AMETEK Ls Series - Manual (Page 53)

User Manual Lx / Ls Series
49
3.7 Basic Initial Functional Test
CAUTION: Work carefully when performing these tests; hazardous voltages
are present on the input and output during this test.
Refer to Figure 3-3 for the required functional test set up. Proceed as follows to perform a basic
function check of the power system:
1. Verify the correct AC line input rating on the nameplate of the Lx/Ls unit(s) and make sure
the correct three-phase line voltage is wired to the input of the Lx/Ls before applying input
power.
2. Connect a suitable resistive or other type load to the output of the Lx or Ls. Suggested load
values for the low voltage range rounded up to the nearest 0.1 Ohm are shown in Table 3-9
for the Lx Series and Table 3-10 for the Ls Series.
For the high voltage range, the resistor values must be multiplied by four. For models with
–
HV or –EHV voltage range option, recalculate these values by adjusting for the voltage range
value. Make sure the power resistor has sufficient power dissipation capability for full load
test and that the load used does not exceed the maximum power rating of the AC source.
For three phase configurations, this test can be performed on one phase at a time if needed.
3. Connect an oscilloscope and DMM / voltmeter to the AC source output. Set both for AC
mode.
4. If the correct voltage is present, turn on the Lx/Ls unit(s) by closing the On/Off circuit breaker
on the front panel of both chassis.
5. Set the output voltage to 0 volt and close the output relay with the OUTPUT ON/OFF button.
There should be little or no output although the DMM may show a noise level, especially if
the DMM is in auto ranging mode.
6. Select the Set screen and use the voltage shuttle to program a small voltage (20 VAC).
Observe the DMM reading. The reading should track the programmed voltage.
7. Also monitor the scope. The output should be a sinusoidal voltage waveform.
8. If the output tracks, increase the voltage till you reach 80 % of the voltage range or more.
Check the output voltage reading and waveform.
9. Select the measurement screen by pressing the Meas button. The output voltage, current
and power will be displayed. For three phase configurations, use the PHASE button to select
individual phase data. If all phases are loaded equally, the same current and power should
be visible for all three unless the voltages are not programmed to the same level. If only one
phase is loaded, current and power will only be shown for the loaded phase.
In the unlikely event the power source does not pass the functional test, refer to the calibration
procedure in Section 6 or cal
l California Instrument’s customer satisfaction department for further
assistance.