# What determines the RPM of an electric motor?

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The rotating speed of an electric motor depends on two factors: its physical construction, and the frequency (Hz) of the voltage supply. Electrical engineers select the speed of a motor based on the needs of each application, similar to how the mechanical load determines the horsepower required.

## How do electric motors increase rpm?

By increasing the voltage of the armature, it produces more magnetic forces to overcome the field magnet, increasing the rpm. By increasing the field current, more magnetic fields opposing the motion are produced, at the same time more cemf is produced reducing the armature voltage, decreasing the rpm.

## Do electric motors have rpm?

Therefore, to get the same power you’d then need to run the motor at higher revolutions per minute. Today’s electric cars run at around 12,000 rpm; motors for up to 20,000 rpm are being prepared for the next generation; and machines reaching 30,000 rpm are under investigation.

## What is the maximum rpm of an electric motor?

In this case, unless external limitations are applied, the maximum torque is achieved at low RPM. For example, the AC motor found in the Tesla Roadster (2008) produces near constant maximum torque from 0 to about 6000 RPM, while maximum power occurs at about 10000 RPM, long after torque begins to drop off.

## Can you change rpm on electric motor?

AC motors are constant speed devices but their speed can vary if you change the input voltage or frequency or the windings that make the motor rotate. The most common and efficient way of changing the speed is to vary the frequency by using an inverter as the power supply.

## How do I lower the RPM on my electric motor?

A couple of things you can do:

1. Use gears to change ratio of speed, which is what you’re going to do. …
2. Use a stepper motor, which are commonly used for high-torque, low RPM applications.
3. Find some sort of PWM control circuit to slow it down, although you probably won’t be able to get it down to 5-10RPM.

## How do you speed up an electric motor?

To speed up an induction motor, you could 1) reduce the load on it (may increase speed 2 or 3%. 2) increase the frequency of the supply power 3) re-wind the stator to have fewer pole pairs. Voltage affects the torque and the frequency decides the motor speed (for a given no. of poles of the motor).

## Do electric motors slow with age?

Generally electric motors don’t slow their speed during years or decades. You have only to check bearings, and brushes, only for brushed motors. Most electric motors, whether AC or DC, fail after time for reasons that may not be electrical in nature.

## How do you determine if a motor is AC or DC?

Look for the stator core construction and rotor. If there is no commutator, then it is a AC motor. If there is a commutator and brushes, it may be either a DC motor or an AC commutator motor (Universal motor).

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