Remarks for usage of relay terminals EL26xx

Analyze operation conditions It is extremely important to observe the technical specifications if fault-free operation is to be guaranteed.

Any time that the stated parameters are exceeded, damage ranging from premature contact ageing up to fused contacts can result. If relays are to be used in a control system the expected operating conditions must be analyzed with great care. Switching capacity, service life (operating cycles) and the number of switches per minute must be considered. Appropriate protective circuits must be used to protect the relay contacts from excessive voltage peaks such as can occur when switching inductive loads (contactors, motors etc.). This allows switching frequencies nearly equal to those appropriate to resistive loads to be achieved. Arcing time when switching DC loads are significantly longer than those for comparable AC voltages (zero crossing); material flow can result. If the terminal is used to change the direction of inductive loads, adequate dead-times during the switch-over must be provided, in order to avoid temporary short-circuits.

For the -0010 variants applies:

The relays internally of these terminals would be switched near to the zero voltage crossing of an AC supply. Hereby the lifetime of the outputs is no longer dependent by the absolute lifetime of the relay. The result of an exemplary long term test with the following boundary conditions represent that:

• Each channel of a terminal EL2622-0010 (or KL2622-0010 respectively) switches cyclic one time per second a beforehand complete discharged capacitive load of approximately 40 µF (without any additional resistor in series) to 230 V AC, whereof a permanent current of approx. 4 A is resulting.
• After abortion of the test over more than 200,000 switching cycles per channel the expected lifetime of the terminal outputs are above them of the relays.
• Under the same test conditions but without connection of the neutral wire that disables the operation of the zero voltage detection, the relay was out of order after less than 10 switching cycles.