New testing procedure defines an electrical property for moulded inductors

Würth Elektronik has developed a new testing procedure for determining the maximum operating voltage of moulded inductors. The electronic and electromechanical components manufacturer introduces developers to the electrical property of dielectric strength and what happens if it is exceeded in an application explained in Application Note 126 (www.we-online.com/ANP126). The moulded inductors from the Power Magnetics product portfolio (e.g., WE-MAPI, WE-XHMI, WE-LHMI) are now successively supplemented with the value of the maximum operating voltage Vop as a new parameter in the specifications.

The company defines the maximum operating voltage Vop in its data sheets based on the new testing procedure. This represents the voltage at which an inductor can be operated continuously in the application without impairing performance, risking damage or overheating the inductor. The operating voltage is, therefore, a limit value for the input voltage, up to which the inductor can be utilised reliably in an application without irreversible damage.

The test concept examines the behaviour of inductors up to their voltage limits under realistic conditions in a DC-DC full-bridge converter (voltage transients of up to 60V/ns and frequencies of up to 2MHz). The approximate voltage limit is first evaluated using a short-term test. The operating voltage is then defined on this basis and verified in a long-term test.