M2540-92000-01 A M2540 Ultrasound System Field Service Manual Page 54
Theory of Operation: Transducer Safety Testing: Test Setup and Theory
Insertion depth:
•For transthoracic and endocavity transducers, submerge the head and 5 cm of the cable,
being careful to not submerge the connector.
•For TEE transducers, submerge all of the flexible shaft that would normally enter the body of
the patient: 100 cm for adult TEE, 60 cm for pediatric TEE.
Theory of the Transducer Leakage Current TestLeakage current Ichassis, driven by the line supply, flows through the stray capacitance C between
the primary wiring and the system’s metal chassis.
Table 4-1 Key for Figure4-4
A = Microammeter in the safety analyzer
Imeasured = Leakage current
S = Switch that connects the ammeter either directly to the chassis or
through the ECG lead wire. (This is the mode selector on the Safety
Analyzer. Select ECG for transducer leakage and Case Leakage, or select
Ground Conductor for chassis leakage.)
C = Stray capacitance from the system's power wiring to the chassis.
Z=
Impedance between the transducer’s metal parts and the test electrode:
≈ 800 KΩ if the outer insulating layer is intact
< 500 Ω if the outer layer is compromised