a) List and briefly explain the selection of VSD settings based on their application. (9 points...

Question

a)   List and briefly explain  the selection of VSD settings based on their application. (9 points each with 1 mark)   b)   Which one of these settings  can be used to control the starting torque?

David · Accepted Answer

VSD ADVANTAGES, DISADVANTAGES, SELECTION CRITERIA AND INSTALLATION TIPS AND TRICKS
Different type of VSD (Variable speed Drives)
**Speed Control
A fundamental principal of a Variable Speed Drive is to adjust the speed of an electric motor. The basic command frequency for Variable Speed Drives is normally from 0 Hz to 50 Hz, but with the average capability to be adjusted up-to 400 Hz. If the base frequency of a motor is 50 Hz then the final speed will be 8 times the base frequency of the motor with the command frequency set at 400 Hz. 
At High frequency set points mechanical failure may occur due to the mechanical design of the motor bearings normally rated at the design speeds of 2, 4, or 6 poles. At high frequency command speeds, care should be taken as torque loss may be experienced. See our example in the tips and tricks section.
**Torque Control
Basic torque control is possible in an open loop system; however, the actual system response required must be considered. In an open loop system the Variable Speed Drive monitors the motor current and adjusts the voltage to perform torque control, depending on the installation, if the current of the motor does not vary sufficiently very inaccurate results will be obtained.
**Position Control
With the aid of an optional interface card most Variable Speed Drives have the ability to be used as a low cost position controller. Items to be taken into consideration are the dynamic response of the motor and control system. As a rule of thumb an open loop system with standard squirrel cage induction motor is approximately 400 radians /second, in a closed loop system with a standard squirrel cage induction motor and feedback approximately 600 radians /second. A full servo system is approximately 1000 radians / second. 1 radian / second = 9.55 rpm or 2π radians (rad.

a) List and briefly explain the selection of VSD settings based on their application. (9 points each with 1 mark) b) Which one of these settings can be used to control the starting torque?

Solution

Answer To This Question Is Available To Download

Related Questions & Answers

Submit New Assignment