SVERKER 750/780
Relay Test Sets
PSS750
Phase selector switch PSS750
The Phase Selector Switch PSS750 is specifically designed to work
with SVERKER 750/780 when testing three-phase relays. It is
connected between SVERKER 750/780 and the relay inputs and
allows the user to easily select which phase to test.
The PSS750 handles both the current and voltage sources and
single-phase or phase-phase testing can be selected. Together
with the output-input switching the unit also contains a variable
resistor that can be used together with the built-in capacitor in
SVERKER 750/780. This feature gives the user the possibility to
create a variable phase shift at a decreased amplitude of the test
voltage.
The design is passive which makes it very general. You may for
example use any of the inputs for current or voltage as long as you
do not exceed the specification. It is also possible to connect the
measuring inputs of the SVERKER 750/780 to the PSS750 and
use the switch for selecting measurement signals.
The PSS750 simplifies phase switching, selecting type of fault,
phase reversing and gives a possibility to create a variable phase
shift..
Specifications PSS750
Specifications are valid at nominal input voltage and an ambient
temperature of +25°C, (77°F). Specifications are subject to
change without notice.
Max input voltage
250 V AC / 3 A
Max input current
6 A / 250 V AC
Max resistor loading
200 V AC / 200 mA (0.5 A during
5 seconds)
Dimensions
200 x 120 x 85 mm
(7.9” x 4.7” x 3.3”)
Weight
1.3 kg (2.9 lbs)
Application example with PSS750
IMPORTANT!
Read the User’s manual before using the instrument
1. Connect the current and voltage outputs of
SVERKER 750/780 to the PSS750 inputs.
2. Connect the current and voltage inputs of the relay to the
PSS750 outputs.
3. Select which phase to test and type of test (phase-to-ground or
phase-phase) with the selector switch.
4. Proceed with the test for each phase and fault type.
5. To create a phase shift, connect the 10 µF capacitor in
SVERKER 750/780 in series between the voltage output and
the PSS750 input, and connect the variable resistor in parallel
with the PSS750 input.
6. Set the SVERKER 750/780 for phase (and impedance) mea-
surement. Connect the voltage measurement input to the
PSS750 input.
7. Start the test with the resistor in maximum position. Gradu-
ally decreasing the resistor gives increasing phase shift in the
voltage signal. The test voltage/impedance will decrease at the
same time so an adjustment of the test current might be neces-
sary to get the correct impedance. Please observe that the phase
shift depends on the input resistance and may vary between
different relays. Some relays may also have a low voltage lim-
it where the relay will not operate. For additional 180 degrees
phase shift use the phase reversal switch.
