What would indicate a malfunction on a GMDSS station with a 24 VDC battery system?

• A. A constant 30 volt reading on the GMDSS console voltmeter
• B. A fluctuating voltage between 22 and 28 volts
• C. A steady 24 volt reading
• D. A reading of 15 volts

Answer: (A)

In a 24 V DC GMDSS power system, the voltage that feeds the equipment should stay close to the nominal 24 volts. If the voltmeter shows a constant reading well above that, it points to an overvoltage fault in the power supply or charging circuit. A steady 30 volts means the regulator or charger isn’t regulating properly, which can stress or damage GMDSS equipment and may trip protective circuits.

By contrast, a steady 24 volts is normal and indicates healthy operation. A reading of 15 volts shows undervoltage, which can cause equipment to malfunction or shut down. A fluctuating range like 22 to 28 volts could occur during charging or load changes, but the persistent, excessive 30-volt reading is the clearest sign of a malfunction.