DuraKool--Mercury contactor failure mode

[Rudy]

Today, I believe I had a mercury relay (DuraKool) intermittently fail ON.

Is it possible for a mercury relay to fail ON? I can see how it can fail to close...but stick ON????

 

[Randy]

Today, I believe I had a mercury relay (DuraKool) intermittently fail ON.

Is it possible for a mercury relay to fail ON? I can see how it can fail to close...but stick ON????

Yes, I've seen the Durakool relay stick On. I found that the MDI mercury relays are a better relay. I've never had a MDI rely fail yet.

 

[OurTown]

Today, I believe I had a mercury relay (DuraKool) intermittently fail ON.

Is it possible for a mercury relay to fail ON? I can see how it can fail to close...but stick ON????

 

[Rudy]

Follow up question....

The mercury contactor in question controls either a 1/2 or 3/4 HP trolley motor in my automatic bay. At 120v...the amp draw is approx 10 or 13 amps depending upon which sized motor I use.

My question...

The mercury contactors are VERY reliable. I see that they are being replaced with SSR Solid State Relays....often called "hockey pucks".

Would a 25amp (or even 40amp) SSR be just as reliable?