Overload protective devices for electric motors of type of protection Ex e – do you know that?

According to EN 60079-7 the temperature rise for machines with cage rotors shall be limited. This can be done by using a current-dependent safety device.

In this case the fault tolerance according to the temperature rise of the motor is 0. A safety device with SIL 1 and a hardware fault tolerance of 0 is necessary to fulfil the requirements of Category 2 equipment. This has additionally to be considered, when designing a complex overload protective device for an Ex e motor according to EN 60079-7.

NOTE The general requirements for Ex e overload protection devices are given in EN 60079-7 and EN 60079-14

Keep up good work!



Leave a Reply