Valhalla 2300, Operation Manual

Page: 27 / 115

SECTION VI MANUAL OPERATION
_______________________________________________________________
6-1. General
The following paragraphs describe the manual
operation of the 2300 series power analyzers
and should be used along with Sections 4 and
5 for complete operating instructions. The
user is advised to fully read these sections
before attempting to operate the 2300.
Section 7 describes operation via the IEEE-
488 interface.
6-2. Safety Precautions
CAUTION!!
IN NORMAL USE THE TERMINALS OF
THE 2300 ARE CONNECTED TO LETHAL
VOLTAGES. DEATH MAY OCCUR ON
CONTACT!
Do not attach or remove wires without first
checking that all power sources have been
disabled. Do not open-circuit the secondary
windings of current transformers when they
are energized. Lethal potentials may exist
which can damage the transformer, the 2300,
and the operator.
6-3. Operation
The 2300 contains three independent
wattmeter channels (phases). Single-phase
power may be measured using any of the
three channels. Three simultaneous,
independent, single-phase measurements may
also be made.
When measuring three-phase power, the
number of leads connected to the load
determines how the 2300 is connected. If the
load has three-wires, the two-wattmeter
method is used to measure the total power.
The total power is the sum of the two
wattmeter readings. Phase B is
used as the reference (neutral) for
the other channels. Wattmeter channel A
measures the current in phase A and the
voltage between phase A and phase B.
Channel C measures the current in phase C
and the voltage between phase C and phase B.
Phase B is not used other than as a reference.
The 2300 sums the phase A and C power
readings when the 3
φ
3-WIRE mode is
selected. The voltage and current displays are
blanked in this mode as they are invalid. The
individual line currents, line to line voltages
and phase powers can be displayed by
pressing the
φ
A or
φ
C push-buttons. A
complete proof of the validity of the two
wattmeter method is beyond the scope of this
manual, and may be found in a college level
electrical engineering textbook.
If the load has four-wires, all three wattmeters
must be used to measure the total power. The
total power is the sum of the three wattmeter
readings. Channel A measures the current in
phase A and the voltage between phase A and
neutral. Channels B and C similarly measure
phases B and C. The 2300 sums the phase A,
B, and C readings when the 3
φ
4-WIRE mode
is selected. The voltage and current displays
are blanked in this mode as they are invalid.
The individual line voltages, currents, and
powers may be displayed by pressing the
φ
A,
φ
B, or
φ
C display selection push-buttons.
6-4. Connections
The 2300 has a separate cluster of terminals
for each of the three phases. Each channel has
three current terminals, with use determined
by the amount of current to be measured. The
three current terminals are internally
connected to the 1 ampere, 10 ampere, or 100
ampere shunts. The opposite ends of the three