20 S&C Instruction Sheet 681-510
Operation
Low-Voltage Phasing Using Optional
VOLTAGE indicator with Phasing
STEP 1.
Clean the surface and phasing pins of the
VOLTAGE indicator of dirt and debris. See
Figure 38.
STEP 2.
Test the VOLTAGE indicators for proper oper-
ation by following Step 3 under “Checking for
Voltage Using Optional Voltage Indica
tor”
section on page 17. If a VOLTAGE indica tor is not
operating properly, phasing should be
performed using an alternate method.
STEP 3.
Using a high-impedance voltmeter, verify
voltage is present and determine the phase-to-
ground voltage for each phase of the two ways
●
to be phased as follows:
(a) Set the voltmeter for volts ac. See Figure 39.
(b) Connect one of the test probes of the
voltmeter to the metal tank of the switchgear
to ground the voltmeter. See Figure 40.
(c) Place the other test probe on each of the
phasing pins, in turn, of the two ways to be
phased and measure the phase-to-ground
voltage. See Figure 38.
(d) If the voltage measured at each phasing pin
is greater than zero and they are equal,
proceed to Step 4 on page 21.
(e) If the voltage measured at any of the phasing
pins is zero, the phases are not energized and
phasing cannot be per formed. If the voltages
measured are not equal, the voltmeter may
not be operat ing properly. Phasing should be
performed using an alternate method.
●
A “way” consists of a three-phase load-interrupter switch, a three-
phase fault interrupter, a bus tap, or three sin gle-phase fault interrupters.
Connect probe to metal tank
Connect other probe to Phasing Pin
VOLTAGE Indicator
Phasing Pin 3
Phasing Pin 2
Phasing Pin 1
Figure 40. Ground the voltmeter.
Figure 38. Before performing phasing, thoroughly clean the
VOLTAGE indicator surface and phasing pins.
Set voltmeter to
volts ac
Voltmeter
Figure 39. Voltmeter for low-voltage phasing.
Probe
