This core of a contactor or relay is made of laminated steel in order to ___________________________

• A. Increase magnetic flux
• B. Withstand high temperatures
• C. Minimize mechanical wear
• D. Reduce Eddy currents

Answer: (D)

Eddy current losses are a major inefficiency in the magnetic core of AC devices. When the magnetic field in the core changes, circulating currents are induced inside the conductive steel. Those eddy currents heat the core and waste power. Using thin, insulated steel laminations breaks up these current loops, dramatically increasing the resistance to them and keeping the currents small. The result is much lower core heating and better efficiency, which is exactly why laminated cores are used in contactors and relays. The other options aren’t the primary purpose of lamination: increasing magnetic flux depends on material properties and geometry, not the laminations themselves; resisting high temperatures or reducing wear aren’t the main roles of the core laminations.