Sample Thermal Analysis of an Electrical Component with a Resistive
Jack M. Kleinfeld, P.E.
Kleinfeld Technical Services, Inc.
This sample analysis demostrates the ability of FEA to provide insight
to practicing thermographers by taking externally available information
and calculating what is happening inside. In this case a resistive
fault at the knife contact was modeled. The analysis provides a
relationship between the magnitude of the fault, the temperatures
observed on the outside of the component, and the temperatures achieved
on the inside of the component. As modeled, the plexiglass surrounding
only heats up a small amount. The large copper conductors, however get
quite hot both inside and outside. Because they have low emissivity,
measuring them would be difficult. The internal temperature at the
fault reaches about 200F. The exposed copper reaches about 190F
maximum. The plexiglass does not exceed 90F, except where it was
modeled as in direct contact with the copper.
Contactors are copper. Baseplate is steel. Pivot under lower
contact is ceramic porcelain. Covering box, shown as transparent, is
plexiglass. Dimensions shown are in inches.
FEA allows a better understanding of the critical temepratures that may
be achieved in areas where they cannot be measured. This simplified
sample analysis shows how FEA can supplement and extend the utility of
IR thermography, however it is ONLY A SAMPLE!! do not rely on these
If you want to expand your scope of work and your ability to help your
customers, contact Jack Kleinfeld at Kleinfeld Technical Services,
866-884-6644 toll free
© 2001 Kleinfeld Technical Services, Inc.