Wednesday, August 13, 2014
A Device for Moving Product from One Place to Another
Required Drive Features:
Each application has specific requirements for I/O. Analog I/O is generally used to read process signals and output signals proportional to drive status. Analog I/O is generally Voltage (0-10V) or Current (0(4)-20mA). The type and number required by the application must match the drive.
Applications that involve multiple drives or drives controlled by PLC or other supervisory device often require communications via a defined network.
Each application has specific requirements for I/O. Digital I/O is generally used to control the drive (Start, Stop, Jog, etc.) and annunciate the drive status.
High performance applications often demand nearly instant response to changes in speed or torque commands or input status changes. The higher the dynamic response, the more capable the drive is in meeting these demands.
Motors are rated by the manufacturer for the voltage resistance of the insulation system. If this insulation system voltage is too low, voltage reflection from the drive could cause motor failure. This is particularly important if the motor is a long distance from the drive and if the motor is an older motor being retained for the application.
A squirrel-cage motor slips under load. To compensate for this, the frequency can be increased as the motor torque increases.
All applications operate over a given speed range, defined as the ratio of maximum continuous speed to minimum continuous speed.
Applications that do not require significantly more torque than the original motor rating can most often be addressed by a drive using V/Hz algorithms. Loads, such as centrifugal fans and pumps or simple conveyors, are difficult to overload and therefore do not require the performance of other motor control algorithms. Simply maintaining a fixed ratio between drive output voltage and frequency is sufficient.
Applications that depend on accurate speed to accomplish the task require a drive that can control or 'regulate' speed.
Recommended Choice: ABB ACS55 Series