Operation; Warnings; Cautions; Preliminary Procedure - Foster SCITS100 Instrucciones De Uso

Operation

Warnings

1. Ensure that the Current Injection Test Set is properly earthed (grounded) before use, either through the mains
supply cord or the separate earth terminal on the control panel.
2. Ensure that all output terminals are clean and free of dirt and grease, prior to switching on. Remember that the
SCITS100 has an 1800 VA rated transformer and is therefore capable of dangerous outputs.
3. Only leads rated at 100 A or greater should be used with the instrument. Suitable output leads are available as
an optional extra.
4. Prior to switching on the mains supply to the instrument, ensure that both output controls are turned fully
anti-clockwise and the 'Set/Test' switch is in the '0' (off) position.
5. Never leave the instrument in the 'Set' position for longer than is necessary to set-up the appropriate output, as
this may severely damage the relay under test.
6. The separate 120 V a.c. output terminals have a zero voltage interlock, and are independent of the main output
control and interlock.
Ensure that the auxiliary output control is turned fully anti-clockwise when the 120 V a.c. output is not in use, and
before connecting or disconnecting test leads at these terminals.
7. The 'Common' terminal is connected to earth for measurement purposes. Avoid circumstances where current will
be passed through this internal connection.

Cautions

1. The test set is fitted with high breaking capacity (HBC) ceramic IEC 127 fuses. It is essential that any replacement
fuses fitted to the instrument conform to this specification. Glass fuses must NOT be used due to their low
rupturing capacity.
2. It is important to note that the main a.c. outputs are rated at open circuit voltages and short circuit currents
e.g. 0—24 V and 0—100 A, which means that it is not possible to get the full 100 A output current when the
output voltage is 24 V. (The impedance of the item under test affects the current or voltage output.)
3. Be careful not to exceed the permitted duty cycle of the instrument (see Specification for details).
4. The instrument contains static sensitive devices. If the instrument casing is opened for any reason (this will
automatically invalidate any warranty covering the instrument), care must be exercised in handling the printed
circuit boards. This should be done in accordance with DEF STAN 59-98 and BS5783, specifications for handling
electrostatic sensitive devices. Printed circuit boards containing such devices are identified either by a yellow
warning label, or by a yellow legend and a large yellow dot on the p.c.b.

Preliminary Procedure

1. Having established the output required, connect the relay to be tested to the SCITS100, via the appropriate
terminals.
2. Check that the two output controls are turned fully anti-clockwise.
3. Check that the 'Set/Test' switch is set to '0' (off) position.
4. Ensure that the instrument is properly earthed (grounded). For extra safety, the operator is advised to use the
external earth (ground) terminal and connect it to a known earthing (grounding) point.
5. Connect the Secondary Current Injection Test Set to a suitable supply. Turn the input power switch from
0 (OFF) to 1 (ON), and the two digital displays will read zero.

Testing Procedure

6. Select the desired position on the range switch. (Note: This switch will only affect the display and not the output).
Although the display may read zero current this does not necessarily imply the absence of voltage across the
terminals. Caution should therefore be exercised when operating the instrument.
7. Select the 'Set' position on the 'Set/Test' switch. The lamp between this switch and the main output control
should illuminate, indicating that a voltage is present at the terminals, and with the leads connected to the device
under test, a current flows. The counter however, is disabled in this position.
Caution:— Do not leave the instrument on 'Set' for longer than is necessary, as this may seriously damage the
relay under test.
8. Turn the main output control clockwise until the desired output is displayed on the meter.
Note:— The main output control may appear a little coarse on some ranges, inherent with this type of display.
With care, the output may be set more accurately by choosing the output terminal which gives adequate
sensitivity. (The 0—24 V, 0—100 A terminal gives the greatest sensitivity but the impedance of the load
under test may preclude its use.)
9. Return the 'Set/Test' switch to the '0' (off) position and wait until the relay returns to its initial position (since
during the setting procedure the disc inside an I.D.M.T., for example, will have rotated away from its rest position).
10. Set the time counter function to the appropriate position as outlined opposite, using the counter function switch.
Note:— If the time counter display is not reading zero, then set it so by pressing the 'Reset' push-button.
11. Once the output has been set up, and the 'Test' position selected, the SCITS100 will inject the previously set
current or voltage from the terminals.
12. Upon completion of the test, return the 'Set/Test' switch to the '0' (off) position.
13. For further tests:—
a) If further readings are necessary at the same output setting, wait for the relay to regain its normal position,
reset the counter and turn the 'Set/Test' switch to the 'Test' position again. Be careful not to exceed the permitted
duty cycle of the instrument.
b) If another output level is required, turn the main output control fully anti-clockwise and repeat the above
procedures from step (6).
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