JiGO NHz-1P Frequency Meter

Frequency is the one supply parameter nobody measures until it matters, and then it matters a great deal. On a mains supply it barely moves; on a generator it is the direct indication of engine speed and loading, and on an inverter or a variable frequency drive it is the output being commanded.

Where a frequency meter earns its place

• Generator sets — frequency is engine speed. A DG drifting from 50 Hz under load is telling you about the governor, the fuel system or the loading long before anything trips
• Inverters and UPS — confirming the output frequency is what it should be, and that the unit has not fallen back to bypass
• Changeover verification — checking a standby source is at the right frequency before it takes the load
• Variable frequency drives — a local indication of output frequency at the panel

One module wide, it clips onto the DIN rail beside the breakers it is monitoring. Used with the matching NV-1P voltmeter and NA-1P ammeter, three modules give voltage, current and frequency on a single row without a panel-door cut-out.

Connection and selection

The NHz-1P is an indicating instrument. It measures and displays; it does not switch, protect or log. Where the supply must be disconnected on an out-of-range condition, use a protection relay from the NP series instead.