Pacific UPC-12, Operation Manual

Page: 20 / 140

SECTION 2 SPECIFICATIONS
8
2.1.2 VOLTAGE CONTROL SPECIFICATIONS
The voltage amplitude of each vector can be varied independently.
There are two output coupling modes selectable in the stored programs of the UPC.
1) DIRECT COUPLED MODE:
Range: 0 to 150 VAC rms
Resolution: 0.1 volts
Output Ratio: 1.0 (This mode is internally fixed)
2) TRANSFORMER COUPLED MODE:
Range: 0 to (150 x XFMR RATIO) VAC rms (maximum of 600 volts)
Resolution: dependant upon the TRANSFORMER RATIO as described below.
This allows for a possible output voltage of up to 375 VAC rms line-
neutral, using an output TRANSFORMER RATIO of 2.5.
The voltage range available at any given time is automatically calculated by the UPC and accounts for
the set Transformer Ratio. The power source will be driven with the correct amplitude signal and does
NOT require the user to perform any calculations to determine output voltage dependant upon the
transformer ratio.
The UPC allows the Power Source to use any output TRANSFORMER RATIO from 0.01 to 5.11.
Voltage resolution for TRANSFORMER COUPLED MODE is as follows:
XFMR RATIO Vresolution
.01 - 1.00 0.1 VAC rms
1.01 - 5.11 0.5 VAC rms
The default ratio is set by the TRANSFORMER RATIO SWITCH on the UPC METERING PCB. See
section 3.4.1. The default value may be overridden by entering a new value in the UPC STATUS screen
and in the program to be executed. The power source must have an output transformer configured with
the same ratio as presently set for this feature to work properly.
TRANSFORMER RATIOs greater than 1.0 are step-up types.
TRANSFORMER RATIOs less than 1.0 are step-down types.
Accuracy is ± 0.5% of full scale over the range of ambient conditions with CSC disabled.
Accuracy is ± 0.05% of the voltage referenced to the internal voltmeter with CSC enabled.
NOTE : TRANSFORMER RATIOs are implied as a ratio to one, e.g.; a ratio of 2.5 is implied as a ratio of
2.5:1.
NOTE : The above voltages are power source output voltages. The UPC actually produces an RMS
voltage equal to (Power source output Vrms / 25 / TRANSFORMER RATIO). The SCU provides this
type of low voltage output at the rear panel connector, to be fed into a power source.
A unique feature available within the UPC is TRANSITION TIME. If Transition time is set to a non-zero
value, and a new program is executed, or changes are made in MANUAL MODE (or by REMOTE
CONTROL), the UPC will take the specified time to transition from the active voltage and frequency to
the new voltages and frequency. This feature may be used when it is undesirable to cause abrupt
changes to the output power signal. This feature does not affect transient operation. Transition time may
be set from 0 to 300 seconds in increments as small as 200 uS.