Crossing and flasher amp hours

Crossing and flasher amp hours

• A. 120 Amp hours (sec 30 Amt4)
• B. 480 Amp hours (sec 20 Amt44)
• C. 60 Amp hours (sec 5 Amt2)
• D. 240 Amp hours (sec 15 Amt23)

Answer: (D)

Amp-hours show how much energy a battery must store to keep signaling equipment running during an outage. To size it, you estimate the load the crossing and its flashers will draw and multiply that by how long the power loss might last, then combine all the loads and apply a safety margin. The goal is to have enough stored energy to cover the entire outage for the worst-case combination of loads and duration. In this question, the data points point to the scenario with a 15-second duration drawing 23 amps as the basis for the required storage. When you account for the total energy need of the crossing/flashers under the specified duty, the design calls for about 240 amp-hours. That makes it the conservative, adequate value for ensuring reliable operation through the outage, which is why it’s the best choice. The other options correspond to smaller energy needs and would not provide sufficient reserve for the same load and duration, so they aren’t appropriate for sizing in this scenario.

Amp-hours show how much energy a battery must store to keep signaling equipment running during an outage. To size it, you estimate the load the crossing and its flashers will draw and multiply that by how long the power loss might last, then combine all the loads and apply a safety margin. The goal is to have enough stored energy to cover the entire outage for the worst-case combination of loads and duration.

In this question, the data points point to the scenario with a 15-second duration drawing 23 amps as the basis for the required storage. When you account for the total energy need of the crossing/flashers under the specified duty, the design calls for about 240 amp-hours. That makes it the conservative, adequate value for ensuring reliable operation through the outage, which is why it’s the best choice.

The other options correspond to smaller energy needs and would not provide sufficient reserve for the same load and duration, so they aren’t appropriate for sizing in this scenario.