Functional Description; Discharger Test; Insulating Resistance Measurement At 50V/20 Mω Or 100V/200 Mω Or 500V/2000 Mω - Metrix MX 604 Manual De Instrucciones

3.

FUNCTIONAL DESCRIPTION

3.1.

Discharger test

Switch the commutator to the position
Surge arrester tests can be conducted in two different ways:
a) Table measurement
The instrument is equipped with a surge arrester support unit. The arrester to be
tested is then inserted into the appropriate recess. Press the push button to
initiate measurement.
b) Onsite measurement
Connect the earth lead and the probe with the tripod plug to the instrument.
Place the two ends of the probe tips of the leads on the surge arrester to be
tested. Activate the probe push button to initiate measurement. The surge
arrester support clamp can be used for this type of measurement.
Read the voltage value on the 600 V scale :
•
Accuracy : class 10
•
Open-circuit output voltage
•
Short-circuit current
The surge arrester support clamp and the surge arrester support unit must
not be connected to live circuits.
3.2. Insulating resistance measurement at 50V / 20 MΩ, or 100V / 200 MΩ, or 500V / 2000MΩ
High voltage is generated at the terminals of the resistor to be measured. The voltage drop
measured at the terminals of a known internal resistor in series with the resistor to be
measured is used to deduce the value of the resistor.
Tests should only be carried out on circuits out of voltage (the mains light on the instrument
scale must be off after disconnecting the test leads and before pressing the probe push
button).
Connect the circuit to be measured to the instrument terminals, before starting the
measurement.
Measurement results may be distorted by the impedances of additional circuits connected in
parallel or by transient currents.
• Measurement range :
When the circuit is open (infinite Rx), the needle comes to a stop on the right.
The measured value is read off three specific logarithmic scales:
2000 MΩ / 500 V, 200 MΩ / 100 V and 20 MΩ / 50 V, each covering 3 decades.
• Measurement current : ≥ 1 mA for R = 500 kΩ
• Protection of inputs :
• No load voltages :
• Accuracy : class 10
12
.
(10 % of scale range according to ref. conditions)
< 950 V
DC
< 400 µA
100 kΩ to 20 MΩ at 50 V
100 kΩ to 200 MΩ at 100 V
5 MΩ to 2000 MΩ at 500 V
≤ 4 mA in short-circuit
up to 600 V
rms
< 75 V on the 50 V range
DC
< 150 V on the 100 V range
DC
< 750 V on the 500 V range
DC
(10% of scale range according to ref. conditions)
Chapter II
500 kΩ acc. IEC 61557-2,
with BAT test in the black area
Discharger tester