difference between ac open loop , vector control, servo modes
Simply .. in OPEN-LOOP u don't get FEEDBACK form the system but in closed loop ,, u get feedback and use it to correct the system performance !!!
confusing task. seek with bing and yahoo. this could help!
With open loop you just send a voltage at a set frequency from your inverter to the motor. You only measure the current to see if the motor is having trouble or not. You could have the motor turning erratically or not at all if there is a problem in the connection. The inverter will have the same output regardless. With Vector control you normally need a normal motor with some kind of feedback like an encoder on the shaft. This way you can determine the speed that the motor actually runs at and correct accordingly if it doesn't respond like you want it to. If the motor doesn't turn correctly for any reason it will trip on the inverter. You can also run on vector control with an encoder mounted on a pulley or belt or product that the motor is controlling. Servo mode is a pretty precise control and you can control the motor to a specific position and hold it at a position without turning. You can get a normal AC motor to react in this matter but the accuracy is not as good as an actual servo motor. 5% against 1%. You need to have an encoder on the shaft of the motor for this. In general you run on open loop unless you want to control the inverter in special application.
