Nord SK500E

The Nord Drivesystems SK 500E series frequency inverter family.

The SK 500E inverter range from NORD Drivesystems is available for motors with rated powers from 0.25 - 132 kW (160 kW from the middle of 2014). Due to its very compact design it is ideally suitable for space-saving installation in control cabinets. Features such as: 
- sensorless current vector control, which provides constant speed with fluctuating loads and very high starting torques, 
- 200% overload reserve, which ensures greater safety for crane and lifting gear applications, 
- an integrated brake chopper for 4-quadrant operation, 
- an integrated line filter as the basis for optimum EMC performance are included in the basic equipment of the entire range, as well as a PID or process controller.
These controllers automatically control your application. There is a choice of devices with an integrated 24 V mains unit or a separate connection for the control board supply. Devices with an external supply have the advantage that even when they are switched off, the parameter data can be accessed and communication is possible via bus interfaces. In addition, such an inverter enables selfcontrolled evacuation runs, which is an enormous safety benefit, no just for lifting gear drives. The SK 51xE and SK 53xE models support the "Safe Stop" function according to EN 13849-1 (up to the maximum safety category 4, stop categories 0 and 1), whereby the SK 53xE version with its built-in POSICON function is ideally equipped for all positioning tasks (relative and absolute). The top model SK 540E /SK 545E supports convenient free programming functions close to the drive unit in accordance with IEC 61131 and also enables the operation of synchronous motors with permanent magnet excitation. Even with their various functions the inverters have the same physical dimensions.

User friendly.
- Easy adaptation to communication systems through plug-in technology units. 
- Quick and simple diagnosis with easily visible LED indicators. 
- Technology units available for display, operation and parameterisation:
Easy to read large LCD display in 14 languages (optional).
Simple operation and parameterisation thanks to logical parameter structure and intuitive layout of control elements.
Versions for control cabinet installation.

Nord Drivesystems SK 500E series drive extensive basic equipment.

Load monitor.
- Monitoring of load torque depending on the output frequency
- Individual adaptation of load monitoring to protect the system from overload in particular frequency ranges.
Link circuit coupling.
Intermediate circuit via terminals for all versions:
- Energy saving effect with balanced motor and generator operation 
- Elimination of brake resistors possible.
Lifting gear functions.
- High precision current vector control for rapid and precise load take-up 
- Integrated brake chopper to divert generated energy to a brake resistor (optional) 
- Brake management for optimum control of an electromagnetic holding brake for wear-free actuation of the brake.

Servo mode.
- High precision speed control
- Highest possible acceleration through direct feedback of the actual speed to the frequency inverter and therefore:
Full torque down to standstill (speed 0)
Digital speed controller withwide range of settings.

Precision and logic.

POSICON.
Frequency inverters with integrated POSICON functionality are able to determine the actual position of the drive unit via appropriate interfaces. Incremental encoder inputs (TTL / HTL) or absolute encoders are available as interfaces via CANopen (from SK 540E and above sine wave encoders, SSI, BISS, EnDat 2.1 and Hiperface are also available). In addition to conventional point-to-point positioning (absolute positioning), POSICON also provides the facility for relative positioning of endless axes as well as various technology functions (rotating platform "with travel optimisation", synchronous operation and flying saw). By means of the standard position POSICON position memory and features such as "teach in", "reference point run", "reset position", "offset position", "target window positioning" and "S-ramp", the frequency inverter is able to perform a complete, independent positioning control. The tasks for the external control are therefore reduced to the starting pulse and communication of the target position (via digital I/O or at the field bus level). The frequency inverter can even undertake monitoring of the positioning process and reporting of the operating status.
Applications:
- Lifting gear / storage and retrieval devices with precise position control
- Bridge trolleys for material handling systems / portal cranes with synchronisation function for all driven axes 
- Rotating platform functions for tool magazines on machine tools
- Flying saw: Control and parallel guidance of a saw on a moving object.

PLC
In most cases the frequency inverter is controlled by means of an overriding PLC. However, the use of an external PLC requires additional space and installation expense in order to implement communication between the PLC and the participants (e.g. frequency inverters). In many systems with relatively simple drive functions, the expense required soon becomes unacceptable. This is where the SK 540E / SK 545E come into their own. Their integrated Instruction List (IL) based PLC functionality (based on IEC 61131-3) is specially designed for drive functions. With a computational performance of approx. 200 IL commands per millisecond and a total of 1280 commands in the program, this control unit is able to undertake many tasks in the field of the frequency inverter. Inverter inputs or information from a connected field bus can be monitored, evaluated and further processed into appropriate setpoint values for the frequency inverter. Visualisation of system statuses and the input of special customer parameters is possible by means of optional equipment (ParameterBox, NORDCON software).
Applications:
- Control / regulation of one or more devices by the inverter.