Page 19 - EngineerIT January 2022

MEASUREMENT

As with any electrical system, the AC side, use the Fluke 393 FC to check the inverter’s output voltage and current
check for broken wires and any levels. Many of these systems have a display that indicates current inverter and
loose connections. Clean all dirty system performance. As the Fluke 393 FC produces a true-RMS reading, you can use
connections and replace all bad the voltage and current to measure and record the power output in kilowatt (kW).
wiring. With the power off, check for If possible, use the inverter display to show the current total energy in kilowatt
and repair any ground faults. If any hours (kWh) and compare it to the one recorded during the last inspection. When
fuses blow or breakers trip again, troubleshooting the DC side, use the Fluke 393 FC to check the DC power and save
there will be a short that will need to the reading to the Fluke Connect™ app on your phone.
be located and repaired. If the inverter does not produce the right amount of power, there may be a blown
If the load still does not operate fuse, tripped breaker or broken wires — all of which can easily be checked with the Fluke
properly, use the Fluke 393 FC to 393 FC.
check the system’s voltage at the
load’s connection. The wire size 4. Troubleshooting combiner boxes
may be too small and need to be When troubleshooting combiner boxes, amperage measurements and calculations are
increased. This will show up as a low crucial to establishing whether the PV arrays are operating correctly. Measuring current
voltage at the load and to resolve, on individual arrays or combining current measurements will help determine if a module
either reduce the load on the circuit has malfunctioned.
or run a larger wire. The thinner jaw design of the Fluke 393 FC clamp meter ensures that several
conductors are used in the jaw for combined current measurements, even in tight or
3. Troubleshooting PV inverters crowded spaces like inverter or combiner boxes. n
The inverter converts DC from
the PV system into AC power for Fluke is represented in South Africa by Comtest.
building use. For troubleshooting Visit www.comtest.co.za or call 010 595 1821

EngineerIT | January 2022 | 17