Notes
• For explosion-proof applications, the efficiency of the installed protection devices has to be verified prior to
commissioning!
• The protection function of the device is the thermal overload protection of motors. In case of an overload trip, the motor
is switched off by opening the NC contact of the electromechanical overload relay.
• The safe state is an open NC contact of the device used to control the load contactor.
Mounting and commissioning
The TF42 may only be replaced by an equivalent device, marked in accordance with the regulations.
For applications protecting motors in potentially explosive areas, the device may only be used if it is configured for
"manual reset".
• Setting the rated motor current is done using the adjusting knob on the front side.
For this purpose, the rated motor current has to be adjusted on the TF42 according to the EC type examination
certificate specification and/or the type plate.
When selecting the overload relay, check its suitability by means of the trip curves and/or the trip class. Decisive values are the
ratio between the motor startup current I
A
and the rated motor current I
N
, as well as the shortest time t
E
. These values have
to be marked in the ATEX certificate of conformity or in the EC
type examination certificate
and on the type plate of the motor.
The thermal overload relay must trip within the time t
E
. This means that the trip curve from the cold state has to be below the
coordination point I
A
/I
N
and the time t
E
.
It is necessary to ensure protection against unauthorized adjustment (I
e
setting, Man/Auto reset) by sealing the cover.
The connecting cables have to be dimensioned according to the specifications and/or the applicable standards.
Safety specifications TF42
According to DIN EN 50495, the requirements for a SIL 1 and a HFT = 0 can be placed on safety equipment for categories 2G
and 2D.
The TF42 thermal overload relay can meet these requirements if used as a component of the safety equipment, e.g. in
cooperation with a suitable load contactor.
2CDC106076M6801c / 04.2016
8 - TF42
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