- Industry: Electrical equipment
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The moment of inertia is expressed as Wk2or WR2in terms of pound-feet squared. It is the product of the weight of the object in pounds and the square of the radius of gyration in feet.
If the application is such that the motor is driving through a pulley or gear so that the driven equipment is operating at a higher or lower speed than the motor, it is necessary to calculate the inertia "reflected to the motor shaft," that is, an equivalent Wk2(reflected to motor shaft) = Wk2 based on the rpm of the motor.
Industry:Electrical equipment
The amount of power required to maintain a current of one ampere at a pressure of one volt. Most motors are rated in Kwatt equal to 1,000 watts. One horsepower is equal to 746 watts.
Industry:Electrical equipment
A DC motor which changes speed only slightly from a no load to a full load condition. In AC motors, these are synchronous motors.
Industry:Electrical equipment
The time rate of flow of electrical charge and is measured in amps (amperes).
Industry:Electrical equipment
NEMA has standard frame sizes and dimensions designating the height of the shaft, the distance between mounting bolt holes and various other measurements. The integral AC motor NEMA sizes run from 143T- 445T, and the center of the shaft height in inches can be figured by taking the first two digits of the frame number and dividing it by 4.
The fractional horsepower motors, for which NEMA spells out dimensions, utilize 42, 48 and 56 frames whose shaft height in inches is figured by dividing the frame number by 16.
Industry:Electrical equipment
Some motors can operate on two different voltages, depending upon how it is built and connected. The voltages are either multiples of two or the 3 of one another.
Industry:Electrical equipment
Dual speed motor whose torque varies with speed (as the speed changes the horsepower remains constant).
Industry:Electrical equipment
The resistance offered by materials to becoming magnetized (magnetic orientation of molecular structure) results in energy being expended and corresponding loss. Hysteresis loss in a magnetic circuit is the energy expended to magnetize and demagnetize the core.
Industry:Electrical equipment
In most instances, the following information will help identify a motor:
1. Frame designation (actual frame size in which the motor is built).
2. Horsepower, speed, design and enclosure.
3. Voltage, frequency and number of phases of power supply.
4. Class of insulation and time rating.
5. Application
Industry:Electrical equipment
The characteristic of an electric circuit by which varying current in it produces a varying magnetic field which causes voltages in the same circuit or in a nearby circuit.
Industry:Electrical equipment
