Pump motor can be widely used in different fields, in addition to flammable, explosive or corrosive gas occasions, such as transportation, mixing, printing, agricultural machinery and video processor applications, but also can be used with machine tools, pumps, blowers, compressors and other supporting equipment.
According to the structure classification, pump motor should be divided into horizontal motor and vertical motor. Since the working characteristics of the water pump are relatively small starting torque, relatively small starting frequency, relatively long continuous operation time and so on, most of the pump motors are squirrel-cage rotor asynchronous motors or synchronous motors.
The choice of pump motor should be based on the shaft power selection; Motor power is greater than shaft power by one grade; For example: shaft power is 15KW, the choice of motor should be: 18.5kW as for the use of several pole motor, according to the actual working conditions. 2 pole motor is generally used in the case of slightly high head and small flow (the calculation is more complex). 4 - pole motor can be selected for large flow and small head. 4 or 6 pole motor is selected for large flow and low head. When choosing a six pole motor, the power can be reduced by one grade according to the shaft power.
P = pgQH/(n1n2)
Where: P -- power, W; P = density of water, p=1000 kg/m^3; G -- gravitational acceleration, g=9.8m/s^2; Q -- flow rate, m^3/s; H -- head, m; N1 -- pump efficiency; N2 -- motor efficiency.
While developing high efficiency motor, using frequency conversion speed regulation technology is another effective measure to save energy. High efficiency motor and frequency conversion motor tests put forward higher requirements on the function and performance indexes of the test equipment. In order to accurately obtain the efficiency of the motor, the widefrequency power analyzer with microprocessor and frequency conversion power transmitter/sensor with higher accuracy level should be used.
