Drive enclosures resist ursine intrusion

Edited by the Engineeringtalk editorial team Nov 11, 2003

WEG's experience and ability to provide control solutions in the worst of atmospheric conditions was tested recently - by a bear.

WEG's experience and ability to provide control solutions in the worst of atmospheric conditions was tested recently - by a bear.

The bear in question decided that a panel supplied by WEG and installed in the north of New Mexico could hold a potential meal, so he decided to try and break through the twin-door, glass-fronted unit.

Fortunately, unlike many car windows that succumb annually in North America to hungry bears, the WEG enclosure complete with its single-phase drive survived the encounter without damage and the bear went away empty handed.

The result of this impromptu product testing is that WEG now commonly refers to its special outdoor enclosures as "bear proof" units.

The origin of the bear proof enclosure owes much to WEG's experience of supplying control solutions in some of the most demanding operating environments in the world: notably in South America, in mines high up in the Andes and oil pipelines extending through deserts and jungles.

Although highly prized for its bear resisting qualities, the panel design was originally a specific answer to the harsh climate in the Americas, where outdoor installations are routinely subjected to a menu of rain, sun, sleet, snow, hail, animals and insects.

To protect against these natural hazards the panels are designed with twin glass fronted doors.

These enable the enclosure with its drive and associated equipment to operate at high latitudes, in regions subject to snow and very low temperatures, and also in regions with high ambient temperatures up to 40C.

At low temperatures a thermostat turns on space heaters within the panel to prevent frost damage.

At high temperatures an internal cooling system is automatically activated to cool the panel.

In addition, a positive pressure system is used to deny air entry in different parts of the panel, cooling air entering only through the air filters.

The combination of these measures ensures that the panel equipment stays in good order, and that the double tempered glass window in the panel door stays demisted, providing the system user with easy visual monitoring of the variable speed drive keypad and all system indication lights.

The success of the WEG's special panel in the wilds of north New Mexico has led to an order for several hundred for use in the same region.

Not only are the panels special so are the drives, the majority being single-phase, 460V AC, 75kW units, with some single phase 230V AC (22kW) versions also employed.

"We do not have too many bears in the UK, but we do have enough applications that require special protection against the elements", said Graham Perry, WEG UK's Product Manager for Drives.

"The proven combination of the 'bear proof' enclosure and our CFW-08 and CFW-09 ranges of drives makes sense for any outdoor applications where the equipment is continually exposed to rough weather or to rapid changes in climate".