Hybrid motor starters in a compact package

The new Contactron series of motor starters combine the advantages of the classic electromechanical relay with modern semi-conductor tech-nology. The result is a highly functional solid-state reversing contactor that facilitates project planning and wiring, requires a minimum of space in the control cabinet and ensures maximum system availability with almost wear-free switching. 

Of interest to machine builders, system integrators, panel builders and MCC manu-facturers across all sectors, the new Contactron product family from Phoenix Contact provides 3-phase motor control with up to four functions in one compact module. With versions ranging from a simple '1 in 1' direct starter up to the complete '4 in 1' reversing starter with motor protection and Emergency Stop, there is a product for virtually every application.

So why would you use the Contactron motor starter in place of the traditional method? A motor that needs to be controlled in both forward and reverse directions traditionally requires two contactors and a motor protection relay to be wired together. If an emergency stop is needed then an additional emergency-stop contactor is also required. Firstly this way of doing things needs at least four separate components, and all these four components take up about 135mm of Din-rail space. 

For 3-phase AC motors up to 4kW, the Contactron '4 in 1' combines the four functions of forward and reverse run, overload protection and emergency stop contactor in one module measuring only 22.5mm wide. This gives a space and wiring time saving of approximately 75% in both cases, which is a significant cost benefit.

Hybrid switching

At the heart of the Contactron is a hybrid switching technology. It is this technology that allows the device to be much smaller in size than comparable mechanical contactor solutions. The hybrid nature of the product comes from a microprocessor-controlled com-bination of rugged relay technology and wear-free solid-state technology that leads to 'gentle' switching. 

In simple terms, the motor load is started using the solid-state switches, while a set of electromechanical relays operate in parallel to carry the load and allow the solid state components to turn off. This sequence happens in reverse when the load is switched off or reversed. 

In practical terms this means wear-free fast switching, a reduced load on the relay contacts, the elimination of contact bounce, excellent high vibration rating, and built in output protection. As a result of this technology the heat sinks that are usually required are not necessary, which in turn allows for a reduction in size of the devices. 

The complete family of Contactron are available with 24V DC control or up to 230V AC control input voltages. The overcurrent protection func-tionality is also highly flexible which means that one or two modules can be inventoried and monitoring can be set for all sizes of motors up to 4kW. 

There are three different current versions available: 0.6A, 2.4A and 9A with the new 0.6A power class aligned to motors rated up to 0.18kW and allowing low motor currents to be set precisely. The Contactron range also holds SIL 3 and PL e rating that means it can easily fulfil international safety directives. Additionally they also hold ATEX approval and are ideally suited for use in the chemical and petro-chemical sectors.