Application Note

3 Fluke Corporation Inrush current
The right tool for the job
New high efficiency motors
require better tools to evalu-
ate and fix the consequences of
their high inrush current. The
Fluke 370 Series of clamp meters
is designed to capture inrush
current accurately and, most
importantly, synchronously, pro-
viding readings that accurately
depict what the circuit protector
experiences.
Using the right tool for the job
allows you to protect your plant’s
equipment investment and avoid
some of the annoying problems
inherent with installing new
motors.
Additional resources
Fluke Corporation
www.fluke.com
IEEE
www.ieee.org
Glossary of terms
a to d converter
Analog to digital converter. An electronic hardware device that
converts analog signals to digital signals.
Analog peak
The highest peak value measured that lasted some specified time
period, usually measured in milliseconds.
Circuit breaker
An electrical device configured to supply overload and short circuit
protection to an electrical circuit. They range in complexity from
the common and simple thermal overload/magnetic trip devices
to complex electronic units that allow the adjusting of several trip
parameters.
Digital min/max
The measurement of the minimum and maximum values (e.g.,
voltage, current or resistance) over a specific period of time.
Inrush current
A transient condition, generally lasting 100 milliseconds or more
that occurs during motor start-up.
Overload units
Devices in motor start control units, such as heater coils, overload
trips, thermals, etc. that protect the motor while its running. There
are a number of different phrases used worldwide to refer to
these devices.
Fluke Corporation
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©2001-2012 Fluke Corporation.
Specifications subject to change without notice.
Printed in U.S.A. 7/2012 1629920B_EN
Modification of this document is not permitted
without written permission from Fluke Corporation.
Fluke. The Most Trusted Tools
in the World.