How do DC Contactors Work?
DC Contactors are comprised of a high current switch and a solenoid in a single enclosure. The switch provides the desired function, to turn current flow on and off. Trombetta DC Contactors provide a robust and economical means to switch high currents in low voltage DC circuits. These DC contactors are suited for applications involving voltages up to 48VDC. Current capacity varies by family with inrush capacity reaching 800 amps and continuous carry capacity reaching 225 amps for the larger units.
Accurately matching a DC contactor to an application requires proper attention to a number of details that define conditions of operation. These generally fall under three major divisions of voltages, currents and environmental factors. Adequate definition of an application specification can be a challenging task. Significant effort in creation of the application specification is justified because its' accuracy is of critical importance in achieving satisfactory durability and longevity with the most economical design. Trombetta can provide expert assistance in this most important activity.
• Addressing voltages must give consideration to the voltage being switched by the contacts and the voltage applied to the coil. These voltages need to be defined not only in their nominal condition but also at their extremes. Voltage is often a very dynamic parameter affected not only by system design but also by state of maintenance and dynamic parameters such as the current load imposed on the system at any given moment.
• Coil current requirements for the solenoid portion of the DC contactor, after brief review, typically are not of significant concern because the device controlling coil current is found to be more than amply rated. Usually consideration for current focuses on the current to be switched by the DC contactor.
• Environmental considerations need to address operating temperatures, especially the extremes, humidity, exposure to splash and spray of contaminants and what those contaminants might include, as well as shock and vibration parameters.
DC Contactors FAQs
- Bear - 225 to 300 amps
- Metals - 125 to 300 amps
- Plastic - 100 to 200 amps
- HP Plastic - 200 amps
- PowerSeal - 150 amps
- RP - 75 to 125 amps
- Defender - 200 amps (resistive) or 100 amps (inductive)
- Contact Product Support for mixed loads
- From our literature on the web site (products/contactors) determine the Nominal Coil Resistance.
- Get an OHMS meter that reads to milliohms (less than one ohm)
- Connect the 2 leads to the 2 small studs/spades (To get an accurate reading, the contactor needs to be at room temperature and not recently energized).