Danfoss is introducing a new and very compact IP55/IP66 A4 enclosure for its VLT AutomationDrive, HVAC Drive and Aqua Drive frequency converters with power ratings up to 4kW. Compared with the existing A5 enclosures, the dimensions have been reduced by 33 per cent. Nevertheless, the power components fulfil demanding requirements, even in applications with high overload torques, long motor cables or ambient temperatures up to 50degC.
The new A4 enclosure is available in IP55 (NEMA 12) and IP66 (NEMA 4X) versions. Power components rated at up to 4kW are available for input voltages of 380-480/500V (three-phase). Furthermore, the versatile power module design enables the units to be used on machinery or conveyors requiring high over-torque capability. Similarly, the new unit can also be used with motors with normal over-torque, such as fans or centrifugal pumps.
Danfoss achieved this size reduction through the use of modern, high-efficiency components, together with a completely new cooling technology. All of the elements of a typical VLT drive configuration - such as an RFI filter compliant with EN 55011 Class A1/B, a mains interference suppression choke and the brake module - are integrated in the unit to avoid expenditure on the installation of external components.
During development, special attention was paid to accessibility and time-saving installation. For example, the mechanical fastening points are readily accessible from the front, and the fasteners can be operated using automatic tools. Terminal clamps are arranged to enable installation of the cabling with the simplest possible work sequence, and the cable entry in the base is available with a choice of metric or non-metric threads. Additionally, all terminal clamps are fitted with a protective cover and the necessary fittings are included with the unit.
To enable the inverters to be readily adapted to individual applications, two A/B extension slots are provided. They can be used for communication interfaces such as Profibus, Profinet, Ethernet I/P or CANopen, and a module for additional inputs and outputs can be installed. Danfoss supplies the converter fully assembled and tested.
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