|
|
ENGINE CHOICES
Certain steps are standard when selecting a motor screw compressor. The motor must accommodate the design of the compressor load on a permanent basis. Even the potential of motor overload (when the suction pressure rises above the calculated values, for example) can be processed by automatic compressor unloading valve.
When choosing an electric motor of a drive of the screw compressor, power and torque of the engine during start-up must be carefully assessed. Although the valve is completely empty position, the moments of inertia of the rotor is relatively high. The torque delivered by the motor should be 20% higher than required by the compressor in the entire speed range experienced during launch. The draw of the current startup time can be five to seven times that occurs during the full speed, depending on the type of starter. Because the heating of windings is proportional to the square of the electric current, the heating rate of the engine is 25 to 50 times that of normal operation. The duration of this high current period should be short, selecting a drive motor with an adequate starting point...
|