Exporting Machines and Systems to North America: Modified Requirements for Electrical Equipment.

In order to export European machines and systems to North America, they must comply with the relevant requirements placed on the electrical equipment of machines. Moeller is offering three new products for the construction of Industrial Control Panels according to UL 508A and NFPA 79.

Circuit-Breaker Actuation with the Required “Deliberate Action”.

The main switch with a rotary drive is a characteristic feature of machines in Europe. This consists of a door coupling and a mechanical door interlock. Moeller has added a further developed main switch actuator for the North American requirements for safe main switch operation to its extensive product range. The new sections of the standards for the electrical equipment of machines and systems firstly require switch actuation to be possible, irrespective of whether the switch cabinet door is open or closed. Secondly, a door interlock must be removed deliberately for the electrical equipment in the switch cabinet to be energized. The new additional NZM2-XHB-DA(R)(-NA) handles for main switches provide for the “deliberate action”, i.e. the deliberate switching, required by the standard. In order to switch on the circuit-breaker, the additional handle is rotated by 20 degrees, then pushed in this position and then rotated further to the ON position. A main switch is thus provided with two handles, two switch position indications and two locking facilities. The lockable door coupling handle provides the high protection required by UL / CSA Type 12 and 4X in North America and thus implements the switching and interlock functions when the door is closed. The new additional handle can be used on the NZM circuit-breakers and the NS molded case switches, the American switch-disconnectors with integrated short-circuit releases for self-protection.

More Efficient Motor Starters for Motors > 50 A.

Motor starter for the direct starting of higher ratings are assembled in North America from three components. Firstly a circuit-breaker with or without permanently set overload releases, secondly a contactor for automatic switching and thirdly a motor protective relay for motor protection. A new NZM..2-ME..-NA motor-protective circuit-breaker in the current range from 45 to 200 A, which overlaps the upper rating limit of Moeller's UL 508 Type E and UL 508 Type F self-protected combination motor starters, enables motor starters to be assembled with only two components. The switch has UL 489 approval as a circuit-breaker and also has other approvals for tests such as the calibration test to UL 508. The circuit-breaker is normally combined with a contactor as the second component. It allows for cost-efficient control switch construction since it saves space, reduces handling times and reduces heat dissipation. These benefits are particularly apparent when it is used in the withdrawable compartments of North American motor control centres.

Increasing the Short Circuit Current Rating (SCCR).

Another new development is the fact that the range of circuit-breakers approved for use in the USA and Canada has undergone additional tests. The switches now also meet the requirements of “current limiting” circuit-breakers. This “current limiting” feature is indicated on the switch rating labels. The let-through values tested for the common North American voltages increase the short circuit current rating (SCCR), i.e. the short-circuit withstand strength of the entire switchgear assembly. The current limitation reduces the load on downstream components to the let-through current and the let-through energy of the current limiting switch.

Moeller can provide a wide range of information and notes on the application of the North American and Canadian standards mentioned. A sample cabinet, consisting of unwired switching and protective devices will show these new features at the Hannover Fair 2008.

Moeller GmbH, 53105 Bonn
Phone: +49 (0)228 602-0
Fax: +49 (0)228 602-2275
E-Mail: presse@moeller.net
Internet: www.moeller.net
Please direct your enquiries to:
Corporate Communications, Tel.: +49 (0)228 602-2915

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