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Question:

What determines the speed of a electric motor. Volt or Amp?

got an idea that i want to play with involving a small electrical motor. I want to know if i must increase the voltage or ampere to increase the speed since it doesnt have controls for that

Answer:

From my experimental research, with a DC motor, I found that the higher the voltage meant that it turned faster and the higher the current, the harder it was to hold the motor still, so current affects torque and voltage affects revs. I had no apparatus to measure the revs or torque, I am just judging by how fast the fan seemed to turn and how difficult it was to stop with my hands, but I did have a multi meter to measure the voltage and amperage.
The speed of a motor is determined by how the Stator and Amateur or wound.
Best to think of it as Volts give you more speed, Amps give you more Torque. Think about how much torque it'll take just to overcome the friction of the rotor.
volt
An AC motor running with 60 Hz will rotate at 60 RPS or 3600 RPM, but this is for a motor with a single pair of poles. The formula is 3600/#-pair-poles. Many have two poles so they will rotate at 1800 RPM. That is for Synchronous motors. Big motors like the ones on AC units are Asynchronous, here there is a displacement so an 1800 RPM motor will run at ~1750 RPM. Now, if you are referring to DC motors, there are two types, series and parallel. The RPM on a series one will depend on the voltage applied and the load. I have to admit that I don't remember what happens on a parallel one, may be I never learned it right. When you apply a Voltage and the motor is under load, it will draw so many Amps. So, Amps is a consequence of the electric power needed to overcome the mechanical power. Most DC motors have commutators and brushes, the RPM also depends on how many contacts on the commutator. The reason for the commutator is to reverse the magnetic field every fraction of a revolution, such that the motor will rotate. The so called brush-less DC motors don't have commutators, they are equipped with transistor-switching that do the job of commutation.

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