JiGO NVAHZ-1P DIN Rail Meter

Fitting a voltmeter, an ammeter and a frequency meter means three modules, three sets of wiring and three places to look. The NVAHZ-1P puts all three in one DIN rail unit, which is both cheaper and easier to read, because the values that have to be interpreted together are presented together.

What it shows, and why that combination

• Voltage — the supply condition, and the first thing anyone checks on a fault call
• Current — what the circuit is actually drawing, which is how a developing problem shows itself
• Frequency — engine speed on a generator, output setting on an inverter or drive
• All three together — a generator low on volts and low on hertz is a loading problem; low volts at correct hertz is something else entirely, and only the combination tells you which

That last point is the real argument for a combined meter. On a DG set in particular, voltage and frequency read side by side distinguish an excitation problem from a governor or fuel problem in a couple of seconds.

Connection and selection

Confirm how the current input is to be connected when ordering — direct in line for small loads, or through a current transformer for larger ones. Tell us the circuit rating and we will specify it correctly and supply the CT if one is needed. The unit indicates only; for disconnection on an out-of-range condition, use an NP series protection relay.