# Can DC motors spin freely?

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No, with any direct-drive motor there is significant drag force required to turn the hub due to the strong interaction between the magnets and the stator.

## Can DC motors spin both ways?

Simply put, DC motors can turn in either direction (clockwise or counter-clockwise) and can be easily controlled by inverting the polarity of the applied voltage. … If a motor is already in motion, the applied voltage can be inverted and the motor will decelerate quickly, eventually stopping.

## Do brushless motors spin freely?

A brushless motor should spin freely when all the wires are separated as there is not a complete circuit. If the motor resists your rotation regardless of the wire connections, it’s likely that your motor has an internal short circuit.

## How does a DC motor rotate?

The rotation of the DC motor is accomplished by the force which is developed on a current-carrying conductor in a magnetic field. The current-carrying conductor is connected to the shaft which is able to rotate relative to the stationary body of the DC motor.

## How long can a DC motor run continuously?

You should anticipate, given proper attendance, that the motor can run continuously for the life of its brushes, which should be in the range of six months to a year. Presuming that the motor is too small to have its brushes changed by a trained electrician while running.

## What is back emf in dc motor?

When the armature of the DC motor rotates under the influence of driving torque, the armature of the conductors moves through a magnetic field inducing an emf in them. The induced emf is in the opposite direction to the applied voltage and is known as the back emf.

## Should a motor turn freely?

The starter can spin freely when it’s not attached to the engine, but when it’s connected, it shouldn’t spin without turning the motor. When connected, the starter motor is designed to turn the engine when it spins.

## How freely should an electric motor spin?

Turn the motor shaft by hand. … There will always be a little drag, but the shaft should spin relatively freely. Still, an older motor may have bearings with dried grease. If the bearings are not rusted inside, you can probably work new grease into them.

## Which is not rotating part of a DC motor?

A DC motor consists of two parts, a “Stator” which is the stationary part and a “Rotor” which is the rotating part.

## Can I connect DC motor directly to battery?

You also can’t connect a DC generator directly to the battery either … … That sounds like a brushless DC motor or BLDC motor. It is really a 3 phase motor meant to run from a variable frequency 3 phase electronic drive.

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## What is field current in dc motor?

: the current supplied to the field windings of a generator or motor to establish the magnetic field for its operation.

## What causes a DC motor to fail?

The most common cause of motor failure, and arguably the most difficult to overcome, is low resistance. Low resistance is caused by the degradation of the insulation of the windings due to conditions such as overheating, corrosion, or physical damage.

## What is field weakening in DC motor?

Field weakening is a method of raising the speed in DC motors. If the field (magnetic field) is weakened by reducing field current, back emf is reduced and thereby more armature current is drawn. Now torque is produced due to interaction of armature current and field flux.

## Which battery is best for DC motor?

7.2V: six AA or AAA rechargeable NiMh batteries is perfect for 7.2V DC gear motors. These are usually in a battery pack rather than as individual cells and you will need a more specific NiMh battery pack charger. 7.4V: two LiPo cells can often power a microcontroller and works great for 7.2V DC gear motors.