Motor protection circuit breakers for versatility
[2008-12-23 17:04:40]
With interchangeable plug-in trip blocks, optional high-capacity contact modules and a wide range of accessories, the PKZ2 motor protection circuit breakers from Moeller Electric provide a wide range of convenient, dependable and exceptionally versatile starting solutions for motors rated up to 18.5kW. Suitable for use as manual motor starters without the need for any additional components, the basic PKZ2 units feature a rotary operating handle which clearly shows the status of the breaker. They can be fitted with trip blocks to suit motor full-load currents from 0.4A to 40A and, since the blocks can be changed in seconds, alterations in motor sizes during commissioning or plant modifications present no problems.
Another advantage lies in increased safety during maintenance work where removal of the trip block provides a visible isolating gap.
The trip blocks provide fully adjustable overload and short-circuit protection, and are available in three- and four-pole versions.
In addition to motor protection types, trip blocks that are optimised for system protection are also available.
For applications where the motor is to be controlled automatically, Moeller Electric offers a convenient remote operating unit.
This is available with a common supply and control connection for use in conventional control systems, or with a separate control connection which can be used with inexpensive low-current outputs from programmable controllers.
Where frequent motor switching is needed, the functionality of PKZ2 circuit breakers can be enhanced by fitting high-capacity contact modules.
Available in AC- and DC-operated versions, these function in the same way as a contactor, allowing the motor to be started and stopped without switching the breaker on and off.
Their use also increases the switching capacity to 100kA at 4 00V, with type '2' coordination.
A base is available for mounting contact modules separately from the breaker.
Together with an accessory mechanical interlock, this enables reversing starters to be implemented using only PKZ2 components.
Among the many other accessories available for use with Moeller Electric's PKZ2 motor protection circuit breakers are trip-indicating auxiliary contacts which differentiate between short-circuit and thermal trips, standard auxiliary contacts, an undervoltage release, and a shunt trip unit.
The range also includes an IP65 door-mounting handle assembly which allows the breaker to be operated manually without opening the panel door, and insulated enclosures for surface mounting which provide a flexible and attractive option for standalone motor starting applications.
