User's Manual

M2540-92000-01 A M2540 Ultrasound System Field Service Manual Page 92
Performance Tests: Electrical Safety Tests
4. Make the appropriate connections between the analyzer and the ground lug on the
ultrasound system’s I/O panel.
5. Read chassis ground resistance in milliohms. Flex the ultrasound power cord during the test
to detect intermittent changes in resistance value.
6. Record the highest resistance value measured in step 5. Check that the highest resistance
value is within the limit specified in Figure 6-1on page 91.
NOTE If the reading exceeds the specified limit, check the power cord and the associated
primary wiring.
A comprehensive ground impedance measurement can be performed using the safety analyzer.
The impedance test drives a load current through the ground wire while measuring the AC
voltage drop across the entire length of the power cord and to the system chassis. The reading
will be in milliohms.
Ground Wire
Leakage
Current Test
This test checks the entire system for leakage on chassis ground wires. Figure 6-2 on page 93
shows the basic electrical concept of the test. Use a safety analyzer and complete the procedure
that follows the figure.
CAUTION If the safety analyzer is used for an extended period, it may be damaged by the high current draw
of the system.
WARNING
This test can be hazardous. Avoid any contact with line voltage. Any time during the test that the
ground connection is open, do not touch the M2540A chassis or the patient cable.