Low Frequency Operating In Transformer Coupled Mode; Table 4-1: Programmable Impedance Ranges By Phase Mode - Pacific Power Source LMX Series Operation Manual

Models

4.5 Low Frequency Operating in Transformer Coupled Mode

LMX-Series output transformers are designed to operate from 45 to 5,000 Hz. In the case of
steady-state sine wave output, operation at frequencies as low as 30 Hz (125 Vac primary
voltage) is possible.
Operation at lower frequencies - below 30Hz - may cause saturation of the output
transformers, but at reduced output voltages, lower frequency operation is possible. The
Volt*Second Product of the output MUST NOT exceed the maximum Volt*Second rating of
the transformer to prevent saturation of the transformers when operating at lower
frequencies.
For example, to determine the value of reduced voltage at 20Hz operation of the
transformer described above:
1. Calculate the VoltSecond Product maximum value of the transformer at 30Hz and 125
Vac
T
30 Hz
Calculate the reduced output voltage value at 20Hz with maximum Volt Second Product
value
T
20 Hz
Therefore, to prevent output transformer saturation at 20Hz operation, the maximum
primary voltage of the transformer should be 82.5Vac.
Systems with transformers connected to the output require special attention when
designing transient profiles (applicable to systems w/UPC). It is possible to design transients
in which the DC Component of the periodic waveform is not zero. Attempting to push DC
voltage through the transformer will cause saturation of the transformer. However, the
output transformers are designed to support a single event, half-cycle dropout at 125 Vac
primary voltage at 50 Hz without saturating. Continuous operation with an asymmetrical
waveform (DC component ≠ 0 Vdc) will cause saturation however.
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Entire Contents Copyright 2018 by Pacific Power Source, Inc. (PPS) • All Rights Reserved • No reproduction without written authorization from PPS.
LMX Series Power Source Operation Manual
Phase Mode Real Time R
Single Phase

Table 4-1: Programmable Impedance Ranges by Phase mode

1 1
= = =
. 0 033 sec
Freq 30 Hz
1 1
= = =
. 0 050 sec
Freq 20 Hz
LMX SERIES® OPERATION MANUAL
± Limits 0 - Max Limits
Real Time L +
+/- Ohms
µH
20.000 10.000
• =
Volt Sec T
max 30 Hz
•
Volt Sec
=
max
Volts
T
20 Hz
SECTION 4: Technical Specifications
± Limits 0 - Max Limits
RMS R +/-
RMS L + µH
Ohms
20.000 10.000
× = × =
V . 0 033 125 . 4 125 volt
rms
•
. 4 125 volt sec
= =
82 5 . volts
. 0 050 sec
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•
sec