Hello,
I am working in a facility that has older bkrs, West HKL & HLM type. From what I have been able to determine these bkrs have trip units that can be changed to change trip, for example a 400A Frame bkr can have a 400A trip or 225A trip. One can see what the trip unit is from a cutout on the breaker. What I can not locate is what the instantaneous setting is? It appears that it may be on the interchangeable trip unit which is only accessible by taking the breaker cover off.

does anyone have any experience with these breakers? I have also not been able to find a manual on the trip units themselves.

Thank you in advance.

A little experience. Chances are that they are way out of calibration. My old (1980's) catalog lists two generations of replacements. Even if I had data (probably originally intended for 6x or 10x trip), I would not even consider trusting them without testing. The Eaton/Cutler Hammer ones are drop in replacements with the same bolt patterns, lugs, and so forth, if you wanted to spend about the same amount of money replacing them. The last time I had to deal with these, I found that 60% had to be replaced either because they did not trip at all anymore or were grossly out of calibration. The money spent on testing was basically more of an exercise to prove that they were no longer safe to operate.

Go with Paul's recommendation. Have had two major plant breaker testing projects, (150 & 300 breakers tested) this year. All the breakers were the same vintage as or were the same Westinghouse units in question.
78% of the units failed to trip or did not trip within the trip curve times.

With both clients, embarking on a "major" electrical distribution system upgrade.

I have the time current curve. It shows that the instantaneous setting is adjustable up to 10 times the trip rating. Let me know if you need anything else.

Robert,
Thank you but I do have the curve. My question was where is the adjustment for the instantaneous setting as there is nothing visible on the breaker. Does the breaker cover need to be removed to access the trip units instantaneous setting?

Look at the top of the curve, it say "adjustable".

Yes, I know that. Please pay close attention to my question. On the physical breaker itself, there is no visible adjustment for instantaneous trip. Many breakers have this feature assessable on the front of the breaker. This type of breaker appears to require that the breaker be dis-assembled to access the instantaneous trip adjustment on the interchangeable trip unit. I am just trying to confirm this with someone that has experience with these breakers.

Its behind a door on the front. Just a couple screws and you are in.

That is assuming you have an adjustable trip unit. It has been a while but one nice/annoying thing about Westinghouse is they always had options for everything. I never saw one but they might have had fixed units in that series. I know I ran into a lot of strange variations with their Digitrip units, because they were only semi-programmable.

That is assuming you have an adjustable trip unit. It has been a while but one nice/annoying thing about Westinghouse is they always had options for everything. I never saw one but they might have had fixed units in that series. I know I ran into a lot of strange variations with their Digitrip units, because they were only semi-programmable.

A liitle info - that bkr has an adjustable instantaneous. A breaker is not defined as adjustable trip unless the long time is adjustable

The definition for Circuit Breaker - Adjustable from NFPA 70 (NEC) is " A qualifying term indicating that the circuit breaker can be set to trip at various values of current, time, or both, within a predetermined range."
I don't see that as limiting the adjustable qualifier to be restricted to only a breaker that has LT adjustable.