Smallest fully integrated intelligent soft starter

Edited by the Engineeringtalk editorial team Dec 21, 2000

Cutler-Hammer's new 24V dc-controlled, fully integrated soft starter is 30 to 80 per cent smaller than current offerings, and also safer and more cost-effective

Cutler-Hammer, the world-leading manufacturer of industrial controls and circuit protection equipment, has launched the industry's smallest fully integrated Intelligent Soft Starter.

Available now, the new range of Intelligent Technologies (IT) Soft Starters are a minimum of 30 per cent smaller than all current industry offerings - and in some cases, up to 80 per cent smaller - making them ideal for any situations where space is at a premium, in particular the retrofit market.

The IT Soft Starters are available in four frame sizes, from 65x187x168mm to 280x420x195mm.

The new Cutler-Hammer Soft Starters have been developed as part of an Intelligent Technologies (IT) programme, aimed at meeting the needs of OEMs and end-users for smaller, safer, more cost-effective power controls.

The new 24V dc-controlled, fully integrated Soft Starters also have more reliable interfacing with PLC and distributed control logic systems, use safer operating voltages and simplify compliance to safety standards.

"Using soft starters can save companies a lot of money as they reduce stress placed on mechanical parts of the control gear, lowering maintenance costs and reducing down-time resulting from mechanical breakdowns," said Terry Price, Applications Engineer at Cutler-Hammer.

"Now, the new Cutler-Hammer IT Soft Starters are smaller than ever before, use less power and simplify compliance to safety standards, making them ideal for a wider range of industrial applications.

They are particularly suited to the retrofit industry, where installations cannot exceed the existing space available and component size is of paramount importance." Fulfilling the industrial requirements of compressors, blowers, fans, pumps, mixers, crushers and grinders, the Soft Starters combine powerful microprocessors and separated control and logic circuits to dramatically reduce their control power requirements.

This removes many obstacles that have prevented greater use of 24V dc control power, such as power supply costs, transistor and hard contact ampere ratings and voltage drop on long cable runs.

The new IT Soft Starter design also integrates both the bypass contactor and overload relay functions into one compact unit, eliminating the need for separate hard-wired devices and saving panel space and wiring costs.

In addition, the full bridge 6-SCR design does not require the use of isolation contactors, allowing a dramatic reduction in size - a 135A device can now fit into an 18-inch Motor Control Centre (MCC) bucket and weighs only nine pounds, making it 30 - 80 per cent smaller than all other current industry offerings.

The IT Soft Starters' kick start feature provides an adjustable pulse of up to 550 per cent of current, or 85 per cent torque, for a time of 0 to 2.0 seconds, supplying an extra 'push' for stubborn inertia loads.

Also, to avoid sudden stops with high friction loads, the soft stop feature allows an extended coast to rest by ramping down the voltage to the motor.

IT Soft Starters also include overload, stall, jam, phase loss, phase reversal, shorted SCR detection and SCR over-temperature protection.

And for quick and easy configuration, IT Soft Starters have incorporated the potentiometers, DIP switches and LEDs in an easy to use device-mounted display.

Further features and benefits of the new range of IT Soft Starters include: • Reduced stress on the mechanical drive system, increasing life and reliability of belts, gear boxes, chain drives, motor bearings and motor shafts • Reduced stress on the electrical supply due to high starting currents, meeting utility requirements for reduced voltage starting and eliminating voltage dip and brown-out conditions • Reduced shock on the driven load, reducing occurrence of jolting on conveyor, pump cavitation and water hammer in pipes • Fully-adjustable ramp time and starting torque for optimal starting performance, providing enough torque to accelerate the load while minimising both mechanical and electrical shock to the system • Selectable start ramps, both voltage to traditional loads and the current limit ramp, for reducing max to start current on differing start loads.