The new Varispeed G7, is the first general-purpose VSD setting a new global standard to feature 3-level control method which approaches sine wave output voltage.
Features of the 3-level control method
This new control method solves the problem of micro-surges normally associated with conventional 2-level control. It provides the solution to common problems such as damage to motor insulation due to surge-voltages and electrolytic corrosion of motor bearings caused by shaft-voltage. Noise and leakage current is reduced up to 50%. This new technology provides low acoustic noise that is difficult to achieve with conventional designs. The low surge-voltage eliminates the need for surge voltage protection for the motor. Longer cable lengths can be achieved without the need for any chokes to be installed.
High-level control performance
The new control technique improves torque characteristics with 150% at 0,3 Hz for open loop vector control, providing improved control response with closed loop flux vector control using encoder feedback, more than 150% torque at zero speed is possible. The unique high speed current vector control provides excellent motor speed tracking of rapid speed reference changes (up to 40 Hz). Speed functions allow accurate control of output torque, protecting the machine from sudden load fluctuations. High-speed search is another feature that allows for rapid recovery after momentary power losses regardless of rotational direction. In addition to conventional dynamic auto-tuning, a new static auto-tuning is available in order to optimise the performance of the motor, by matching motor characteristics to the VSD.
Safety and protection functions include 5-level, high-precision, high-speed current control and IGBT protection functions which enhances overall VSD reliability. Continuous operation is ensured by suppressing nuisance over-current trips, restart after momentary power loss, stall prevention and fault retry options.
User-friendly and flexible
The Varispeed G7 is designed for and conforms to global environmental demands and standards. Energy saving features eases the burden on the environment. All models above 18,5 kW are equipped with DC reactors to improve the power factor and are supported by 12-pulse supply input, which when connected to a dual star-delta secondary transformer, reduces the harmonic current distortion factor to 12%.
The standard 5-line digital display programming and copy unit makes it simple to enter parameters and monitor drive performance values. The quick program mode allows for rapid basic setting of application parameters. The last changes can be checked at once by the verify mode. The 'modified constants' menu is a powerful diagnostics tool, which only displays parameters that are different to the initial factory settings.
The Varispeed G7 is modular, easy to install and commission. This is complemented by detachable control terminals and cooling fan units. Cooling of the unit is well managed by the facility to mount the drive with the heat sink and fan units protruding from the rear panel. The electronic section inside the panel does not require any additional ventilation and is contained in a dust free environment. This type of installation offers significant benefits regarding maintenance and heat problems normally associated with VSDs installed inside enclosures.
Global specifications and standards
All Varispeed VSDs are fully compliant with RS232/RS485Modbus communication protocols and supports optional communication interface cards such as Profibus DP, DeviceNet, Interbus-S, CC-Link, CANopen, ControlNet, and LONworks. All Varispeed VDSs comply with every major American and European certifications and are certified by UL/cUL and CE markings.
For more information: Varispeed, 011 466 0830, erika@varispeed.co.za
| Tel: | +27 11 312 5252 |
| Email: | enquiries@varispeed.co.za |
| www: | www.varispeed.co.za |
| Articles: | More information and articles about Varispeed (A Division of Hudaco Trading) |
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