What will the direction of the force on the wire be?
The magnetic field exerts a force on a current-carrying wire in a direction given by the right hand rule 1 (the same direction as that on the individual moving charges). This force can easily be large enough to move the wire, since typical currents consist of very large numbers of moving charges.
What is meant by Fleming’s left-hand rule?
Fleming’s left-hand rule states that: When a current-carrying conductor is placed in an external magnetic field, the conductor experiences a force perpendicular to both the field and to the direction of the current flow. It was invented by John Ambrose Fleming.
Which hand is used to predict the direction of the force from the motor effect?
The direction of a motor effect force can be found using Fleming’s left-hand rule.
What affects the size and direction of the force on a wire?
If the current-carrying wire is placed in a magnetic field (whose lines of force are at right angles to the wire) then it will experience a force at right angles to both the current direction and the magnetic field lines. The force increases if the strength of the magnetic field and/or current increases.
How do you reverse the direction of motor?
In order to reverse the direction of an AC motor, the magnetic fields must be altered to provoke movement in the opposite direction. Since each wire consists of a positive and negative current within the magnetic fields, the flip-flopping of main and starter wires causes the motor to run in reverse rotation.
What can you do to a motor to make it spin faster?
One easy way to make the motor run faster is to add another magnet. Hold a magnet over the top of the motor while it is running. As you move the magnet closer to the spinning coil, one of two things will happen. Either the motor will stop, or it will run faster.
What electric motor has the best efficiency?
Tests carried out on a 44 megawatt 6-pole synchronous ABB motor shortly before delivery showed an efficiency 0.25 percent greater than the 98.8 percent stipulated in the contract, resulting in the world record for electric motor efficiency.
Why are electric motors never 100% efficient?
While there is less friction, there are still friction losses within a motor, and the faster the rotor spins, the more wind loss it will have thanks to air resistance. Electric motors have an efficiency of less than 100% because there is ALWAYS energy loss through any mechanism imaginable.
Which is more efficient DC or AC motor?
AC induction motors use a series of coils powered and controlled by AC input voltage. Consequently, AC motors are less efficient than DC motors. In fact, the DC motor is 30% more efficient than AC motors due to the secondary magnetic field being generated from the permanent magnets rather than copper windings.
Why is AC motor preferred over DC?
AC motors are generally considered to be more powerful than DC motors because they can generate higher torque by using a more powerful current. However, DC motors are typically more efficient and make better use of their input energy.
How do you know if a motor is AC or DC?
Look for the commutator & brushes and salient field system to confirm. (iii) has 5 terminals, then it is a AC synchronous motor (3 for stator and 2 for field). Look for 2 slip rings for rotor dc supply. (iii) has 4 terminals, then it may be a DC motor, in which case look for the commutator & brushes to confirm.