Electrical network the no-load current of the motor general examples of 30% of the additional current squirrel-cage motor: general situation makes a third of the extra current in the motor power is very small, sometimes the no-load current of the motor will surpass 50% of the additional motor current, and of high power motor, the no-load current also may be less than 20% of the additional current, synchronous motor is lower. At the same time the more motor pole logarithmic no-load current. Formula: motor no-load current, capacity by about eighty percent; Number of xinda sixty percent less, the old small number of very many kilowatts. Clarify formula is the rapid calculate motor no-load current of detailed numerical formula, it is a lot of the test data. It fit & other; The no-load current of the motor general throughout is the 1/3 of the additional current &; 。 At the same time it fit practical experience: & other; The no-load current of the motor, not beyond the capacity of kw number can be used throughout the &; The rule (Refers to the maintenance of old, small capacity motor)。 Formula & other; About eighty percent capacity throughout the &; Refers to the general motor no-load current value is the number of additional capacity motor kw 0. About eight times. No-load current of medium-sized, 4 or 6 pole motor, is the number of motor capacity kw 0. Eight times. New series, large capacity, small number of level 2 of the motor, the calculated no-load current & other; The number of xinda sixty percent less & throughout; ; For the old, old series, small capacity, the number of large more than 8 pole motor, the no-load current, press & other; Is a little much kw number & throughout; Approximate calculation, namely, no-load current value equal to the number kilowatts capacity, but is generally less than kilowatts. Using the formula to calculate the no-load current of the motor, and motor of book designation, the field is there are some errors, but the formula to calculate values can completely meet the electrical requirements in daily work. No-load current of the motor is bigger reason is roughly as follows: 1, the stator winding circle number less than normal. 2, set and larger air gap between the rotor. 3 and low quality core silicon steel sheet (Factory for the nonconforming or use fire to the core when split winding burn out)。 4, lack of core length or the overlying false form useful lack of length. 5, by the overlying pressure is too large, will iron core of the insulating layer of silicon steel sheet crushed or the original insulation insulation performance can not meet the requirements. There is an error in June, winding wiring. Should such as three-phase star connection is actually a three phase Angle, no-load current is 3 times more than normal, with parallel route than planning values, such as: should be 1 road series is actually a two-way parallel, should be 2 parallel is 4 road in parallel, current will increase the number of multiple at the moment. 7, extra frequency is 60 hz motor ventilation with 50 hz ac point, at the moment the no-load current of 1 will be normal. More than 2 times. 8, power supply voltage higher than the additional value, the additional voltage attachments, no load current and the square of the voltageAnd even more than 3 power)Is proportional to the, so add the no-load current will far outweigh the voltage added.
