Part 3 -Electric Motor We will be using a \"Saint Louis\" style of motor. It con
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Question
Part 3 -Electric Motor We will be using a "Saint Louis" style of motor. It consists of a wire-wrapped iron core on an axis spindle. The wire ends are connected to a split-ring commutator. The split ring rotates between two fixed contacts as shown below: Current from the battery passes through the upper fixed contact into the "black" half of the split-ring. From there they go into the coil, turning the coil into an electromagnet with, say, the square end of the coil (where current enters) behaving as a north magnetic pole and the round end (where current leaves) behaving like a south magnetic pole. Half a rotation later the situation is as shown below: his electromagnet is then placed in a magnetic field from two permanent magnets. The magnetic field from the electromagnet is trying to align with the magnetic field from the permanent magnets so the coil will rotate. The split ring commutator will continually change the direction of the magnetic field in the electromagnet so it will continue to rotate. Conceptual practice: 1. In the second diagram above, label the direction of the current on each of the wires connected to the coil. Also, label the North and South Poles that are created on the coil. 2. In the diagram on the next page, the coil is shown at four different points in its rotation. For each of the four cases, label the direction of the current on each of the wires connected to the coil. Also, label the North and South Poles that are created on the coil. 3. Explain how you know if the coil on the next page is rotating clockwise or counterclock wise. it goes cou nerclocerise because-me North sidef magner will, repel tExplanation / Answer
1. The motor turns due to the rotation of electromagnet about a fixed axis. This electromagnet is like an iron rod with wire wrapped around. When we pass current through this wire, the iron rod becomes magnet. This magnet will have north and south poles and will try to align themselves with fixed magnet's poles. In doing so, they set up a rotational motion which is transferred to electric motor.
2. The polarity of electromagnet depends on the direction of current. Switching the current direction will switch the location of poles and this will lead to continous rotation of electromagentic due to repulsive and attractive forces.
3. When like pole comes closer to unlike pole due to attraction, we change the magnetic poles location (polarity). Now the previous north will become south and south will become north. Please note that this switching of poles usually takes place in electromagnet(rotating) not the fixed magnets. After switching, the electromagnet ends up near like pole again which causes it to reverese its rotation and this process goes on.
Alternating currents are best suited for this as they are reversible in nature.