Frequent question: Can an electric motor be a resistor?

Does a motor act like a resistor?

The motor is itself a resistor. Look at all that wire inside it. This limits the current it takes when stalled. Not a lot; but a motor that takes 1 Amp when running may take 10-15 Amps when stalled, due to that resistance alone.

Do electric motors have resistance?

When testing electric motors, it is useful to know the insulation resistance between motor winding(s) and the frame ground. This value will normally be in the range of tens to millions of ohms.

Why do motors have resistors?

Motor Starting Resistors are used to reduce the voltage at the motor terminals and also decrease the starting current. … Because there will be no back electromotive force (emf) to limit this current, some series resistance can be added to the armature windings.

Why does a DC motor need a resistor?

These resistors are used to control the torque and speed of AC and DC motors, along with limiting in-rush current. … By changing the level of resistance in the circuit (the Motor Control Resistor), speed and torque can be adjusted. In other words, higher resistance means reduced torque and speed.

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Is back emf AC or DC?

Back EMF can have either a sinusoidal (AC) or a trapezoidal (DC) waveform. The shape of the back EMF is important, as it determines the type of drive current and commutation method that should be used for the motor.

What happens when primary resistors are used to start a motor?

Primary resistor starters provide closed transition starting. This means the motor is never disconnected from the line from the moment it’s first connected until the motor is operating at full line voltage. This feature may be important in wiring systems sensitive to voltage changes.

Should an electric motor have continuity?

The windings (all three in a three-phase motor) should read low but not zero ohms. … It will usually be low enough (under 30 Ω) for the audible continuity indicator to sound. For proper motor operation, all windings must have megohm readings to ground, i.e. to the motor enclosure.

How do you calculate the resistance of a motor?

Ohm’s law tells you that current through a wire – even a long wire wound around a motor solenoid – is equal to the voltage divided by the resistance. You can determine the resistance of a motor coil if you know the wire gauge, the radius of the solenoid and the number of windings.

How do gears slow down a motor?

If you want to slow down gradually, take your foot off the accelerator and switch to a lower gear, such as second or third (remembering to rev-match as you downshift). This will slow the car down without you having to touch the brakes.

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How do you slow down a 12v motor?

If you want to reduce rpm without compromising speed regulation then use a voltage regulator or PWM controller to lower the motor voltage. If you also want higher torque then use a gearbox (which increases torque by the same proportion as it reduces shaft rpm).

How do you make an electric motor spin slower?

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.