4
Description
same in either case. This external connection may be
useful when the incoming power is of poor quality so as
to affect the phase control circuitry of the test set. The
EXTERNAL position is also used to check the internal
am-meter calibration.
4.
Stop/Alarm Reset. This is a momentary push button that
is used to turn off the current source of the test set when
the trip device under test has not tripped. The switch
stops the operation of the internal stop-clock and drops
out the power control relay. The circuit is reset by
pressing the reset push-button. The STOP button also
resets the internal overcurrent and ground fault circuitry.
Following an overcurrent trip, there is a delay before
resetting will be successful.
5.
Alarm Light. This is a light emitting diode that is turned on
when either the overcurrent or the ground fault interrupt
circuit operates. This circuit is reset by pressing the
STOP push button.
6.
Pick-Up Lights. These light emitting diodes connect
directly to the test leads that attach to the trip device
under test. When the external leads are properly con-
nected the proper lights will be turned ON to indicate that
the trip device has picked up. Three lights are provided;
one for LONG TIME PICK-UP indicating that the long
time circuit of the trip device has been released and the
time delay circuit can operate, one for SHORT-TIME
PICK-UP indicating that the short time circuit of the trip
device is activated, and one for GROUND PICK-UP
which indicates that the trip device ground circuit has
been activated. Not all of the lights are used in all cases.
For example, if the device under test has no ground
circuit, the ground light is not used.
7.
Range Switch. When in the LOW position, this switch
inserts an additional current limiting air core reactor in
series with the device under test. It also sets the internal
am-meter to its LOW range. In its HIGH position the
additional reactor is removed from the circuit and the
internal ammeter is set to its HIGH range.
8.
RMS/Peak Responding Switch. This switch selects
response of internal ammeter (STATIC TRIP Ill/all other
tests).
9.
Static Trip Test/Actuator Test Selector Switch. When
this switch is in the STATIC TRIP TEST position, the test
current is supplied to the appropriate terminals of the
device under test. In this position the internal VOLTME-
TER is isolated from the rest of the internal circuitry and
the voltage applied to the DVM input terminals will be
indicated by the voltmeter. When this switch is in the
ACTUATOR TEST position the device current control
circuit is connected to the primary winding of a small
transformer/rectifier combination. The output of this
small DC power supply is connected to the DVM INPUT
ACTUATOR TEST OUTPUT terminals, and the voltmeter
indicates the voltage supplied by these terminals.
10. Seven Point Terminal Block. This terminal block is for
convenience in bench testing STATIC TRIP II trip de-
vices. The device fanning strip connects to the terminal
block on the test set. The terminals are prewired so only
the connections for pick-up indication are required.
11. Eight Point Terminal Block. This terminal block is for
convenience in bench testing STATIC TRIP 111 trip
devices. The terminal block is prewired internally so only
the device fanning strip need be connected.
12. Dual Response Ammeter. When peak responding (all
other tests) is selected the digital ammeter is con-
structed to respond to the peak value of the AC current
with the scale reading in amperes RMS. The ammeter is
calibrated with sinusoidal waveshape current. For other
than sine waves, the ammeter indication is the RMS
value for a sine wave with the same peak magnitude. In
this way the ammeter approximates the response of the
STATIC TRIP devices. When RMS (STATIC TRIP 111
LONG TIME) is selected the reading is in RMS, to match
the response of STATIC TRIP 111 devices long time
circuits. See Item 8 for selector switch, marked STATIC
TRIP 111 LONG TIME. Peak Responding is marked “All
other Tests.”
13. Electronic Stop-Clock. The stop clock indicates the time
duration that current was supplied to the device under
test. The time indicated is from initiation of current until
the trip device operates a relay internal to the test set and
includes the pick-up time of the internal relay which is
about 5 to 10 milliseconds. For trip device testing this
slight error can be safely ignored. Note that time values
are always slightly longer than the actual operating time
of the trip device.
14. Voltmeter. This is a digital meter circuit connected to the
DVM INPUT/ACTUATOR TEST TERMINALS. The meter
indicates 0 to 99 volts DC. (See Item 9 for operation of
the selector, switch). The voltmeter is not usable exter-
nally when the internal power supply is connected to its
terminals.
15. External Power Input Terminals. These terminals are
used to inject current from an external variable trans-
former when this method of testing is used.
16. Internal Power Control. This is a five turn potentiometer
that controls the internal phase controlled current source.
This control is also used to adjust the voltage when the
test set is used for testing the magnetic actuator of the
circuit breaker.
17. Start Switch. This switch closes the relays in the test set
to start current to the trip device under test. The relays
latch themselves in and current is stopped when the trip
