# How are electric motors rated?

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Power is in general rated in watt (W) or horsepower (hp). The old imperial unit horsepower is equal to 746 watts (0.745 kW) or 33000 lb ft per minute (or 550 lb ft per second).

## How is electric motor rating determined?

Multiply the motor voltage by the full-load current. The result is in watts. Divide watts by 1,000 to give kilowatts. For example, 230 volts x 20 amps = 4,600 watts; 4,600 watts divided by 1000 = 4.6 kilowatts.

## What is rating of an electric motor?

Power rating for electrical machines indicates the required supply voltage for smooth running of that machine, it also shows the permissible maximum amount of current which can easily flows through the machine and there will be a chance of breakdown in the machine if those parameters goes beyond this limit.

## What do the numbers on an electric motor mean?

Generally, the first two numbers indicate the diameter of the entire can of the motor OR the diameter of the stator (the inner part of the motor) only. … Similarly, the second pair of numbers can indicate either the height of the entire motor, or only the height of the stator.

## What does the amp rating on a motor mean?

A tools amp rating indicates the electrical current load a motor can carry for an indefinite period of time without degrading the insulation and other electrical compounds of the motor. … Amps basically measure how effectively the motor cools itself, not how much power it has.

## On what ratings the selection of motors depends?

Explanation: The current rating of the Induction motor depends upon the cross-section area of the conductors. Resistance ∝ 1÷Area, I ∝Area. 3.

## Is rated current same as full load current?

Full load and rated current are one and the same. It is that value of current for which an electrical equipment can function continuously without any issues.

## Why is electric motor rated in kW?

Motor is rated in kW since it specifies the capacity of the motor to drive its load. It is the active power (kW) that is of interest when a motor drives a load. The motor converts the active power that it draws from the mains into mechanical power that the load consumes/demands. … Thus, a motor is rated in terms of kW.

## How is motor current rating calculated?

The motor FLA calculator uses the following formulas:

1. Single Phase AC Motor FLA (Amperes) = (P [kW] × 1000) / (V × cos ϕ)
2. Single Phase AC Motor FLA (Amperes) = (P [HP] × 746) / (V × cos ϕ × η)
3. Three Phase AC Motor FLA (Amperes) = (P [kW] × 1000) / (V × 1.732 × cos ϕ)

## What is rated speed of motor?

The rated speed is the speed at which the motor will first produce its maximum designed power output, and “maximum speed,” the fastest the motor can spin while producing that same amount of power./:m] ]The reduction ratio should be applied on the RPM while your load is attached to the motor.

## Why motors are rated in HP?

That’s why we are rated Motor in kW or HP (kilowatts/ Horsepower) instead of kVA. in more clear words, Motor only consumes active power and provides mechanical power in HP or kW at motor shaft. In addition, Motor is a device which converts Electrical power into Mechanical power.

## How do you read a motor rating plate?

The RPM listed on the nameplate is the shaft speed for the motor. The speed of the motor is directly related to the frequency of the line voltage and the number of poles in the motor. At 60 Hz, a 4 pole motor will rotate at approximately 1800 RPM (7200/4 poles).

## What is rated voltage of a motor?

RATED voltage is the voltage on the nameplate – the “design point” for maximum power throughput and safe thermal operation. OPERATING voltage is the actual voltage applied at the terminals to the electrical equipment. For example – a machine has a rated voltage of 4160 volts at 60 Hz.

## Is it better to have more amps or volts?

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A higher voltage system is more efficient than a lower voltage since it experiences less energy loss from resistance given the same amount of power draw. … You get the same exact voltage—but with 80 amps of current. That’s 80% more energy!

## What happens if the amps are too high?

A higher voltage than a device is designed for will most likely blow up some components, but amperage is derived from how much current is actually drawn, based on the device’s resistance, so having “too much” is not a problem and will do no harm.

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## Are volts or amps more important?

As important as amps and volts are when considering on which you should place more emphasis, is the use. … If it’s hanging curtain rods, low amp and low voltage should serve you well. If it’s for big indoor and outdoor projects, higher voltage and lower amperage could be the best bet.