Required Drive Features
The drive can control multiple independent rates of acceleration and deceleration for 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 multiple independent accel / decel times.
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.
Droop
Specifies the amount of base speed that the speed reference is reduced when at full load torque. Use the droop function to cause the motor speed to decrease when an increase in load occurs. This function is normally associated with master/follower application.
Requires: master/follower firmware must be specified.
Dynamic Brake
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.
Long Motor Cable Length
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.
Requires: A drive that has the lowest dv/dt or long cable mode of operation.
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.
Position Regulation
A feedback device on the motor or machine, typically an encoder or resolver, feeds position information to the drive. The drive compares this information to a desired setpoint and adjusts its output to place the load in the desired position.
Requires: A drive that offers this control method when positioning without a separate positioning controller is needed.
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.
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
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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