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Applications
Load studies
Discover how much energy individual pieces of
equipment are consuming when they are operat-
ing at minimum and maximum capacity. Check
capacity of circuits prior to adding additional
loads (various standards exist for this process;
in the US the NEC 220-87 is the recommended
standard). Load studies can also identify situations
where you may be exceeding the allowable load
on the circuit or when an agreed peak demand
applies from the utility. For convenience, some
load studies simply measure current which makes
installation of the measuring equipment quick and
easy. It is often recommended that load surveys
be performed for 30 days so that all typical load
conditions are encountered during the test.
Energy surveys
Users often ask where measurements should be
taken for an energy survey. The answer is mul-
tiple points within the facility. Start at the main
service feeders; compare the power and energy
measured here with the readings from the util-
ity meter to ensure you're receiving the correct
charges. Then move downstream to the larger
loads; these should be easy to identify by the cur-
rent rating of the electrical panels downstream of
the service entrances. Measuring at many points
will allow a full picture of energy usage across
the facility to be developed. The next ques-
tion users typically have is how long an energy
survey should last. This of course depends on the
facility, but it is recommended that you measure
for a period that matches a typical facility activ-
ity period. If the facility operates over a five day
work week with down time on the weekend, a
seven day survey will most likely capture typical
conditions. If the facility operates at a constant
level for 24 hours a day, 365 days a year, a single
day could be reasonably representative as long as
you avoid a period where there may be planned
maintenance.
To capture a full picture of the facilities energy
usage it is not necessarily required to have
measurements made simultaneously at every
consumption point in the facility. To get a compre-
hensive picture, spot measurements can be made
and then compared on a sliding time timescale.
For example, you could compare the service
entrance results from a typical Tuesday between
6:00 am and 12:00 pm with those of a larger load
in the facility. Typically there will be some cor-
relation between these profiles.
2 Fluke Corporation
Fluke 1730 Three-Phase Electrical Energy Logger
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Power and energy logging
When a piece of equipment is operated it instan-
taneously consumes a specific amount of power in
watts (W) or kilowatts (kW). This power is accu-
mulated over the operating time and expressed as
energy consumed in kilowatt hours (kWh). Energy
is what your electric utility charges for; there will
be a standard charge from the utility per kilowatt
hour. Utilities may have other additional charges,
such as peak demand, which is the maximum
power demand over a defined period of time,
often 15 or 30 minutes. There may also be power
factor charges, which are based on the effects of
the inductive or capacitive loads in the facility.
Optimizing peak demand and power factor often
results in lower monthly electricity bills. The
1730 Three Phase Electrical Energy logger has
the capability to measure and characterize these
effects enabling you to analyze the results and
save money.
Simplified load studies
For situations where it's either difficult or imprac-
tical to make a voltage connection the simple load
study feature allows users to perform a simplified
load study by measuring current only. The user
can enter the nominal expected voltage to create
a simulated power study. For accurate power
and energy studies it is required to monitor both
voltage and current but this simplified method is
useful in certain circumstances.
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