Fukuda Denshi FCP-7101, Service Manual

Page: 58 / 170

Chapter 3
3 - 24
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Safety inspections (4 items)
To assure safety of medical equipment, testing methods and measurement
equipment are prescribed in the safety test standards with respect to leakage
current that affects human body. To perform inspections, make the setting
and pass/fail evaluation using a leakage current gauge that meets the
requirements for measurement of medical equipment.
WARNING
If, during a safety inspection, a value that exceeds the allowable limit is
detected, immediately stop using the unit and replace the defective part or
make proper repairs. Otherwise a serious accident may result.
Before checking the leakage current
There are a number of conditions for measuring leakage current. Adopt
the maximum value obtained as measurement value.
It is also very important to compare the obtained value with past
measurement values to confirm that no significant difference is observed.
To measure the leakage current, use a leakage current gauge provided with
human body simulation impedance (network) as shown below.
R1
R2 C1
V
R1 :10k ± 5% (No lead)
R2 :1k ± 1% (No lead)
C1 :0.015µF ± 5% (No lead)
V :Voltmeter
Measure the voltage at both ends of the human body simulation impedance,
and substitute the obtained value into the following formula to obtain
current value.
Measured voltage (V)
1000
= Measured current (mA)
About leakage current gauge
Since leakage current has significant effect on human body, testing methods,
performance of measuring instrument, value limit of leakage current, etc.
are specified by various laws and standards. Use a measuring instrument
conforming to “IEC 60601-1,” which is standard specification of electrical
appliances for medical application, to measure the leakage current of this
instrument.