Given a hybrid DC relay, I've been wondering if contact erosion is occurring (albeit at a slower rate), or if the design eliminates this entirely.
(Assume that there is no snubber or other contact protection)
I'm presuming that there is erosion for the following reasons:
According to my old H W. Ott book ("Noise Reduction Techniques in Electronic Systems" Ch.7), there are minimum voltages (9 to 20 V) and currents (10s to 100s of mA) where contact arcing will occur. With a hybrid relay, once the the solid-state switch (or relay) turns on, the EMR contacts stay below the voltage minimum due to the low voltage drop of the device. However, once the EMR is closed (or opened) the contact current minimums (e. g., rated > 1 Amp) will be exceeded. The reason? The contact's inductance in conjunction with the contact bounce during closure (opening?) will resulting in arcing once the current flow exceeds the minimum rating.
So it suggest to me that there is contact erosion (albeit much less than a standard EMR).
Is this correct, or am I missing something?