7.16.2 Motor protection (thermal monitoring)
In order to protect against overheating and impermissibly high temperatures
at the actuator, PTC thermistors or thermoswitches are embedded in the
motor winding. The thermoswitch is tripped as soon as the max. permissible
winding temperature has been reached.
The actuator is switched off and the following signals are given:
.
LED 3 (thermal fault) on the local controls is illuminated.
.
Status indication S0: operation mode OFF/LOCAL = FLT + NR
.
Status indication S0/S6: operation mode REMOTE = FAULT IND.
.
Status indication S1 in the display: THERMAL FAULT.
The motor has to cool down before the operation can be resumed.
Depending on the par
ameter setting, the fault signal is either automatically
reset or the fault signal has to be acknowledged.
Acknowledgement can be made:
.
via the Reset button in selector switch position LOCAL
.
or via the Profibus, Reset Bit of process representation (for this, the
selector switch must be in Remote control position).
Viewing the motor protection
This value is set in the factory.
Æ
Via the menu to parameter:
MAIN MENU (M0)
CONFIGURATION (M4)
SETUP (M41)
MOTOR PROTECTION (M4108)
Default values: Non Ex actuators = THERMAL CONT.(AUTO)
Ex actuators = THERMISTOR (RESET)
È
Description of the parameter settings:
THERMAL CONT. (AUTO)
Automatic reset after the motor has cooled down.
Not possible for explosion-proof version ACExC 01.1
THERMAL CONT. (RESET)
Manual reset. After the motor has cooled down the fault must be reset,
either
.
via the Reset push button at the local controls, or
.
with the RESET command via the fieldbus.
If required the thermal overload relay has to be reset manually. To this end,
remo
ve the cover on the back of the AUMATIC and operate the Reset but-
ton on the thermal overload relay.
THERMISTOR (RESET)
Manual reset. After the motor has cooled down the fault must be reset,
either
.
via the Reset push button at the local controls, or
.
with the RESET command via the fieldbus.
THERMISTOR (AUTO)
Automatic reset after the motor has cooled down.
Not possible for explosion-proof version ACExC 01.1
85
Actuator controls
Manual AUMATIC AC 01.1/ACExC 01.1 Profibus DP
VIEW
MOTOR PROTECTION
THERMAL CONT. (AUTO)
C:ESC
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