MOV (metal oxide varistor) selection for a relay for over voltage protection

[pikamaps]

I need to provide a voltage surge protection for a relay input which has a maximum voltage rating of 250VAC. The relay im using is: Songle SDR-05VDC-SL-C
datasheet: **broken link removed**

i have gone through some documentation of MOVs and i have narrowed down my options and have decided to use Bourns MOV-07DxxxK Series of MOVs. :idea:
http://www.bourns.com/docs/Product-Datasheets/MOV07D.pdf

out of which i feel i should use MOV-07D271K for my application. if anyone has worked with MOVs before please do help me out here, let me know if my MOV selection is correct. If its wrong then please let me know which one i should choose and why. :???:

HELP!


-thanx from Prasanna

 

[erikl]

What's the normal operating voltage in your application for this relay?

 

[pikamaps]

250VAC as shown in the datasheet

 

[erikl]

250VAC as shown in the datasheet

In this case I'd suggest to use the MOV-07D391K instead, it's the suggested MOV for this Max. Continuous r.m.s. Voltage.

The MOV-07D271K already starts to pass tangible current at voltages above 175VAC (= r.m.s.), so probably @ 250VAC has a not inconsiderable continuous thermal power dissipation (roughly estimated: ¼W).