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7. Electrical safety test
Important: After opening the cover of the unit for repair, the electrical safety test is indispensable.
7.1 Dielectric strength test
Caution: 1) Be sure to keep away from the equipment while the high voltage is being applied to the EPK-p.
2) This test is one kind of destructive tests. Multiple tests may damage the EPK-p.
1) Connect the probes of the dielectric strength tester according to Table-2. Refer to Fig-4 for the
connection.
2) Set the voltage according to Table-2, applying HV time to 60 seconds and the cut off current to 15mA,
then start the test by pressing the start button on the tester.
3) Confirm that there is no break down during the test period 60 seconds.
No.
Dielectric strength test
Probe (+)
Probe (-)
Apply voltage
1
Primary circuit to Chassis
Point-A
Point-B
1,500VAC
2
Primary circuit to Patient circuit Point-A Point-C 4,000VAC
3
Signal terminal to Patient circuit
Point-C
Point-D
1,500VAC
Point-A: Point of shorted together with the live and neutral terminals of the AC cable.
Point-B: Equipotential terminal of the EPK-p.
Point-C: Equipotential wire of the dummy scope for dielectric strength test.
Point-D: Video signal BNC connector (outer shell) of the EPK-p.
7.2 Protective earthing circuit resistance
Measure the protective earthing circuit resistance with a low resistance meter and check whether it is within
the value described below: Refer to Fig-5.
1) Resistance between GND pole of AC inlet (Point-A) and Equipotential terminal (Point-B). It must be less
than 0.1 ohms.
2) Resistance of GND wire within AC cable (between Point-C and D). It must be less than 0.1 ohms.
Table-2 Dielectric strength test condition
Dummy scope for Dielectric strength test
Point-A
Point-C
Point-B
Point-D
Dielectric strength tester
Probe-(+)
Probe-(-)
Fig-4 Dielectric strength test
Fig-5
Protective earthing circuit resistance measurement
Point-B
Point-D
Low resistance meter
Probe-(-)
Probe-(+)
AC cable
AC inlet
Point-A
Point-C
Dummy scope
•
Every wire of the scope
connector is connected to
the one wire (indicated in
green above).
•
No PCB, no light
coherent bundle.
•
You can make the
dummy scope like above.
•
It has yet to be available
as a Special Tool.
EPK-p
EPK-p
