# Trying to calculate from motor output to FLA(Full load amps)

• Engineering
• ovoleg
In summary: Overall, it is important to not rely on assumptions and to always seek out accurate and reliable information when solving problems.
ovoleg

## Homework Statement

Fan Motor Output: 0.172 kW
Propeller Fan

Compressor Motor Output: 2.9kW
DC Inverter-driven Scroll

Voltage: 208/230, single phase

What I need to find is the FLA for each fan motor(2), and the FLA of the compressor motor.

Total MCA = 32A

## Homework Equations

V=IR?
I'm not really sure, no other information is given.

## The Attempt at a Solution

I'm pretty sure it goes something like this but I can't find any resources that would help me calculate this. I've taken electric circuits in physics and in electrical engineering but I do not recall.

P=V*I
P=V*I*eff*PF

Going to assume the power factor = 0.8
I have no clue as to the efficiency, and I'm going to guess that its incorporated into the power factor?

For the Fan,
0.172*10^3=230*FLA*.8

FLA = 172/(230*0.8)
FLA = 0.934783 Amps.

For the compressor I'm going to make generally the same assumption, that the power factor is 0.8 and that I have no clue as to the efficiency.

FLA = 2900/(230*0.8)
FLA = 15.76087 Amps.

So since the MCA is set to 32 Amps, I'm going to at least double check,

(Compressor FLA)*1.5+(Fan FLA) = MCA
^^Pretty sure this is the equation

(15.76087)*1.5+(0.934783) = 24.57 MCA

Obviously not 32. Anyone?

it is important to always double check your calculations and assumptions. In this case, I would suggest reaching out to the manufacturer of the fan and compressor to inquire about the efficiency and power factor of their specific models. This information can greatly impact the accuracy of your calculations. Additionally, it may be helpful to consult with an electrical engineer or use online resources to better understand how to calculate FLA for different types of motors.

## 1. What is FLA?

FLA stands for Full Load Amps and refers to the maximum amount of current that a motor draws when operating at full load.

## 2. How do I calculate FLA?

To calculate FLA, you will need to know the motor's horsepower rating and voltage. Then, you can use the formula FLA = (HP x 746) / (Voltage x Efficiency x Power Factor).

## 3. What is the efficiency and power factor in the FLA formula?

Efficiency is a measure of how well a motor converts electrical energy into mechanical energy. Power factor is a measure of how efficiently the motor uses the current it draws. Both efficiency and power factor can be found in the motor's specifications.

## 4. Can I calculate FLA for any type of motor?

Yes, the FLA formula can be used for all types of motors, including single-phase and three-phase motors.

## 5. Why is it important to calculate FLA?

Calculating FLA is important for sizing electrical components, such as circuit breakers and fuses, to ensure they can handle the maximum current draw of the motor. It is also useful for troubleshooting motor performance issues and determining if the motor is operating within its design parameters.

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