PTC thermistor triggering system needed

The motors are equipped, as standard, with PTC resistors in the windings in accordance with DIN 44081. PTC thermistor triggering systems must therefore be used, otherwise the conformity will no longer be met. The PTC thermistor triggering systems should fulfil the following conditions:

• Type-examination tested in accordance with Directive 2014/34/EU.
• Labelling according to the directive, at least II (2) G for use in gas atmospheres.

The PTC thermistor triggering system must be matched to the PTC thermistor inserted in the winding in accordance with DIN 44081 (see rating plate).

Tripping must occur:

• in the event of excess temperatures on the PTC thermistors, i.e., in the stator winding of the connected motor.
• after a short-circuit in the PTC thermistor circuit.
• after a wire break in the PTC thermistor circuit.
• after the supply voltage fails in all three external conductors.

Once all causes of faults have been eliminated, the connected motor must not start up again automatically. It may only be switched on again manually (restart interlock).