Introduction to DC Contactors
Introduction to Dc Contactors
DC contactors usually adopt modular design, requiring the minimum number of parts to assemble the required number of contact paths and contact forms (normally open, normally closed, and switch); The contact has a high breaking voltage and cross-field arc extinguishingfunction, with a breaking voltage of up to 1000VDC, making it suitable for programmable or uninterruptible power supplies, forklifts, electric vehicles, and machinery used in construction.
Structure and Components
The DC contactor consists of Electromagnetic System, Contact System, and Arc Extinguishing Mechanism:
- Electromagnetic System: The coil is energized (DC) to generate a magnetic field, and the armature is then actuated to open or close the contacts.
- Contact System: It includes static and moving contacts. In most cases, they are made of durable, highly conductive materials such as silver alloy, which can withstand frequent switching and arcing.
- Arc Extinguishing Mechanism: When the contacts are separated, the arc is extinguished by magnetic blowout or arc slots to prevent damage to the contacts.
Principle of Operation
DC contactors operate on the principle of electromagnetic induction. When DC current flows through the coil of a contactor, it generates a magnetic field that attracts the movable iron core, causing it to move and actuate the contacts. Specifically, when the coil is energized, the magnetic field generates electromagnetic attraction that attracts the movable iron core, causing the normally closed contacts to break and the normally open contacts to close, thereby breaking the circuit. When the coil is de-energized, the electromagnetic suction disappears, the movable iron core is reset under the action of the spring, the contacts are restored and the circuit is broken.
Technical Features
- Voltage and Current Ratings: Designed for DC voltage ranges (e.g. 12V-1000V) and currents up to 3000 amps.
- Powerful Arc Management: Quenching technology solves DC arc generation problems.
