Conventional contactors require a replacement of contacts after approximately 10,000 to 25,000 electrical operations. However, Eaton’s new DILDC contactors require no maintenance and nonetheless provide an operating lifespan of more than 150,000 electrical operations.
As well as having extremely long lifespans, DILDC contactors can handle 1,000 volts DC per pole and current flow in both directions (bi-directional/polarity-insensitive). The contactors, which can be controlled conventionally or with a programmable logic controller (PLC), have a compact frame size that reduces costly panel space requirements. In addition, the contactors feature a wide-range coil that covers AC operating voltages from 110 to 250 volts as well as DC operating voltages from 110 to 350 volts.
Eaton’s new DC hybrid contactors are well suited to applications in the solar energy and energy storage sectors, where safe and dependable switching of DC supplies is a prime requirement. In these applications, the long operating life and bi-directional operation of the new contactors are important benefits, as is their ability to handle frequent switching operations.
To achieve their performance and long lifespan, Eaton DILDC300-600 contactors use novel hybrid switching technology. They have two mechanical contacts – an extinguishing contact and an isolating contact – connected in series. Furthermore, an IGBT (solid-state switch) is connected in parallel with the extinguishing contact. When the contactor is required to break a circuit, the current commutates to the IGBT with opening of the extinguishing contact. Next, the IGBT is turned off to interrupt the current and finally, the isolating contact opens to provide galvanic isolation. With this arrangement, under normal operating conditions neither of the mechanical contacts has to switch off the load current. This means that arcing and contact erosion are virtually eliminated.
The DILDC300-600 hybrid contactors from Eaton are currently available in two versions, with extensions to the range planned for introduction in the near future. Both versions are two-pole devices and both can be used on systems up to 1,000 volts DC. Maximum operating frequency is 100 operations per hour.
