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4535 612 34161 HD3 Service Manual Page 134
CSIP Level 1 Performance Tests: Electrical Safety
10. Check that the highest current value measured in step 8 and step 9 is within the limit speci-
fied for Single Fault condition in Figure 6-3. Values exceeding the limits may indicate a fault in
the transducer housing or the cable sheath. To locate a fault precisely, repeat the measure-
ment while slowly inserting the transducer into the saline. The aberrant reading appears
when the fault in the cable enters the saline.
NOTE Endocavity transducers have a grounded jacket just under the outer plastic skin of the
cable. Their leakage currents can measure within the specified limits even if there is a
fault in the outer skin. Step 11 tests for this condition.
11. In normal polarity with an open ground condition imposed, measure ground wire leakage
(see “Ground Wire Leakage Current Test” on page 129). Compare this to the highest value
for transducer leakage current, Single Fault condition obtained in step 10. If the transducer
leakage is greater than 80% of the chassis leakage, there is a fault in the transducer. To locate
the fault, slowly insert the transducer in the saline, as in step 10.
Transducer Isolation Leakage Current Test
Figure 6-4 shows the basic electrical concept of the Transducer Isolation Leakage Current test.
The transducer is submerged in a container of saline solution. AC Mains voltage is introduced
into the saline solution, and leakage current in the transducer is measured using a safety analyzer.
Complete the procedure “To test transducer isolation leakage current” on page 136.