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Press Release
New MCCBs Break with Tradition
![[picture of NZM3 units]](images/nzm3.jpg)
A new modular
range of moulded case circuit breakers from Moeller Electric is packed with
new features, including an unusual double break contact for switching.
The units are easy to install, with a very compact footprint and have an optional data communications interface. Called the NZM1, 2, 3 and 4, the breakers are ideal for applications from cable protection to guarding motors and generators where fast switching is a benefit.
In the event of a short circuit, new switching technology ensures rapid protection by using repelling magnetic power to push the contacts apart in a fraction of the sine wave. New materials and geometry combine to achieve not only the fast switching, but also a subsequent reduction in heat dissipation, which is an advantage when breakers are installed in control panels. A reduction in the number of moving parts lengthens service life.
Evidence of the research and development that has gone into the new NZM range is the rationalisation of the mechanical design, with just four frame sizes of switch covering from 25kA up to 150kA. The breakers all use auxiliary contacts, taken from the existing and widely stocked Moeller RMQ-Titan range, which can be fitted very simply and quickly from the front of the breaker during commissioning. There is also a common base plate for all rotary handles, reducing the number of different handles that may otherwise be required. In short, the NZM range simplifies specifying and ordering and reduces spares stocking requirements.
Installation is quick and easy, thanks to features such as the ability to mount all accessories from the front of the units, uniform spacers that enable flush front mounting and a range of cable connections to suit any cable management needs.
One innovation that will appeal to systems designers is the ability to link the circuit breakers to other controls. An optional data management interface allows the current, just prior to tripping, to be recorded and also enables identical configurations to be set quickly in series applications. The breakers can be networked, using Profibus, to communicate fault, maintenance and diagnostics data with PLCs, HMIs and SCADA systems. This feature simplifies the management of complicated distribution systems.
Specialised applications, such as those where elevated temperatures are encountered, are covered by the breaker's ability to operate, without derating, at temperatures up to +50°C. For marine and offshore installations, the highest switching capacity of 150kA is suitable.
