Emerson Exchange 365

CHARMS and Relay Output terminals for use in MCC applications

We're contemplating the use of CHARM's 24V High Side DO with relay terminals to switch 110VAC control circuits, this as an alternative to the traditional interposing relay panels typically found in DCS/MCC interfaces.  It seems like the hardware will support what we need, 5A rated contacts and support for 110VAC, but has anyone got an actual case study for using them in an MCC application?

Any gotchas for running high current applications or horror stories for replaceing relays etc.?

Cheers

• DeltaV 11.3
• CHARMS
• mcc
• motor control

AdrianOffield

6 Replies

• Niklas Flykt

  

  Hi,
  did you intend to switch motors directly or similar inductive loads?
  Do you have some schematics so we could see what your looking ?

  Niklas Flykt 

  Klinkmann Oy
  

  Key Account Manager safety products

  nikfly@gmail.com
• Niklas Flykt

  

  In reply to Niklas Flykt:

  Hi,

  tried to find the AC load ratings (Utilization categories) for the relay terminal but couldn´t.

  Maybe some other memeber of this community could supply them..? 

  Niklas Flykt 

  Klinkmann Oy
  

  Key Account Manager safety products

  nikfly@gmail.com
• AdrianOffield

  

  In reply to Niklas Flykt:

  Hi Niklas,

  It's a simple 480V Starter with 110V control circuit, see attached proposed schematic change.  The IRP panel will be the CHARMs DO Relay.

  
• Niklas Flykt

  

  In reply to AdrianOffield:

  Hi Adrian,
  looks good, I can´t see any problems using the CHARMs here.
  Is this an old installation were you are adding this control circuit?
  
  just some toughts...
  Here in Europe (north) we usually do not mix 24 vdc and 110 VAC control circuits.
  In your circuit you have the inputs 24vdc and outputs 110 vac, and the 24vdc and 110 vdc are beside each other in the plug.
  You don´t have to make too much mistake measuring the plug and you will get "burned fingers"

  Niklas Flykt 

  Klinkmann Oy
  

  Key Account Manager safety products

  nikfly@gmail.com
• AdrianOffield

  

  In reply to Niklas Flykt:

  It's a retrofit to an existing installation, and the voltage segregation should be followed here also, it is a schematic so it does not represent a true connection but it is certainly something I will check on with the vendor.
  
  In total I've got about 150 motor circuits across two substations (60/40 split) so about 90/60 charms in each. Looks like CHARMs is the way to go then.
  
  I'll update with results.
• Rachelle McWright

  

  In reply to Niklas Flykt:

  Here to help, thanks for the call out Niklas Flykt. Would it be helpful to have these ratings AdrianOffield ?

  Best Regards,

  Rachelle McWright: Business Development Manager, Dynamic Simulation: U.S. Gulf Coast