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3. THERMAL OVERLOAD RELAY
3-1 STRUCTURE AND OPERATION
3-1-1 Standard Type (1E) and Phase Failure Protected Type (2E)
(1) External structure
Fig. 21 External structure
(2) Internal structure
Fig. 22 Internal structure of standard type (1E)
thermal overload relay
(This contains high-performance bimetals
and contact mechanism applicable to the
thermal overload relay (2E).)
Fig. 23 Internal structure of thermal overload relay (2E)
(This 2E thermal overload relay is the same
as the standard type as regards the external
structure , but different from the internal
structure in the differential mechanism.)
Current setting mark
Operating circuit terminals
Current setting knob
Reset button
(Concurrently used for
change of reset methods)
Test trip lever Trip indicator
Main circuit terminals
(Power source side)
Main circuit terminals
(Load side)