How Do Motor Starters and Electrical Contacts Work

Video Transcript:

This is a Furnas Contactor. Furnas is now owned by Siemens. This Furnas industrial contactor is in the Furnas Innova Plus Series. This Furnas GP40 contactor has 3 poles.

We’ll remove the Furnas GP40 cover to expose the electrical contacts. The green or start button on a pushbutton station is depressed to energize the system. The electrical current goes to the coil. A contactor coil is simply copper wire wrapped around a magnetic core.

Electrical Contacts, Electrical Circuits Start Electric Motors

The outside covering around the wire and core can be either be wound or encapsulated with a special plastic like the coil in this contactor. When the contactor coil becomes energized it pushes or, in this case, magnetically pulls a metal plate downward in the contactor. The movable contacts are attached to the plate, mounted in a holder, which then contact or mate with the stationary contacts. When they mate, the circuit is completed and will start one or a number of motors used in the steel -making process.

So, a contact is simply an electrically-controlled switch that completes or interrupts a circuit. A motor starter is a contactor with overload relays added to each circuit for overload protection. The contactor and overloads are most often mounted in a metal enclosure or box like this Most control equipment in a steel plant is larger than the NEMA contactor we’ve shown here. Some IEC contactors are mounted on rails. IEC stands for International Electrical Code and is usually associated with European and Asian designs.

Wholesale Electric Motor Contacts, Coils and Motor Brushes

Repco is proud to be part of a process that provides quality products to the marketplace. We’ve been supplying replacement contacts to industry for more than four decades to help keep machines running and are your experienced choice for industrial control parts.