Patent ID: 7116538

Claim:
A modular overload relay comprising: a) a base overload relay module having: i) a first housing supporting first terminals and second terminals, the second terminals receivable by a contactor; ii) current conductors for conducting current from the first terminals to the second terminals; iii) solid-state analog circuitry monitoring the current in the current conductors to produce an overload signal being a function of the current, the overload signal receivable by the contactor to open the contactor upon detection of an overload signal; iv) an electrical connector extending from a wall of the first housing and communicating with different points in the solid-state analog circuitry; b) an added function module having: i) a second housing that is separate from the first housing and attachable to the wall of the first housing of the overload relay module; ii) a second electrical connector joining with the electrical connector of the overload module when the added function module is attached to the wall of the first housing; and iii) ancillary circuitry communicating with the solid-state analog circuitry to augment a function of the solid-state analog circuitry; wherein the base overload relay module is operable as an overload relay without being engaged with the added function module.