Quote Originally Posted by CocaColaKid
The small relays are using the reverse-biased diode for suppression which seems to work really good. Just wish it would work for the AC relays as well.
Joe may be right.

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Large relais have AC or DC coils. If you use a relay with a DC coil you can use
the same solution you have used for the small relay.

Suppressing Relay Coil Transients:
http://relays.tycoelectronics.com/ki...transients.stm

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Example of relay with "AC coil" with built-in surge suppressor:

700-R -RM Sealed Switch Relays:
http://www.ab.com/en/epub/catalogs/1...196/index.html


(SEE "Surge Suppressor" under TAB Accessories).
http://www.ab.com/en/epub/catalogs/1...4196/tab5.html

(From the web page).
When the circuit to a DC operating coil is opened, the inductive energy stored in the coil can generate very high transient voltages. With the addition of the appropriate surge suppressor, the stored energy is absorbed and dissipated limiting the voltage spikes. A surge suppressor is not required with AC 700-R or -RM relays because the AC operating coil transients are suppressed by a full wave rectifier connected to the coil.


Luciano