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Folks,

 

I am looking to purchase some PTC resettable breakers and I am not sure what some of the specs are saying.   They have both a "Hold" current and a "Trip" current.  I've read the description and I am still a little confused as to what it means.

 

For example, if I am looking to have the circuit open at 5 amp do I select the PTC with a trip current of 5 amp?   What is confusing me is that one of the members recommended a 5A PTC but in looking at the spec it says it has a 5A hold and 10A trip which tells me it will trip when the amps hit 10A.

  

What I am looking to accomplish is to use a PW ZW for both command and conventional and I want to be sure I have adequate quick acting breakers.

 

Thanks,

Ed

Original Post

After using them for many years, I use the smallest hold rating that will work for running.  On my mains where I run passenger trains (they use the most amps) I use PTCs with hold rating 8 or 9 amps and never trip from an overload.  Freight trains seldom use more than 5 amps so a hold rating of 5 amps is fine.

 

The beauty of the PTCs is they're cheap enough so you can test for the lowest hold rating for your conditions.  The closer you are to the correct hold rating the quicker a fault will trip the circuit.  Caution!  Do not touch the PTCs to see if they're working.  They run hot under a full load.

Post

OGR Publishing, Inc., 1310 Eastside Centre Ct, Suite 6, Mountain Home, AR 72653
800-980-OGRR (6477)
www.ogaugerr.com

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