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Neodymium Magnets are used the Motor [2013-10-14]

 

That article describes how to levitate the motor's spinning shaft using neodymium magnets.
 
 
The motor consists of a spinning shaft that is held up by repelling magnets, stabilized by resting a point against a wall.  It is powered by solar panels mounted on the spinning shaft, which generate currents through coils of insulated wire.
 
How does an electric motor work?
Like many electric motors, the Mendocino motor consists primarily of two magnets.
 
One magnet is a permanent magnet that provides a steady magnetic field.  In fact, that’s why they’re called "permanent magnets", because the field stays on all the time.
The second magnet is a coil of wire that acts as an electromagnet that we can switch on and off.  When a current is running through this coil of wire, it acts like another magnet, complete with a north and south pole.
 
Magnetic Forces in an electic motor
Let's forget about the electromagnet for a moment.  Just imagine setting two permanent magnets near each other.  One will remain stationary, while the other is free to rotate on a shaft, right next to the first.  Magnetic forces will tend to try to rotate the freely spinning magnet to align its magnetic field with the stationary magnet’s field.
 
 
What is the torque on this rotating magnet at various positions?  How strong are the magnetic forces trying to rotate it?  In the graphic showing various rotational positions below, we can see where the torque is highest, and in what direction.  The torque shown represents the torque acting on the rotating magnet in that position.
 
 
Let's get back to that coil of wire idea, an electromagnet we can switch on and off electronically.  If we replace one of these magnets (let’s pick the spinning one) with an electromagnet, we can switch the electric current on and off at various portions of the rotation cycle.  We should be able to turn on the electricity to try and spin it in one direction, spinning the motor shaft.
 
When should we turn the electric current on?  In which direction?
 
In the graphic below, we change the rotating magnet into an electromagnet, represented by the classic example of wire wound around a nail.  In one region, from 45 to 135 degrees of rotation, we run current through the electromagnet in one direction.  To keep trying to rotate the spinning electromagnet in the same clockwise direction, we run current in the opposite direction in the 225 to 315 degree region.
 
Because we run the current in opposite directions, the torque is always turning the shaft in one direction.  During the "off" periods, inertia of the spinning motor has to be enough to get it to the next "on" cycle for it to keep spinning.
 
 
In brushed DC motors, conductive brushes are set up to make contact from an electrical source to the coil of wire.  With brushes setup to only make contact during those times in the rotation cycle that will help it rotate, the motor will spin powered by the electric current provided.
 
Modern brushless DC motors work using similar on/off cycles, but use other means to figure out where in the cycle the spinning motor is.  From Wikipedia:
 
Because the controller must direct the rotor rotation, the controller requires some means of determining the rotor's orientation/position (relative to the stator coils.) Some designs use Hall effect sensors or a rotary encoder to directly measure the rotor's position. Others measure the back EMF in the undriven coils to infer the rotor position, eliminating the need for separate Hall effect sensors, and therefore are often called sensorless controllers.That article describes how to levitate the motor's spinning shaft using neodymium magnets.
 
 
The motor consists of a spinning shaft that is held up by repelling magnets, stabilized by resting a point against a wall.  It is powered by solar panels mounted on the spinning shaft, which generate currents through coils of insulated wire.
 
How does an electric motor work?
Like many electric motors, the Mendocino motor consists primarily of two magnets.
 
One magnet is a permanent magnet that provides a steady magnetic field.  In fact, that’s why they’re called "permanent magnets", because the field stays on all the time.
The second magnet is a coil of wire that acts as an electromagnet that we can switch on and off.  When a current is running through this coil of wire, it acts like another magnet, complete with a north and south pole.
 
Magnetic Forces in an electic motor
Let's forget about the electromagnet for a moment.  Just imagine setting two permanent magnets near each other.  One will remain stationary, while the other is free to rotate on a shaft, right next to the first.  Magnetic forces will tend to try to rotate the freely spinning magnet to align its magnetic field with the stationary magnet’s field.
 
 
What is the torque on this rotating magnet at various positions?  How strong are the magnetic forces trying to rotate it?  In the graphic showing various rotational positions below, we can see where the torque is highest, and in what direction.  The torque shown represents the torque acting on the rotating magnet in that position.
 
 
Let's get back to that coil of wire idea, an electromagnet we can switch on and off electronically.  If we replace one of these magnets (let’s pick the spinning one) with an electromagnet, we can switch the electric current on and off at various portions of the rotation cycle.  We should be able to turn on the electricity to try and spin it in one direction, spinning the motor shaft.
 
When should we turn the electric current on?  In which direction?
 
In the graphic below, we change the rotating magnet into an electromagnet, represented by the classic example of wire wound around a nail.  In one region, from 45 to 135 degrees of rotation, we run current through the electromagnet in one direction.  To keep trying to rotate the spinning electromagnet in the same clockwise direction, we run current in the opposite direction in the 225 to 315 degree region.
 
Because we run the current in opposite directions, the torque is always turning the shaft in one direction.  During the "off" periods, inertia of the spinning motor has to be enough to get it to the next "on" cycle for it to keep spinning.
 
 
In brushed DC motors, conductive brushes are set up to make contact from an electrical source to the coil of wire.  With brushes setup to only make contact during those times in the rotation cycle that will help it rotate, the motor will spin powered by the electric current provided.
 
Modern brushless DC motors work using similar on/off cycles, but use other means to figure out where in the cycle the spinning motor is.  From Wikipedia:
 
Because the controller must direct the rotor rotation, the controller requires some means of determining the rotor's orientation/position (relative to the stator coils.) Some designs use Hall effect sensors or a rotary encoder to directly measure the rotor's position. Others measure the back EMF in the undriven coils to infer the rotor position, eliminating the need for separate Hall effect sensors, and therefore are often called sensorless controllers.That article describes how to levitate the motor's spinning shaft using neodymium magnets.
 
