Frequently asked questions
Video: Can you read trip history from the LCD screen on the Micrologic A (Ammeter) trip units? 2.0A, 3.0A, 5.0A, and 6.0A
28 September 2021Product Line:
Micrologic A (Ammeter) Trip Units 2.0A, 3.0A, 5.0A and 6.0A
No, the Micrologic A (Ammeter) trip units do not store trip history. For that you need a Micrologic P (Power) or H (Harmonic) trip unit. (see document 48049-136-05 for complete information).
While the A trip unit does not have trip history, it does capture the peak current that has flowed through the breaker. That can be seen on the trip unit in the "Peak Menu". To access the information, press the "menu" button on the trip unit (trip unit screen must be powered). The first time the menu button is pressed, the screen displays the "Current Menu". Repeated pressing of the menu button cycles the screens in the following order:
-Trip Unit Settings
Following are the details:
The Current Menu displays the real-time amount of current flowing through the breaker for each phase (IA, IB, IC), plus any ground-fault current (Ig). For 4-pole breakers, it also shows the amount of neutral current (In). Neutral current is not displayed for 3-pole breakers.
The Peak Menu displays the maximum (peak) current that has flowed through the breaker for each phase (IpA, IpB, IpC), plus the maximum ground-fault current (Ipg). For 4-pole breakers, it also shows the maximum neutral current (Ipn). Neutral current is not displayed for 3-pole breakers. Note that the peak current is not necessarily the same as the trip current. In other words, a breaker that has never tripped will still show a peak current. Also, the peak current values remain stored in the trip unit even if it is removed from the breaker. To reset those peak values, scroll to each of the values to be reset, then press and hold the scroll button for 3 seconds.
Trip Unit Settings
The Trip Unit Settings are the ampere pickup values and the time delay values, based on the combination of the trip unit dial settings and the breaker in which the trip unit is installed. The values include Long-Time Pickup (Ir) and Delay (tr), Short-time Pickup (Isd) and Delay (tsd), Instantaneous Pickup (Ii), and Ground-Fault Pickup (Ig) and Delay (tg). Note that if the trip unit is removed from the breaker and connected to 24Vdc power supply, the values default to Ir of 100A. These reset once the trip unit is re-installed in a breaker. Not all trip unit have all the following settings, check the trip unit itself for applicable values.