Page 1 of 2 12 LastLast
Results 1 to 13 of 25
  1. #1
    Join Date
    Dec 2012
    Location
    columbus, OH
    Posts
    2,190

    Isolation relay?

    At we have some clear cased relays i was told were isolation relays. I placed this thread in general because i have no clue as to their application. By just looking at them they appear to be like most relays 2 3-way switches controlled by a coil, only difference from your run of the mill relay that i observed is a very high resistance across the coil (in the Kohm range) but im not positive they are even functional. Any insight as to how they work, or their application would be appreciated.Name:  ImageUploadedByTapatalk 21361738049.412576.jpg
Views: 1844
Size:  12.5 KB

  2. #2
    Join Date
    May 2012
    Location
    Upper Michigan
    Posts
    3,589
    There ice cubes. There should be a sub base for then also. I see them a lot but usually use RIB.

  3. #3
    Join Date
    Dec 2012
    Location
    columbus, OH
    Posts
    2,190
    Quote Originally Posted by Joehvac25 View Post
    There ice cubes. There should be a sub base for then also. I see them a lot but usually use RIB.
    Could you be more specific please.RIB?sub base?

  4. #4
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
    Posts
    14,915
    It looks like a fairly common DPDT relay.
    The only question is what the col voltage and contact ratings are.
    Typically the contact ratings are fairly low, <5A.
    Often, there will be a socket(sub base) mounted in the unit, or as part of a control board, that the relay plugs into, or it will just be mounted wit a screw in the tab, with wires plugged directly onto the terminals.

    That style of relay has frequently been used as a defrost relay to switch the outdoor fan off, and energize the reversing vlave.
    I've seen them used a lot in commercial packaged and split systems when there are are are 2 different control voltages being used in the system.
    If more government is the answer, then it's a really stupid question.

  5. #5
    Join Date
    Mar 2009
    Location
    Mid-Mo
    Posts
    3,596
    You see those a ton in building control work. Ice cube relay, 6 pin, 8 pin, etc. Hopefully you can still read the writing on it and that'll tell you all the goods.

    Some even have lights that light up in the top to tell you they are made.

  6. #6
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
    Posts
    14,915
    Quote Originally Posted by Core_d View Post
    Could you be more specific please.RIB?
    Relay In a Box.

    http://ribrelays.com/
    If more government is the answer, then it's a really stupid question.

  7. #7
    Join Date
    Dec 2011
    Location
    Australia
    Posts
    18
    Maybe you are referring to what I know as a lockout relay? A lockout relay is often used to stop a air conditioning unit when there is a fault. Most commonly 1 of the normally closed relay switch contacts are in series with the compressor control circuit, a normally open set of contacts are wired into the relay coil and the coil is energised by HP, LP overloads in parallel. If a fault occurs the coil energises and the control circuit is broken stopping the compressor. By wiring a normally open set of contacts to the coil when the coil energises by a safety device it stays energised when the fault self resets. You have to power down the control circuit to reset the "lockout".

  8. #8
    Join Date
    May 2012
    Location
    Upper Michigan
    Posts
    3,589
    Quote Originally Posted by Core_d View Post
    Could you be more specific please.RIB?sub base?
    Sorry I was in the drive through and killing some time, is say mark got the point across thanks.

  9. #9
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
    Posts
    14,915
    Quote Originally Posted by syk35 View Post
    Maybe you are referring to what I know as a lockout relay?
    Yeap, that's another common use for them.
    If more government is the answer, then it's a really stupid question.

  10. #10
    Join Date
    Dec 2012
    Location
    columbus, OH
    Posts
    2,190
    Thanks for all the great responses. Any opinions on the term "isolation" used to describe the them? Is that even accurate? I noticed their was mention of an application for to different control voltages being used. Do these icecubes somehow isolate the different voltages or prevent feedback?

  11. #11
    Join Date
    Jan 2003
    Location
    Wa.
    Posts
    56
    Isolation relays are exactly what they imply. They either isolate different voltages through a given voltage signal to complete a process or they isolate a switching process of different voltages to give a result. In other words they isolate dis similar voltages to complete a task.

  12. #12
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
    Posts
    14,915
    Quote Originally Posted by Core_d View Post
    Thanks for all the great responses. Any opinions on the term "isolation" used to describe the them? Is that even accurate? I noticed their was mention of an application for to different control voltages being used. Do these icecubes somehow isolate the different voltages or prevent feedback?
    Yes, a common HVAC application would be a commercial system that has 230v contactor coils for the compressor(s) and fan motors, but 24v external controls, like the thermostat.
    Pressure switches, and other safety controls that are located outside of the units main control panel, are often part of the 24v control circuit too.
    Most of it is done with control boards these days, but you will find varying degrees of relay isolation and logic between the low voltage external controls, and high voltage internal controls, on older systems.

    Basically low voltage switches, controlling low voltage relays, that are switching high voltage relays, that are switching high voltage high current loads.
    If more government is the answer, then it's a really stupid question.

  13. #13
    Join Date
    Dec 2012
    Location
    columbus, OH
    Posts
    2,190
    Quote Originally Posted by mark beiser View Post
    Yes, a common HVAC application would be a commercial system that has 230v contactor coils for the compressor(s) and fan motors, but 24v external controls, like the thermostat.
    Pressure switches, and other safety controls that are located outside of the units main control panel, are often part of the 24v control circuit too.
    Most of it is done with control boards these days, but you will find varying degrees of relay isolation and logic between the low voltage external controls, and high voltage internal controls, on older systems.

    Basically low voltage switches, controlling low voltage relays, that are switching high voltage relays, that are switching high voltage high current loads.
    I guess that pretty well puts it in a nutshell or "box". I would entertain a comprehensive schematic or link if anyone has one handy. I did attempt to google this before i brought my query here.

Page 1 of 2 12 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event