During the model development, thermoelectromotive force
E of this additional electron source has been also included.
Acceptable accuracy of temperature measurement has been rated as "Class 1," which is the highest precision (least tolerance) under the standards of the International Electrotechnical Commission (IEC), providing almost same thermoelectromotive force
characteristic as pure platinum currently used on the negative electrode.
Due to relative movement and clamping force between a contact brush and contact ring a thermoelectromotive force
is generated, caused by a friction, which depends to some extent on combination of used materials.