Operation Manual

26 GMC-I Messtechnik GmbH
I
AP
Leakage Current from the Applied Part (alternative patient leakage current, mains at applied part)
Applications
This measurement is only performed for types BF and CF applied
parts. For type BF and CF applied parts, measurement is required
for all interconnected patient ports used for a single function of
the applied part, or measurement must be executed as specified
by the manufacturer.
When testing measuring instruments with several applied parts,
each must be connected, one after the other, and measuring re-
sults must be evaluated on the basis of the limit values shown in
table 2. Applied parts which are not included in the measurement
must be kept potential-free.
Definition of Leakage Current from the Applied Part
Current which flows from power packs and exposed conductive
parts of the housing to the applied parts.
Definition of Direct Measurement
Current which is caused by an undesired interference voltage at
the patient, and which flows from the patient to ground via the pa-
tient ports for a type BF or CF applied part.
Definition of Alternative Measurement
Alternative patient leakage current is current which flows through
the conductors of the device which are connected to each other
(L/N/PE) to the patient ports.
Prerequisites:
A high-impedance power supply is connected between one
patient port at a time, and the exposed metallic parts of the
housing (which are connected to each other). The mains terminals
are short-circuited and are connected to the same point on the
housing.
Direct Measurement Method (mains at applied part)
The current which flows over the insulation of the device under
test is measured separately for each applied part.
The device under test is operated with mains power in this case.
The value which has been adjusted to nominal line voltage is dis-
played (see section 4.3).
Alternative Measurement Method (alternative patient leakage current)
The current which flows over the insulation of the device under
test is measured separately for each applied part.
Measurement is always performed using an AC source with
current limiting. Differing mains voltages are taken into
consideration.
Type of Test Current Parameter
– DIR Mains at applied part (applied parts plugged in)
– ALT Eq. patient leakage current (applied parts plugged in)