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TECHNICAL TRAINING

DID YOU FLUKE IT?

By Donald Dougherty, Senior Technician

“Yeah, we fluked it!”

The Fluke-meter, or Digital Multi-Meter is one of the most highly
used and versatile tools for troubleshooting electrical and electronic control
systems.

Multi-meters measure a variety of electrical values such as volts, ohms,
and amps. The most common use on LORAM machines is checking for the pres-
ence of AC voltages and checking shorted/bad grinding motors. In this article
we’ll discuss how to get the most out of this essential tool.
First, it is highly recommended that you use ARC Flash PPE when checking any voltages above 24Volts,
and ARC Flash PPE is absolutely required when checking for the presence of 480 Volts. Another safety and con-
venience recommendation is to use an alligator clip on the common lead and a magnetic meter hanger while tak-
ing readings. This makes using the meter easier and safer by freeing up hands you would otherwise use to hold
the meter, the common (black) lead, and the red lead. That’s a lot to concentrate on! The alligator clip can be of
particular help when checking multiple DC voltages, because a solid reference is important to get consistent read-
ings. A final note: The meter should be well cared for. Like any other tool, it needs be inspected prior to use, es-
pecially the leads. Be on the lookout for broken insulation particularly near the probes. Also, it is important to
keep the entire unit clean.

Pictured on the following page is an example of a fluke multimeter. The main center “dial” is used to se-
lect the type of reading you wish to take. In most cases you will be looking for specific values such as 10, 12, and
24volts DC, 120, 277, or 480volts AC.

When switched on initially, the meter is in the Auto Range mode. While handy, the auto range mode
sometimes can display erroneous readings that are hard to interpret. The best bet is to use the Range Key to ad-
vance the decimal point so that there is just one digit to the right as shown on the meter below. Typical readings
do not require accuracy beyond one tenth of a volt/unit unless you are calibrating very sensitive components.

Just be sure you are reading Volts, not milli-Volts and Ohms not Mega-Ohms during measurement.

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