Soft start/stop units offer firm control of torque

Motion Control & Drives

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November 2002 Motion Control & Drives

Designed to control asynchronous motors with power ratings from 4 to 1200 kW at voltages of 230 to 415 V a.c. or 208 to 690 V a.c. Telemecanique’s range of Altistart 48 soft start/soft stop units combine high performance, simplicity of installation and ease of integration within control systems.

Based on the 'TCS' concept, a patented torque control system, the Altistart 48 authorises firmly controlled starts and decelerations, thus ensuring protection of both the motor and the machine at all times, including the acceleration and deceleration periods. Acceleration and deceleration is easily set up through simple adjustment of the ramp times.

The range of devices includes models rated for each standardised motor power rating, making for ease of choice. Wiring is made easy through removable control terminals and commissioning is quick since all common application parameters are factory preset as standard.

Remote access is made possible by the presence of a variety of communication modules, including Ethernet TCP/IP, which ensures that the Altistart 48 can easily be integrated into modern control systems such as Schneider Electric's own Transparent Factory TM architecture. In addition to an integrated Modbus protocol, other connection options are available, such as FipI/O, Profibus DP or Device Net modules.

The range complies with international standards such as IEC, UL, CSA, DNV (marine and off-shore), etc and the devices are suitable for any commercial and industrial soft starting application.

When applied to fan, compressor and conveying applications, soft starters minimise mechanical shock loading which is known to lead to belt slippage and machine component wear. In addition, the Altistart 48 continually monitors for overloads and underloads (detection of broken belts and drive chains, clogging or jamming of the product, etc), limits the current and voltage drops on starting, permits 'catch on the fly' restarting of free-wheeling fans and detects any incorrect direction of rotation.

The devices also cater for sensitive pumping applications, in which the management of hydraulic transients, gradual fluid pressurisation, reduction of water hammer and pressure surges is essential. Pipework is thus protected by minimising violent pressure changes.

Being factory preset, the Altistart is immediately ready for use. However, if precise adjustment of the motor parameters is required, a terminal located on the front panel can be used to customise the settings using a simple and intuitive menu.

The Power Suite program, common to all Telemecanique variable speed drives in the Altivar range, also performs this type of adjustment in addition to configuration and assistance with set-up. Power Suite consists of a multilingual software workshop for PCs, PC pocket terminals (such as a Palmtop PC) and a complete connection kit.

Additional functions integrated in the Altistart allow extended application flexibility through: cascaded starting and deceleration of several motors; configuration of a second motor with different application parameters; 'smoke extraction' duty (disabling of thermal protection devices if fire is detected); display of electrical values, load status and operating time; configuration of numerous I/O (four discrete inputs, two discrete outputs, one analog output, three relay outputs), etc.

For more information contact Schneider Electric South Africa, 011 254 6400, [email protected]

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Motion Control & Drives

Soft start/stop units offer firm control of torque

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