Micro drive promises big drive features

Danfoss has entered the fiercely competitive micro-drive market with a product derived from its larger VLT AutomationDrive and sharing many of its characteristics. The VLT Micro Drive will be available in single- and three-phase versions rated from 0.18-7.5kW, in three frame sizes.

Danfoss is hoping to redefine the largest segment of the global drives market, which accounts for 60-70% of all drives sold (by volume). Unlike some rivals, which are simply cost-reduced versions of larger drives, Danfoss says it is offering a high level of "performance density", including big-drive features such as a built-in logic controller, AC and DC braking, and automatic motor adaptation.

The Micro Drive is programmed using the same VLT software as its larger siblings, and shares the same terminal numbering system and the same hot-pluggable display and control panel. Settings can be copied via the panel to program multiple drives.

The Micro Drives, which incorporate "intelligent" heat management and a novel heatsink design, are said to operate with 98% efficiency and can be used in ambient temperatures up to 50°C. An automatic energy optimisation function is claimed to cut energy consumption by 5-15% in HVAC applications.

The smallest frame size measures 150 x 70mm and 148mm deep. The drives can be mounted side-by-side to save cabinet space.

As well as a built-in electronic thermal relay, which replaces external motor protection, the Micro Drives incorporate short-circuit, over-temperature and earth-fault protection. They can deliver 150% of rated torque for up to a minute, and support Modbus RTU and RS-485 communications.

The drives are being built by Holip, the Chinese drives manufacturer that Danfoss bought last year.