User manual

10 GMC-I Messtechnik GmbH
5 Maintenance – Recalibration
5.1 Housing
No special maintenance is required for the housing. Keep outside
surfaces clean. Use a slightly dampened cloth for cleaning. Avoid the
use of cleansers, abrasives and solvents.
5.2 Batteries
Check the batteries at short regular intervals to makes sure no
leakage has occurred. If leakage occurs, electrolyte must be fully
removed from the instrument and new batteries must be installed.
Remove the batteries from the battery compartment if the measuring
instrument will not be used for a lengthy period of time. Refer to
chapter 3.2 regarding battery replacement
Attention: If the LED lights up red before or during measurement, the
batteries must be replaced immediately.
Use only recommended battery types (see chapter 3.2).
5.2.1 Details on Power Consumption and Operating Time
Low-Resistance Measurement
The instrument draws the most power from the batteries when the
value of the contact resistance is the lowest.
Power consumption does not exceed the value of 0.4 A.
Insulation Resistance Measurement
Power consumption from the batteries depends on the selected test
voltage and the actual value of the insulation resistance, i.e. on the
load imposed on the source of the measuring voltage U
N.
The table
below specifies the power consumption from the batteries for the
indicated parameters.
The following table lists the number of possible measurements with
one set of alcaline batteries by taking into account the power con-
sumption from the batteries.
The number of possible measurements depends on the following conditions:
• one measurement takes 1 minute
• the insulation resistance complies with the requirements of the
standard
(power consumption from the battery in accordance with
column 3 of the table above).
5.3 Replacing the Fuse
The low-resistance measuring range is protected with a fuse, see
chapter 6. The fuse blows if a voltage is applied to the test probes
which may cause damage to the instrument as a result of its
magnitude or polarity.
Adhere to the prescribed sequence when replacing the fuse:
Ð Remove the test probes from the device under test.
Ð Loosen the 3 screws in the housing base.
Test Voltage
U
N
R
X
measured at I
BAT
(U
BAT
= 6 V)
(*if LED lights up green, pointer oscillates and there is no acoustic signal,
the transformer is overloaded)
500 V 0 kΩ / < 1 A * 0.1 MΩ / < 1.1 A > 1 MΩ / < 0.6 A > 400 M Ω / < 0.3 A
250 V 0 kΩ / < 1 A * 0.1 MΩ / < 0.4 A > 500 k Ω / < 0.4 A > 400 M Ω / < 0.2 A
100 V 0 kΩ / < 1 A * 0.1 MΩ / < 0.2 A > 200 k Ω / < 0.3 A > 400 M Ω / < 0.2 A
Test Voltage U
N
AlMn Battery min. 2300 mAh
500 V > 300 measurements
250 V > 500 measurements
100 V > 750 measurements