Trip units according to Directive 2014/34/EU ("Explosion protection directive") are always
necessary to monitor the temperature sensors.
4.5 External fan cooling air quality
The cooling air is only permitted to have weak chemically aggressive properties and must only
have low levels of oil or dust.
4.6 Interlock circuit for the external fan motor
For machines with external fans, install an interlock circuit that prevents the main machine
being switched on if the external fan is not operational.
Explosion hazard if the temperature class is exceeded
If a force-ventilated machine is operated without a separately driven fan, the temperature class
or the maximum surface temperature of the machine can be exceeded.
In an explosive atmosphere, there is a risk of an explosion. This can result in death, serious
injury or material damage.
● Install an interlock circuit that prevents the machine from being switched on if the separately
driven fan is not switched on/is not operational.
● Do not commission the machine without a separately driven fan.
4.7 Interlock circuit for anti-condensation heating
If the anti-condensation heating is operated while the machine is running, this can increase the
temperatures inside the machine.
● Install an interlock circuit that switches off the anti-condensation heating once the main
machine is switched on.
● Only switch on the anti-condensation heating at the earliest two hours after the machine has
been switched off.
WARNING
Explosion hazard due to excessively high temperatures
If the anti-condensation heating is switched on directly after the machine is switched off, the
temperature class or the maximum surface temperature of the machine can be exceeded.
In an explosive atmosphere, there is a risk of an explosion. This can result in death, serious
injury or material damage.
● Only switch on the anti-condensation heating at the earliest two hours after the machine
has been switched off.
Preparing for use
4.7 Interlock circuit for anti-condensation heating
1MB5 SH 400/450
28 Operating Instructions, 05/2019, A5E45959221A
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