View Single Post
  #14  
Old 03-23-2020, 04:10 PM
Cecil McKenzie Cecil McKenzie is offline
Registered User
 
Join Date: Feb 2011
Location: Emporia, KS
Posts: 502
Cecil McKenzie is on a distinguished road
Sky no worries. i know the literature says the MDRs fail open rather than closed, i use MDRS that are normally open. On several occasions I have had melt downs in my anneallers. I changed the MDR and everything was fine. I have also experienced touching an element when the controller was off and received a 120 volt shock. I took this to mean that one side of the relay was closed allowing me to get shocked. The elements were not hot as per temperature but were energized by one side of the relay. Now you say that is not possible but in my case it seemed very possible.

Be that as may I am trying to find something that will work better for me.

I have been reading some about SSRs on line. One page said
mdrs are not allowed in many countries now and wonder what some other countries are using instead of MDRs,
https://www.process-heating.com/arti...mercury-relays

Still trying to figure this out. Appreciate all input.
Reply With Quote