 
The motor consists of a spinning shaft that is held up by repelling magnets, stabilized by resting a point against a wall.  It is powered by solar panels mounted on the spinning shaft, which generate currents through coils of insulated wire.
 
How does an electric motor work?
Like many electric motors, the Mendocino motor consists primarily of two magnets.
 
One magnet is a permanent magnet that provides a steady magnetic field.  In fact, that’s why they’re called "permanent magnets", because the field stays on all the time.
The second magnet is a coil of wire that acts as an electromagnet that we can switch on and off.  When a current is running through this coil of wire, it acts like another magnet, complete with a north and south pole.
 
Magnetic Forces in an electic motor
Let's forget about the electromagnet for a moment.  Just imagine setting two permanent magnets near each other.  One will remain stationary, while the other is free to rotate on a shaft, right next to the first.  Magnetic forces will tend to try to rotate the freely spinning magnet to align its magnetic field with the stationary magnet’s field.
 
 
What is the torque on this rotating magnet at various positions?  How strong are the magnetic forces trying to rotate it?  In the graphic showing various rotational positions below, we can see where the torque is highest, and in what direction.  The torque shown represents the torque acting on the rotating magnet in that position.
 
 
Let's get back to that coil of wire idea, an electromagnet we can switch on and off electronically.  If we replace one of these magnets (let’s pick the spinning one) with an electromagnet, we can switch the electric current on and off at various portions of the rotation cycle.  We should be able to turn on the electricity to try and spin it in one direction, spinning the motor shaft.
 
When should we turn the electric current on?  In which direction?
 
In the graphic below, we change the rotating magnet into an electromagnet, represented by the classic example of wire wound around a nail.  In one region, from 45 to 135 degrees of rotation, we run current through the electromagnet in one direction.  To keep trying to rotate the spinning electromagnet in the same clockwise direction, we run current in the opposite direction in the 225 to 315 degree region.
 
Because we run the current in opposite directions, the torque is always turning the shaft in one direction.  During the "off" periods, inertia of the spinning motor has to be enough to get it to the next "on" cycle for it to keep spinning.
 
 
In brushed DC motors, conductive brushes are set up to make contact from an electrical source to the coil of wire.  With brushes setup to only make contact during those times in the rotation cycle that will help it rotate, the motor will spin powered by the electric current provided.
 
Modern brushless DC motors work using similar on/off cycles, but use other means to figure out where in the cycle the spinning motor is.  From Wikipedia:
 
Because the controller must direct the rotor rotation, the controller requires some means of determining the rotor's orientation/position (relative to the stator coils.) Some designs use Hall effect sensors or a rotary encoder to directly measure the rotor's position. Others measure the back EMF in the undriven coils to infer the rotor position, eliminating the need for separate Hall effect sensors, and therefore are often called sensorless controllers.That article describes how to levitate the motor's spinning shaft using neodymium magnets.
 
 
The motor consists of a spinning shaft that is held up by repelling magnets, stabilized by resting a point against a wall.  It is powered by solar panels mounted on the spinning shaft, which generate currents through coils of insulated wire.
 
How does an electric motor work?
Like many electric motors, the Mendocino motor consists primarily of two magnets.
 
One magnet is a permanent magnet that provides a steady magnetic field.  In fact, that’s why they’re called "permanent magnets", because the field stays on all the time.
The second magnet is a coil of wire that acts as an electromagnet that we can switch on and off.  When a current is running through this coil of wire, it acts like another magnet, complete with a north and south pole.
 
Magnetic Forces in an electic motor
Let's forget about the electromagnet for a moment.  Just imagine setting two permanent magnets near each other.  One will remain stationary, while the other is free to rotate on a shaft, right next to the first.  Magnetic forces will tend to try to rotate the freely spinning magnet to align its magnetic field with the stationary magnet’s field.
 
 
What is the torque on this rotating magnet at various positions?  How strong are the magnetic forces trying to rotate it?  In the graphic showing various rotational positions below, we can see where the torque is highest, and in what direction.  The torque shown represents the torque acting on the rotating magnet in that position.
 
 
Let's get back to that coil of wire idea, an electromagnet we can switch on and off electronically.  If we replace one of these magnets (let’s pick the spinning one) with an electromagnet, we can switch the electric current on and off at various portions of the rotation cycle.  We should be able to turn on the electricity to try and spin it in one direction, spinning the motor shaft.
 
When should we turn the electric current on?  In which direction?
 
In the graphic below, we change the rotating magnet into an electromagnet, represented by the classic example of wire wound around a nail.  In one region, from 45 to 135 degrees of rotation, we run current through the electromagnet in one direction.  To keep trying to rotate the spinning electromagnet in the same clockwise direction, we run current in the opposite direction in the 225 to 315 degree region.
 
Because we run the current in opposite directions, the torque is always turning the shaft in one direction.  During the "off" periods, inertia of the spinning motor has to be enough to get it to the next "on" cycle for it to keep spinning.
 
 
In brushed DC motors, conductive brushes are set up to make contact from an electrical source to the coil of wire.  With brushes setup to only make contact during those times in the rotation cycle that will help it rotate, the motor will spin powered by the electric current provided.
 
Modern brushless DC motors work using similar on/off cycles, but use other means to figure out where in the cycle the spinning motor is. From Wikipedia:
 
Because the controller must direct the rotor rotation, the controller requires some means of determining the rotor's orientation/position (relative to the stator coils.) Some designs use Hall effect sensors or a rotary encoder to directly measure the rotor's position. Others measure the back EMF in the undriven coils to infer the rotor position, eliminating the need for separate Hall effect sensors, and therefore are often called sensorless controllers.

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