When thermal relay test fail 1

[parlitu]

Supose I test a thermal relay (bimetalic) using current injection-2*setting current(Is) and the tripping time is not correct. Let say is bigger. What will be the write action?
1. Adjust the setting current of thermal relay at a smaller value-Iss and inject again 2*setting current(Is). The tripping time should be less, and the relay can be consider calibrated when this time will meet the curve for 2*Is; after every test will be a brake of 10-20 minutes to cooldown the bimetalic relay
2. Replace the termal relay

 

[oldfieldguy]

2 x setting current is lower than I typically tested them. The acceptable error band is larger, and a small change in test current will make matters worse.

We used to typically test these things at 300% full load current. Manufacturers weren't really specific about tolerance.

I'd replace the relay. Also, remember that too many subsequent tests will cause deterioration of heater elements.

old field guy