When a bad motor winding cannot be found by a physical inspection, many times an ohmmeter may show that there is a defective winding. Most repair shops will use a "megger" or a ground insulation tester. The megger will help to detect areas of deteriorating insulation where the windings may soon short.
In 1820, Hans Christian Oersted conducted an important experiment with electrical equipment, in which he discovered that electric currents generate magnetic fields. Magnets can either attract or repel each other through their magnetic fields. This phenomenon allows a wire to be either pushed or pulled by a magnet. Soon after Oersted's discovery, Michael Faraday discovered that changing magnetic fields could create electric currents in nearby wires. These two effects were found to be concentrated if the wire is wound up into coils. These windings of wire became the basis for induction motors.
Function of Motor Stator Winding
Windings appear elsewhere in induction motors as well. An induction motor uses electromagnets instead of permanent magnets. Electromagnets are made out of windings of wire. These windings are called stator windings, because unlike the rotor windings, they are stationary. Current runs through the stator windings to generate the magnetic field that turns the armature.
Role of Iron
Both the rotor and the stator windings are placed on cores made of iron. Iron is a very easily magnetized material. When a Stator Winding;s current starts up, the magnetic field it generates magnetizes the iron that the Stator Coil Winding is wrapped around. Iron retains its magnetization very well, so the iron cores concentrate and multiply the magnetic fields that the windings generate. This makes the motion they produce more powerful.
Considerations
Magnetic Motor Parts windings have some fundamental differences. Stator windings are multiple coils hooked up to each other in series. This means that the wire at the end of one, is connected directly to the wire at the beginning of the next. Each stator winding is wound in the opposite direction from those on either side. This allows it to present alternating magnetic poles, a crucial feature of induction motor design. They also connect directly to a power source. Rotor windings, on the other hand, are short-circuited. They do not connect to an external power supply or any other coils. Their electricity is entirely supplied by induction from the stator coils.