MI 3321 MultiservicerXA
Machine testing operating mode
137
Notes:
The autotest sequence is immediately stopped if any incorrect condition is
detected, e.g. excessive Uc or trip-out time out of limits.
The RCD t test will trip the RCD. Assure that the instrument is not powered from a
socket protected by the tested RCD.
9.2.7
PRCD test
Description in chapter
6.2.10 PRCD test
can be used as reference.
9.2.8
Discharging Time (Residual voltage test)
If large capacitors in machines are disconnected from supply there is often a remaining
(residual) charge on internal machine components. Live parts having a residual voltage
greater than 60 V shall be discharged to 60 V or less within a time period of 5 s after
disconnection of the supply.
For plugs or similar devices with exposed conductors (for example pins) if plugged out
the discharge time shall be discharged to 60 V or less within a time period of 1 s after
disconnection of the supply.
Measuring principle
The test leads are connected to terminals where residual voltage is to be measured.
The machine is switched ON, the voltage on terminals can be of a.c. or d.c. type.
Phase 1:
The instrument monitors the voltage and internally stores the peak voltage
value.
Phase 2:
The machine is disconnected from the power supply and the voltage at the
test terminals starts to fall. Once the voltage falls for 10V the instrument starts the timer.
Phase 3:
After the voltage drops below an internally calculated voltage value the timer
is stopped. The instrument recalculates the measured time to a value as it would be if
the disconnection occurred at the maximum voltage value.
L
N
V
MultiServicer
MI
XA
3321
rest
voltage
test
EQUIPMENT UNDER
TEST
disconnect
TEST
TP1-L
TP1-N
Test circuitry
