Required Drive Features
The drive can control the rate of acceleration and deceleration of the motor and load. These features control the amount of time the drive takes to increase or decrease the output during speed control.
Requires: A drive with programmable times sufficient for the application.
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.
Requires: A drive with sufficient number and type of analog I/O.
Applications that involve multiple drives in a coordinated system often benefit from a common bus configuration. Drives are connected via their DC bus rather than the AC line. It allows energy to be shared between drives and reduces the number of components.
Requires: A drive that has the DC link terminals available and have been tested for common bus.
Digital I/O
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.
Requires: A drive that offers sufficient I/O and needed flexibility to perform all required func¬tions.
Applications that require rapid deceleration or quick stops can regenerate energy back to the drive. A dynamic brake dissipates this energy through a resistor as heat.
Requires: A drive that has an internal DB chopper and connectable resistor or has an external DB kit.
Dynamic Response
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.
Requires: A drive that meets the response demands.
High Maximum Frequency
Most applications operate at speeds at or below the motor rated speed (typically 1800 RPM (60Hz)) for the US and 1500 RPM (50Hz) elsewhere. Other applications such as high speed grinders and winders need to operate at much higher speeds, sometimes with special motors.
Requires: A drive that has a high enough maximum frequency to allow outputs high enough to achieve the needed motor speed.
Overload Torque
Applications may require varying degrees of overload capacity for starting, accelerating, or intermittent duty. This overload capacity must be supplied by the drive as current and by the motor as torque.
Requires: A drive that has sufficient overload capacity.
Power Loss Ride-Through
Applications that control a continuous process cannot afford to stop because of short power outages or dips. The process must continue to run through these outages, typically 2 to 3 cycles long.
Requires: A drive that has sufficient power loss ride-through capability.
Preset Speeds
A drive is typically speed controlled using a potentiometer or analog input device. If specific repeatable speeds are required, parameters can be used to preset operation of the drive at a pre-determined speed using a digital input.
Requires: A drive that provides preset speeds.
Reconnect to a Spinning Motor (Flying Start)
Applications with significant inertia and low friction tend to coast when stop commands, power interruptions or fault conditions occur. Many of these application require that when the condition disappears, the load must be reconnected at the 'coasting' speed / direction and returned to normal operation.
Requires: A drive with spinning motor reconnect or 'flying' start.
Slip Compensation
A squirrel-cage motor slips under load. To compensate for this, the frequency can be increased as the motor torque increases.
Requires: A drive that provides adjustable slip compensation.
Speed Range (20:1)
All applications operate over a given speed range, defined as the ratio of maximum continuous speed to minimum continuous speed.
Requires: A drive that can produce the needed torque and speed torque regulation (accuracy) over the required speed range.
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