Thermal overload equation 1

[MakingAComeback]

Would anyone happen to know the equation for the tripping time of a North American Class 20 thermal overload relay? If so would you mind enlightening me?

 

[winterpeg1]

Try out these URL's,

http://library.abb.com/global/scot/...870852573a300738595/$File/1SXU106043B0201.pdf

http://www.geindustrial.com/products/brochures/239.pdf

http://www.fournais-ing.dk/download/xm1_e.pdf

http://ieeexplore.ieee.org/Xplore/login.jsp?url=/iel5/28/4504109/04504127.pdf?arnumber=4504127

 

[MakingAComeback]

Thank you Mr. Winterpeg.

The Fournais download your provided was very helpful.

Much obliged.