- 産業: Electrical equipment
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A current that flows only in one direction in an electric circuit. It may be continuous or discontinuous and it may be constant or varying.
Industry:Electrical equipment
A motor using either generated or rectified D.C. power (see Motor definition) . A DC motor is usually used when variable speed operation is required.
Industry:Electrical equipment
A definite purpose motor is any motor design, listed and offered in standard ratings with standard operating characteristics with special mechanical features for use under service conditions other than usual or for use on a particular type of application. (NEMA
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 centre 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, utilise 42, 48 and 56 frames whose shaft height in inches is figured by dividing the frame number by 16.
Industry:Electrical equipment
A drip-proof machine with ventilating openings guarded (with screens) as in a guarded motor.
Industry:Electrical equipment
An open motor in which the ventilating openings are so constructed that drops of liquid or solid particles falling on it, at any angle not greater than 15 degrees from the vertical, cannot enter either directly or by striking and running along a horizontal or inwardly inclined surface.
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 commonly available electric power supplied, an AC generator and is distributed in single or three-phase forms. AC current changes its direction of flow (cycles).
Industry:Electrical equipment
The relationship between the operating and rest times or repeatable operation at different loads. A motor which can continue to operate within the temperature limits of its insulation system, after it has reached normal operating (equilibrium) temperature is considered to have a continuous duty (CONT.) rating. One which never reaches equilibrium temperature, but is permitted to cool down between operations is operating under intermittent duty (INT.) conditions such as a crane and hoist motor which are often rated 15 or 30 min. duty.
Industry:Electrical equipment
