Carlo Gavazzi Releases New Soft Starts for Motors up to 75 HP

Carlo Gavazzi, with a rich history of automation products, including sensors, relays, timers, and monitoring devices, recently announced the release of its latest product, the RSGT series of motor soft starters. The new starter devices are designed for use on 3-phase AC induction motors with power ratings of up to 75 horsepower.

New 3-Phase Soft Starters

In order to simplify setup and operation for users, Carlo Gavazzi has included only three settings possibilities on the new soft start series: FLC (full-load current), ramp-up, and ramp-down. The new RSGT series keeps the soft starters simple to operate and program without sacrificing performance by using self-learning algorithms that can automatically adjust the soft starter’s internal parameters. Parameter adjustments allow variations for different applications and are functional through a wide range of load conditions.

The new RSGT series of soft starts can be used on many different motor sizes up to 75 horsepower. Image used courtesy of Carlo Gavazzi

A Soft Starter Designed for EU Eco-design Regulation

In July 2021, the European Union implemented a new eco-design measure for electric motors and variable speed drives. The new regulations aim to improve energy efficiency across the board by bringing manufacturers up to IE3 efficiency levels. While the measure does improve the running efficiency of IE3 electric motors over IE2 motors, it comes at the cost of increased start-up (inrush) current draw.

IE3-rated electric motors require almost twice the current of IE2 motors on start-up. This can lead to an unacceptable electrical draw, forcing many manufacturers to look for innovative solutions to the problem, and to reduce the need for oversized electrical protection devices and the larger cables required for high start-up currents. The RSGT soft starter lineup from Carlo Gavazzi looks to help reduce IE3 compliant motor start-up current draw.

The soft starters feature best-in-class current reduction on startup, including a 50% current draw reduction versus a direct online (DOL) motor start. In addition, the starters provide perfectly balanced currents on all phases, helping to increase motor efficiency. Real-time monitoring is also available via a native Modbus RS-485 interface. This data monitoring ability can help users achieve advanced monitoring capabilities for Industry 4.0 through the use of a user-friendly interface.

The control and config terminals on the largest RSGT model include Line (L), Load (T), parameter adjustments, LED indicators, dedicated I/O, and RS-485 connections. Image (modified) used courtesy of Carlo Gavazzi

Features of the RSGT Soft Start

The RSGT features high performance in a small frame, helping to reduce cabinet size or fit in places where space is at a premium. A self-learning algorithm is built into the user interface to even further simplify the setup process. The algorithm continuously learns from each startup to adjust or recommend parameters automatically according to the data it has collected. The easy-to-use interface also helps save considerable time on initial setup.

System designers can help reduce implementation costs since oversized wiring and production devices become unnecessary when using IE3 motors. Additional energy savings can be realized with the new RSGT soft starters’ use of internal bypass relays that improve efficiency. Up to 12 motor starts can be achieved in an hour, and a torque ramp down feature ensures that pumps are subject to a smoother deceleration. Specific applications for the new soft starts include blowers, ventilators, compressors, as well as fresh and wastewater pumps, which can be further protected through a ‘dry run’ feature that enables the motor starter to detect when a pump is running dry.

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