Harmonics Solutions; System Monitoring; Power Monitor Panel - Emerson Liebert PPC 15-30 kVA Technical Data Manual

H S
ARMONICS OLUTIONS
Solutions to Harmonics Problems
Precision Power Centers are available with several
harmonic solution options, along with the standard
product features, to provide flexible power distribu-
tion for today's nonlinear loads.
The basic Precision Power Center is designed to
accommodate moderate levels of harmonic currents.
All Precision Power Center isolation transformers
provide cancellation of the load triplen harmonic cur-
rents and are designed to tolerate neutral currents
up to 1.73 times full load. When severe levels of har-
monic currents are anticipated, several additional
power center features are available.
Features Comparison
Designed for nonlinear loads
Neutral sized for greater than 1.73X FLA
Available with multiple outputs for mainframe computers
Reduces harmonic current distortion
Improves harmonic power factor
Cancels triplen (3rd, 9th, 15th, etc.) harmonics
Tolerates higher levels of harmonic currents
Cancels non-triplen (5th, 7th, etc.) harmonics
S M
YSTEM ONITORING
Monitoring systems for Liebert power conditioners range from temperature sensing to multiple-parameter
monitoring with remote display and printout.
All units are equipped with a guarded and illuminated Local Emergency Power Off switch; provisions for con-
necting Remote Emergency Power Off switch; selectable auto or manual restart feature, to allow an orderly
system restart after a power failure; a summary alarm contact; and a building interface relay.
K-Factor Transformers
Shielded isolation transformers with a K-20 rating
are specially designed to minimize the heating
effects of the load's harmonic currents and to tolerate
full harmonic loading without overheating.
Multi-Winding Transformers
Shielded isolation transformers with multiple sec-
ondary windings that are phase shifted provide can-
cellation of the load's non-triplen harmonic currents.
With K-Factor
Basic System Transformer
X X
X X
X X
X X
X X
X X
X

Power Monitor Panel

True RMS techniques are used to provide accurate
measurements of Precision Power Center operation,
while the high visibility Liquid Crystal Display pro-
vides clear reporting. The microprocessor-based
power monitoring system continuously monitors and
sequentially displays the following parameters:
• Input voltages, line-to-line for each phase
• Output voltages, line-to-line and line-to-neutral
for each phase
• Output currents for each phase, including neutral
and ground currents
• Output voltage THD for each phase
• Output current THD, K-factor and crest factor for
each phase
• Output power including kVA, KW, KW-hours,
power factor, percent load and output frequency
8

Harmonics Solutions

With Multi-Winding
Transformer
X
X
X
X
X
X
X
X