About Klöckner Moeller: From Switchgear to Industrial Automation

Klöckner Moeller, later known as Moeller, is a German industrial brand associated with electrical switching, motor protection and machine control. Its history connects the development of switchgear, contactors and PLC/HMI systems. Today, that legacy also continues within Eaton's portfolio under the Moeller series name.

Origins and changes of name

Franz Klöckner founded the company in Cologne in 1899 to manufacture electrical switching devices. Hein Moeller joined in 1911 and developed a three-phase oil-insulated contactor in 1912. He should therefore not be described as a joint founder in 1899.

The company adopted the Klöckner-Moeller name in the 1940s and became Moeller GmbH in 1999, its centenary year. These changes explain the different names found on older equipment and catalogues.

Motor control and protection: DIL and PKZ

One of the brand's core areas is starting, stopping and protecting electric motors. DIL contactors are an important part of this portfolio. In Eaton's range, families such as DILM, DILL, DILMP and DILK address motor loads, lighting, different pole configurations and capacitor switching. A current rating alone does not establish suitability; load type, utilisation category and coil voltage also matter.

The PKZ motor protection family dates back to 1932. Current PKZ devices combine overload and short-circuit protection and can form motor starter combinations with suitable DIL contactors. Auxiliary contacts provide status information. An overload relay, a motor protection circuit breaker and a contactor perform different tasks. Protection devices respond to electrical faults, while the contactor provides normal switching control.

Circuit protection and operator controls

NZM is a moulded case circuit breaker family in the Moeller/Eaton portfolio. This product area addresses power distribution and circuit protection beyond individual motor control. When comparing thermal-magnetic circuit breakers and electronically tripped versions, consider current, operating voltage, pole count and breaking capacity together. Not every NZM model has the same trip unit.

RMQ-Titan represents the physical interface between an operator and a machine. This includes pushbuttons, selector controls and indicator lights. With M22 and M30 products, the correct combination of actuators, contact blocks and lighting elements matters. Together with switching products such as cam switches, these families show that the brand extends well beyond electronic controllers.

From 1998 to easyE4: Programmable control

easy control relays were introduced at the 1998 Hannover Fair. They brought logic previously implemented with multiple timers, counters and auxiliary relays into a compact programmable device. The easy concept can therefore be understood as a practical bridge between conventional relay circuits and PLC applications.

The range developed from easy400 to easyE4; the easyE4 generation was presented at the Hannover Fair in April 2019. A smart relay allows control logic to be changed in software. For those familiar with contacts and coils, Ladder logic offers a recognisable starting point. However, newer communication and software features must not be assumed to exist on every older easy model.

4 April 2008: Acquisition by Eaton

Eaton acquired the Moeller Group on 4 April 2008. This should be described as an acquisition rather than a merger of equals. Eaton's 2008 annual report identifies Moeller as a Germany-based supplier of electrical components for building applications and industrial controls for industrial equipment. The acquisition brought those capabilities into Eaton's electrical business.

It is also inaccurate to say that the Moeller name disappeared entirely. Current DIL, PKZ, NZM and RMQ products can carry the Eaton Moeller series designation. However, continuity of a brand's legacy does not mean that every historical model remains in production. For the wider corporate background, see our About Eaton page.

Automation and connectivity under Eaton

XC300 modular PLCs, XN300 I/O systems and XV300 touch panels are examples of complementary products in the current automation portfolio. XC300 provides CODESYS 3 programming and Ethernet interfaces. PLCs and I/O process field signals, while the HMI provides the operator interface. SCADA belongs to the broader context of monitoring and supervisory control.

SmartWire-DT connects control components through a communication system designed to simplify panel wiring. It carries control and status information for compatible contactors and operator devices; Eaton also provides integration options for third-party PLCs. In this way, automation develops from operating individual devices towards exchanging information between them.

Motor control also extends beyond switching a motor on and off. Variable frequency drives manage operating speed, while contactors and protection devices perform other functions. Considering these groups together helps explain the technical scope from electrical power to machine motion.

Understanding the technical legacy

Our interpretation of this history is a progression through switching, protection, programmable control and connectivity. These layers complement one another on a production line: protection devices respond to electrical faults, contactors switch loads, controllers manage operating sequences and operator interfaces display information. This distinction explains why equipment from different periods cannot usefully be compared under a single generic label of “automation device”.