- Отрасли: Electrical equipment
- Number of terms: 4774
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Unless otherwise specified, a general-purpose DC motor is reversible. A DC motor can be reversed by changing the polarity of the field or the armature, but not both. When rapid reversing is necessary, the armature circuit is reversed. In some cases, it is frequently more advantageous to reverse the field connections of shunt motors, since the controls have to handle much less current, especially on large motors, than do armature-circuit contactors. An AC motor is reversed by reversing the connections of one leg on three-phase power or by reversing the leads on single phase.
Industry:Electrical equipment
The rotating member of an induction motor made up of stacked laminations. A shaft running through the center and a squirrel cage made in most cases of aluminum which holds the laminations together and act as a conductor for the induced magnetic field. The squirrel cage is made by casting molten aluminum into the slots cut into each lamination.
Industry:Electrical equipment
A defect in a winding which causes part of the normal electrical circuit to be bypassed. This frequently results in reducing the resistance or impedance to such an extent as to cause overheating of the winding, and subsequent burnout.
Industry:Electrical equipment
The speed of the motor refers to the RPM's (revolutions per minute) of the shaft.
Industry:Electrical equipment
Amount of current drawn at the instant a motor is energized - in most cases much higher than that required for running. Same as locked rotor current.
Industry:Electrical equipment
The torque or twisting force delivered by a motor at the instant it is energized. Starting torque is often higher than rated running or full load torque.
Industry:Electrical equipment
That part of an AC induction motor's magnetic structure which does not rotate. It usually contains the primary winding. The stator is made up of laminations with a large hole in the center in which the rotor can turn; there are slots in the stator in which the windings for the coils are inserted.
Industry:Electrical equipment
A motor which operates at a constant speed up to full load. The rotor speed is equal to the speed of the rotating magnetic field of the stator; there is no slip. There are two (2) major types reluctance and permanent magnet on synchronous motors. A synchronous motor is often used where the exact speed of a motor must be maintained.
Industry:Electrical equipment
The speed of the rotating magnetic field set up by the stator winding of an induction motor. In a synchronous motor the rotor locks into step with the rotating magnetic field, and the motor is said to run at synchronous speed. Approximately the speed of the motor with no load on it.
Industry:Electrical equipment
A small generator normally used as a rotational speed sensing device. Tachometers are typically attached to the output shaft of DC or AC inverter motors requiring close speed regulation. The tachometer feeds its signal to a control which adjusts its output to the DC motor or AC inverter motors accordingly (called "closed loop feedback" control).
Industry:Electrical equipment
