15.2 TRIAC

Background

A defective Triac is detected, when a current of more than 500mA is measured for more than 5 seconds in a switched off channel, and the main conductor is on. In this case a message with the measured current is added to the event journal and the channel is set on error. The main conductor is switched off to protect attached equipment. Operation after such an event is only possible if the error is cleared and the main conductor is switched on again. If the error persists the Triac has to be exchanged, or the channel load has to be removed. In this case an operation of the device using only the remaining channels is possible.

Replacement procedure

• Screw out the fixing screw to the heat sink (screws M3, TX10).
• Remove the defective triac.
  The easiest way is to cut off the legs of the triac with a side cutter and pull them out individually.
• Remove residues of the old thermal grease with a cloth from the heat sink.
• Place a small dot of thermal grease to the centre of the back of the new triac.
• Insert the triac as deep as possible into the 3 spring cage terminal and press it firmly against the heat sink. In this way the legs bend into the right shape for an optimal contact surface of the triac on the heat sink.
• Fasten the triac with the screw on the heat sink again.