of unit. The equation is as simple as hp = kW x 1.369, so a 100-kW motor produces 136 horsepower.

## How power of a motor is calculated?

By taking the voltage and multiplying it by the associated current, the power can be determined. A watt (W) is a unit of power defined as one Joule per second. For a DC source the calculation is simply the voltage times the current: W = V x A.

## What size electric motor do I need?

General rule of thumb: you need at least 2 lbs. of thrust for every 100 lbs. of fully-loaded boat weight (people and gear included). If things like wind or current are major factors where you fish, you’ll want a little extra thrust.

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## How does a simple electric motor work?

This simple electric motor works by the magnetic force F = IL x B. The current goes around the coil so that it points one direction in one end of the loop and in the other direction at the other end of the loop. The magnetic field at both of these spots points in the same direction.

## How much power does a 3 HP motor use?

If the motor is fully loaded, it will provide output power of 3HP = (3 X 0.746) kW = 2.24 kW. Electrical input power = output power / (Efficiency /100). Unit consumed = Power in kW X numbers of hours of operation. = 59.76 units.

## How many volts is a 3 phase line?

3 phase system is expressed with line voltages. The line votage is 440 volt. Also the voltage between any one phase and neutral for a 3 phase system is 240 volts.

## What is the formula for KVA 3 phase?

Electrical Formulae for Calculating Amps, Horsepower, Kilowatts, & KVA

To Find… Direct Current Alternating Current
Three Phase
Amperes when Kilowatts are known KW x 1000 E KW x 1000 E x PF x 1.73
Amperes when “KVA” is known KVA x 1000 E x 1.73
Kilowatts E x I 1000 E x I x 1.73 x PF 1000