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Line Leakage Measurements
- This test is performed in order to determine the leakage current through the isolation
barriers which could flow through the user/patient during operation of a product
- The current through the earth conductor is measured (which is known as earth leakage
current)
- The touch current is measured by using a Measuring Device (also known as a MD). This
simulates the impedance of the body if a patient would come contact with teh product
being tested.
- The test is made in normal condition and also under single fault conditions
- Normal condition means with normal polarity and reverse polarity (possible with
Schuko)
- Single errors: open neutral condition/ interrupted ground connection
- All combinations of reverse polarity and single fault conditions are tested (a full
sequence of 8 tests)
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AC source Requirements:
- Some standards (e.g. IEC 60601-1 - Medical) require testing with higher (e.g. 110 %)
mains voltage For example in Europe, you would need to test the product at 253 or 264V
instead of the mains voltage
- Testing at maximum specified power frequency
- Typically an isolated galvanic source is needed
Solution approach:
- Electronically programmable AC sources allow voltages and frequences independent
from supply network
- Associated Research stand alone Line Leakage Testers and combined Instruments are
able to control the power sources that are offered by their sister comapny named
Associated Power Technologies. The product range goes from 400VA-18KVA 3 Phase
- Omnia II 8207/8257 have a 500W/630VA internal programmable AC source
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Chart showing the 3 Different Types of Line Leakage Tests.
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Here are two Diagrams taken from the front panel of the OMNIA II showing the Set up of
an Earth Leakage Test. Here you are changing the Fault Condition. This example showing
opening and closing the Neutral Condition.
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Here is a chart showing the 8 different Failure Combinations that need to be performed per
Line Leakage test on a product.
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This picture shows the DUT connection
- AR Omnia II tester have internal relays for performing all of the different tests
- AC supply comes from an external or internal AC power source
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Earth Leakage Test Diagram with no fault conditions
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Earth Leakage Test Diagram showing a Reverse Polarity Condition
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Earth Leakage Test Diagram showing Neutral Open Condition
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Touch Current Test
- Leakage current flowing through the user when touching the product
- The protective Earth is interrupted during the measurement
- If exposed metal parts on a prodcut are not grounded, it is required to measure all metal
parts against ground
- Diagram shows how a touch current test would be performed
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Patient leakage current and leakage current via applied parts
- Testing of the leakage current flowing via the patient when connected to an application
part
- Leakage current flowing between different application parts
- The MD is connected by external connections as you can see in the diagram. You would
use the Probe Hi & Probe Lo measurement to perform the testing.
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Here is an example of how to perform applied part testing with the use of a SC6540
Scanner.
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Mains on applied part leakage test
- The DUT is powered via an AC Source
- The applied part are powered by a secondary power source, the current flowing through
the MD is measured
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SC6540 High voltage and high current switching unit
- Master Scanner with integrated Automated interface such as GPIB/Ethernet/USB - RS232
- Slave Scanner controlled by safety compliance analyzer
- Provided below are typical connections between Omnia II instrument and SC640 scanner
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Diagram shows how you can perform an automated ground bond test
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Diagram shows how you can perform an automated hipot mains DUT supply test
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Diagram shows how you can perform an automated hipot test on applied parts or patient
connections
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Diagram shows how you can perform an automated earth leakage current test
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Diagram shows how you can perform an automated patient leakage test on Applied Part 1
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Diagram shows how you can perform an automated patient leakage test on Applied Part 2
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Diagram shows how you can perform an automated mains on applied part leakage test on
Applied Part 1
We are using a 8207 OMNIA II with a built in power source which powers the device and
we are also using a secondary power source.
The reason why we are connecting the External Power Source to perform the Mains on
Applied Part test to two different scanners is because it is to account for polarity reversal
on Switch S9 within the 60601 Standard Figure 16 Section 8.7.4
The second reason you are doing a polarity reversal is because you need to isolate your
measurement circuit from the power source. Your measurements would not be accurate if
you don’t use two scanners.
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Diagram shows how you can perform an automated mains on applied part leakage test on
Applied Part 2
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The Entire System would be controlled by the Autoware II software to provide a full
Medical Test Solution.
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