Variable Frequency Drives

November 5, 2007

3 Min Read
Variable Frequency Drives

New variable frequency ac drives and inverters are providing sophisticated control functionality and advanced software tools as part of their product offerings. These solutions include a wide range of advanced control functionality, often providing servo and vector modes either as part of the standard offering or as optional add-ons. Drives are not only providing basic control capabilities but also advanced motion control features such as position control, encoder inputs for tracking, safety features and limited amounts of I/O.

Some products are focused on the needs of specific applications, such as materials handling conveyors, and provide both environmental certifications and ready-to-use control routines that simplify programming and setup. New drives are also implementing modular designs that separate the power and intelligence in the drives. Users are able to freely selectable combinations of power sections and controllers to increase the flexibility and scalability of the drive system.


The MOVIFIT series from SEW Eurodrive provides a scalable platform for decentralized control for a range of wet and dry environments. Preconfigured control routines for horizontal and vertical conveyors provide ready-to-use functions that simplify programming and start-up. Drive parameters can be set simply without configuration tools using DIP switches or programmed over fieldbus.

Modular design makes it easy to select combinations to deliver exactly the system functionality required for an application. MOVIFIT FC provides open-loop inverters up to 5 HP. Key features include safe stop and integrated brake control, energy distribution, fieldbus or ETHERNET communication and local I/O.

MOVIFIT SC includes reversing or dual starters up to 5 HP, featuring configurable soft start and integrated brake control. MOVIFIT MC controls up to three MOVIMOT® gearmotors and includes integrated safe stop and a maintenance switch with line protection. Real-time diagnostics is enabled through the latest communication networks including EtherNet/IP, PROFINET, PROFIsafe, DeviceNet and PROFIBUS.


The E700 compact variable frequency drive from Mitsubishi Electric Automation replaces the E500 model and also provides improved performance. The E500 and E700 have the same footprint and mounting arrangements will be unchanged. All the terminal markings and parameter numbers that the two drives share have the same numbering systems.

One E700 innovation is an improved speed range. Units offer 200 percent more motor torque at 0.5 Hz, giving a smooth open-loop speed range of 120:1. Units also share the full range of communications options with the bigger F700 and A700 drives, as well as Modbus RTU.

The drive’s dedicated USB port allows direct set-up and diagnostics via a PC. Drive I/O can be remotely operated over any supported network, regardless of what the drive is doing. In smaller panel spaces, the E700 can be bookshelf mounted without a gap in between and DIN Rail mounting is also possible.


The new Sinamics S120 AC Drive from Siemens Energy & Automation offers a solution for high-performance single-axis applications. It provides an integrated modular drive system for both single-axis and multi-axis applications with the capability of running high performance servo and vector modes.

The new ac drive features an innovative modular concept that separates power and intelligence. Freely selectable combinations of power sections and controllers increase flexibility and scalability of the drive system. Multiple choices allow users to select the right controller for their needs but protect their drive investments and create possibilities for modular machine designs.

With its built-in Easy Positioning functionality, the drive is designed to handle positioning tasks for automatic assembly machines and material handling systems. The drives are available in single-phase 230V in the power range 0.25 to 1 HP and three phase 460V in the power range 0.5 to 400 HP.

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