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Fan equipped with thermal protection,
without output control
Figure 19 shows the connection of the RP Ex fan in a sim-
ple ventilation device without fan power regulation. This co-
nnection method ensures full thermal protection of the fan
by means of thermistors, ATEX certified thermistor relay*
and STD protection relay. The wiring shown in the pictures
also allows the fan to be switched on and off manually using
the buttons on the STD protection relay.
After pressing the black button marked "I" on the STD protection relay,
the fan will start and the button will remain in the pressed position, which
signals the operation of the fan. Pressing the red button marked "0" stops
the fan.
When the motor overheats above 130 °C due to overloading, the resistan-
ce of the thermistors K1, K2 in the motor winding increases several times.
ATEX certified thermistor relay* increased resistance detects and opens
contacts 11, 14. Opening contacts 11 and 14 opens the control coil of the
contactor, which disconnects the power supply of the overheated fan RP
Ex and disconnects the control coil of the STD protection relay circuit TB1,
TB2. The STD reacts to this state by turning off the power supply. After
cooling down, the engine will not start by itself. The operator must confirm
the fault by resetting the thermistor relay and then pressing the black
button marked "I" on the STD protection relay.
* ATEX certified thermistor relay, e.g. manufacturer type U-EK230E
Ziehl-Abegg. The suitability of using a different type must be consulted with the ma-
nufacturer.
Fan with output control
and protection controller
Figure 20 shows the connection of an RP Ex fan in a ventilation
device with air output regulation using a TRN controller with an
ORe 5 controller.
This connection method ensures, in addition to fan power options
in levels "0" to "5", also its protection by means of thermistors,
ATEX certified thermistor relay and contactor. The wiring shown in
the pictures also allows the fan to be turned off and on manually
from the ORe 5 remote controller, as well as externally with any
switch (explosive gas detector, room thermostat, pressure switch,
hygrostat, etc. in Ex design - terminals PT1, PT2).
By pressing the button on the ORe 5 controller, the fan starts at the selected power
(1 to 5) and the light indicating the operation of the fan lights up. The condition for
the operation of the fan is a closed switch connected to terminals PT1, PT2 and
closed terminals 11 and 14 of the ATEX certified thermistor relay* connected to
the control coil of the contactor. With the switch on terminals PT1, PT2, the fan is
stopped and started without further connections, so that after starting it runs at the
power set to ORe 5. If this option is not used, it is necessary to connect terminals
PT1, PT2. When the fan is overloaded, as a result of the motor overheating, contacts
11, 14 of the thermistor relay open, then the contactor drops out and the power
supply to the motor is interrupted. The controller reacts to this condition by turning
off the engine power supply and turning off the fan operation light. After cooling
down, the engine will not start by itself. First, you need to reset the thermistor relay,
then by switching the controller to the "0" position, confirm that the fault has been
removed (unblocking). Then, by switching to position "1" to "5", the fan will start at
the set power. With this connection, the "0" position must not be blocked on the ORe
5 remote controller.
14
A
B
Figure 19 – Fan connection
Zone 1
BNV
230 V / 50 Hz
ATEX
certified
thermistor
relay*
Figure 20 – Fan connection
Zone 1
BNV
230 V / 50 Hz
ATEX
certified
thermistor
relay*
230 V / 50 Hz
3× 400 V / 50 Hz
* ATEX certified thermistor relay, e.g. type U-EK230E
manufactured by Ziehl-Abegg. The suitability of using
a different type must be consulted with the manu-
facturer.
RP Ex
STD
2,5 V=
Cable mechanically
protected against
damage
3× 400 V / 50 Hz
E.g. explosive gas
concentration detector
RP Ex
TRN
24 V=
ORe 5
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