A contactor is an electromechanical switch used to switch an electrical power circuit. Unlike manual switches, contactors can be handled remotely and are developed to handle high currents, making them essential in many industrial applications. Their most common application involves control of electric motors. Other applications include lighting, heating, capacitor banks, and other electrical loads. In the world of industrial automation, overseeing the direction of electric motors is necessary for various applications. Reversing contactors is key to achieving this control and ensuring that machinery operates efficiently and safely.
What is a Reversing Contactor?
A reversing contactor is a specialized assembly that allows the direction of a three-phase AC motor to be changed. This is achieved by combining two standard contactors with a mechanical interlock unit, ensuring that both contactors cannot be engaged at the same time. When one contactor is energized, the motor runs in the forward direction; when the other is energized, the motor comes to a halt and runs in the reverse direction. This setup is essential for frequent and reliable forward and reverse motor operation or direction switching applications.
Difference Between Reversing and Non-Reversing Contactors
The primary difference between reversing and non-reversing contactors lies in their configuration and functionality. The non-reversing contactor controls the motor in a single (forward) direction. In contrast, a reversing contactor uses two interlocked contactors to change the motor’s direction by swapping/interchanging two of the three-phase power lines. In this case, the connection on the load side would be phase L1 to L3, L2 to L2, L3 to L1 as seen in the diagram below. Both configurations offer similar safeguards regarding motor protection, but reversing contactors provide the added functionality of directional control.
Fig 1:- Reversing Contactor Schematic
Applications for Reversing Contactors
Reversing contactors are being used in several industrial applications for controlling/changing the directions of conveyor systems, pumps, elevators, cranes and other industrial machinery.
Introducing NOARK’s Ex9CR and Ex9CSR Series
NOARK Electric offers Ex9CR Series Standard IEC Reversing Contactor and Ex9CSR Series Reversing Mini Contactor designed for demanding forward/reverse operations of three-phase AC motors. These are multi-contactor assembly connected by an electrical and mechanical interlock that ensures only one contactor closes at a time. They are available in various ratings and are suitable for inductive motor applications from 9A to 500A (standard reversing) and 6A to 12A (mini reversing) full-load amps. They can be panel-mounted with screws, or DIN-rail mounted, providing installation flexibility. This series offers high reliability with extended mechanical and electrical life.
The Ex9CR and Ex9CSR compact design makes them ideal for applications where space is limited. They are compliant with international standards such as IEC, UL and CSA, ensuring safety and performance. Like most NOARK products, the Ex9CR and Ex9CSR series have a 5-year limited warranty.
The Ex9CR and Ex9CSR series offer a range of accessories to enhance functionality, which includes: –
1. Front and Side Mount Auxiliary contacts
2. Mechanical Interlocks
3. Surge Suppressors
4. Reversing kit
In comparison to alternatives from competitors, the Ex9CR and Ex9CSR series stand out due to their compact design, a wide-range electronic coil with built-in surge suppression, and comprehensive accessory options. The 5-year limited warranty further underscores NOARK’s commitment to quality and customer satisfaction.
More About NOARK’s Reversing Contactors
Now that you understand the importance and applications of reversing contactors, consider integrating NOARK’s Ex9CR Series 9A to 500A Standard IEC Reversing Contactor and Ex9CSR Series 6A to 12A Reversing Mini Contactor into your operations for efficient and safe motor control.
For more information about our Ex9CR and Ex9CSR series, contact a NOARK sales representative at nasales@noark-electric.com, or visit our website at www.na.noark-electric.com to explore our full range of products.
