Why are the windings and commutator made of copper

This could be lifting up a weight or getting it to pull against a braking system. The total efficiency of a motor is zero when there is no load it is doing no useful work. As the load increases, so the efficiency increases because it starts to do some work.

The efficiency then levels off. At this point, any extra load causes the motor to draw a bigger current. This increases both the useful work and the joule heating in the motor. They increase in proportion to each other, keeping the efficiency almost constant. These vary differently with the load. The friction and the core loss stay constant — they depend on the speed of the motor rather than the current being drawn. The joule heating losses increase with the load.

This is because the motor has to draw a bigger current to do more work. And this bigger current causes more heating in the coils. However, although the losses are increasing with load, so is the useful work being done. Animations showing the motor effect online such as this. Courtesy of PelletierPhysics. Figure 1 shows how the efficiencies of two motors depend on their load. The force on a current-carrying conductor varies with the current, the magnetic field strength and the length of the conductor.

How does force vary with:. The torque on a rotor varies with the angle of the plane of the rotor coil to the magnetic field. At what angle is the torque. Referring to Figure 2, for which two types of losses are all of the following statements true?

Go to the download section to access zip files of all resources for each subject and age group for use offline. Using Electric Motors Making motors more efficient Electric motors can be made more efficient in a number of ways. How do Electric Motors Work?

Commutator and brushes carry the d. Terminal box connects the stator coils to the 3-phase a. Picture 3. Induction motors can be made more energy efficient by: using copper windings in the stator coils using copper bars in the rotor machining all moving parts to a high precision using a special, high quality steel for the rotor and stator keeping the rotor and stator as close as possible without touching - again through precision manufacture.

Even the most efficient motors are going to lose energy in some places. This is measured by getting the motor to do work. This could be lifting up a weight or getting it to pull against a braking system.

A motor loses energy in a number of ways. Question A grounded winding would cause a breaker to trip, however, a shorted start winding would not produce enough torque to turn the compressor and the run winding would not kick in resulting in the buzzing to stop in about 5 - 10 seconds start winding timing out.

Change the compressor motor or get a new refrigerator, depending on cost factors. Call a professional for compressor replacement unless you want a huge headache. Gary Yingling - Avon Lake, Ohio. Generally rotor does not carry any winding in case of induction motor for example even if they carry in some motor, it is only excitation hence lower current, lower voltage.

Rotor can freely rotate with out any complicated brushes are commutators. Main winding actually carries load current hence better to be stationary with fixed wiring connections. Put an ohm meter on the two pins that plug into the blower motor Keep in mind that there is no motor winding that has a 0 ohm reading unless it is wound with silver or gold windings Another possibility is that you have an open resistor on the control panel itself.

The speed of that motor is controlled by various resistors inline with the motor. So if the fuses are good and the relay is not shorted, then the chances are that you have an open motor winding or a bad resistor pack in the control panel. If the motor winding does not show infinity, start looking at the control panel for a burnt resistor or a cold solder joint that is a solder joint on a circuit board that appears gray and cracked or a component that feels very loose in the circuit board.

For a couple of dollars, you can fix this yourself instead of paying some mechanic hundreds if not thousands of dollars to "impress" you with his technical know how, when in fact he was notified by the factory with a notification of the problem and exactly what causes it! Any single phase induction motor is provided by a starting technique so if it vibrates , then this means that the technique is failed.

Copper is not a weak metal even though you can bend it. Infact, polythene doesn't even conduct electricity Because copper out lasts paper, even bitumen 15 felt. Almost all electronics contain copper elements; even printed circuits. Although, yes, however, if you cook acidic food in copper dish ware, or even taste the copper salts then it is toxic! Even though gold and copper are in the same family, copper is much more reactive than gold.

This is why Copper rusts more than gold, and why there are so many copper compounds IE copper silicate Copper is higher in the family, giving it these characteristics. Gold and Copper aren't even stone, They're metal. No, and actually coins are not even made from copper at all because it is too expensive. The copper bottom is more for looks than actual purpose.

Some beleive the copper bottom provides more even heating. Gold or even Copper!! The size of the arrows represents the amount of each type of energy converted from electrical energy. The wire coils have electrical resistance; the greater the resistance, the harder it is for the current to flow and the more energy is wasted.

Compare the motors in Figure 7 and Figure The simple model motor has two poles. How many poles does the hybrid motor have? For an electric car to have zero emissions of CO 2 , the battery needs to be charged from what kind of energy?

Go to the download section to access zip files of all resources for each subject and age group for use offline. Education Resources Electric Motors.

Where are Electric Motors Used? Cars Cars have several electric motors: The starter motor turns the petrol engine to get it going Other motors work the windscreen wipers, windows and mirrors Trains An electric train has a powerful motor to drive it.

Courtesy of Otis. Figure 1: find the motor at the top of the escalator. Courtesy of Siemens. Courtesy of Tesla. Rotor coil The coil is made of copper wire, because copper is such an excellent conductor. Armature The armature supports the coil and can help make the electromagnet stronger. Permanent magnets There are two permanent magnets. Commutator Each end of the coil is connected to one of the two halves of the commutator.

Brushes The brushes press on the commutator. S teel former The former made of magnetic material links the two permanent magnets and, in effect, makes them into a single horseshoe shaped magnet. Why Does it Turn? Courtesy of PelletierPhysics. Courtesy of AVL. Figure An electric motor and batteries replacing a petrol engine in a Porsche car. Energy Transfers Sankey Diagram We supply electrical energy to an electric motor.