Testing Thermal Overloads 2

[jlatta]

At the plant where I work, we periodically test some important thermal overload heaters in place (in the MCC). I want to make sure we're doing it right, so does anybody know if there are "standard" test methods with acceptance criteria that take into account the temperature difference between the MCC and the assumed 40°C ambient the overload heater curves are based on? These 480 vac MCCs are generally in a controlled environment with approximately 25°C ambient.

 

[mc5w]

I am glad that you found something that tells you how single phase single phase sensitivity works. Taking apart stuff to see how it works is very educational, sometimes the only way to get the data that you want. I recently had to do this to a failed General Electric ballast because General Electric does not have a clue as to how much inrush current I need to expect.

I should have told you to look in a printed (hard copy) Klockner-Moeller catalog.