What is the normal current of the three-phase motor of 3KW
The electric current formula of the motor Three-phase motor power 1 kw per phase 2 (ampere) current (ampere) = power (kilowatt) watts) * 1000/1.73 * force rate * efficiency Remark: power rate: 0.85; Efficiency: the rated current of 0.853 kilowatt motor is 6 times.
Normal ac motor, including FM motor, is not allowed to be plugged. By the external characteristic curve of ac motor, the ac motor will generate a "subversive current" burning machine when plugging. At this time the converter, if the vector is controlled, the motor is plugged and the torque current is not controllable. I've done this experiment. If the speed of more than 5 hz, can control the torque current (size can be smooth adjustment), and, using the encoder feedback is better than not using encoder feedback.
So, for common communicators, the open loop control and the motor plug are not able to control the torque. If the servo ac motor is adopted, the closed-loop speed control, Angle control and position control can be blocked. For ordinary motor, you can consider, mechanical lock or jammed, mandatory locked-rotor, has completed the user's technical requirements, and then let go of mechanical plugging turn institutions, for the next process control. Ac motors are easily burned if plugged or missing. Must first understand the motor winding dc resistance of the dc resistance is under 15 Ω (motor dc resistance is smaller, the greater the power from less than 1 Ω), if the blocked or lacks when the motor has lost its ac impedance, so only under 15 Ω loop resistance of the motor, then the current can want to how much (380 v, 0.35 KW, for example: 380 present 15 = 25, 25 A was greater than the motor coil current over-current value). Often lack of phase, so the motor over-current protection (by the hand of my circuits are lack of phase, over-current protection), the first one but problems is that the current changes, this will protect the motor.
