Measurements; Voltage Measurement - Gossen MetraWatt METRAHIT ENERGY TRMS System Multimeter Operating Instructions Manual

5

Measurements

5.1 Voltage Measurement

Notes Regarding Voltage Measurement
• The multimeter may only be operated with installed batteries or re-
chargeable batteries. Dangerous voltages are otherwise not indicated,
and the instrument may be damaged.
• The multimeter may only be operated by persons who are capa-
ble of recognizing contact hazards and taking the appropriate
safety precautions. Contact hazards exist anywhere, where volt-
ages of greater than 33 V (RMS) may occur.
The test probes may only be only gripped up to the finger guard.
Do not touch the metallic test probes under any circumstances.
• Avoid working alone when taking measurements which involve
contact hazards. Be certain that a second person is present.
• Maximum permissible voltage between the connector sockets, (9
and 10) and ground (8) is 600 V for measuring category III and
300 V for measuring category IV. An acoustic signal is generated
at a display value of greater than 600.0 V in the 600 V range (in-
termittent acoustic signal: 250 ms on, 250 ms off).
6
• Power limiting: < 6 x 10 Volts x Hertz.
• Be prepared for the occurrence of unexpected voltages at devices
under test (e.g. defective devices). For example, capacitors may
be dangerously charged.
• No measurements may be made with this instrument in electri-
cal circuits with corona discharge (high-voltage).
• Special care is required when measurements are made in HF
electrical circuits. Dangerous pulsating voltages may be present.
GMC-I Messtechnik GmbH
Measurements: V/Hz/dB – PQ/
– MHz/% – /nS/R
– /
SL
• Be aware of the fact that dangerous voltage spikes are not displayed
during measurement with the low-pass filter.
We recommend measuring voltage without the low-pass filter first, in
order to be able to detect any dangerous voltages.
• Be absolutely certain that the measuring ranges are not over-
loaded beyond their allowable capacities. Limit values are in-
cluded in section 8, "Technical Data", in the table entitled
"Measuring Functions and Measuring Ranges" in the "Overload
Capacity" column.
• With the rotary switch in the V position, the instrument is
always in the 6 V measuring range immediately after it's
switched on. As soon a the MAN / AUTO key is pressed, and as-
suming the measured value is less than 600 mV, the instrument
is switched to the mV measuring range.
Scope of Functions, Voltage Measurement
Function
V AC / Hz TRMS, dB

(Ri  9 M) 1
1
V AC / TP-Filter 1 kHz

(Ri  9 M) TRMS
V AC+DC TRMS

(Ri  9 M)
V DC (Ri  17 M)


MHz at 5 V AC

Duty cycle as %
Frequency bandwidth
100 kHz
1
A 1 kHz low-pass filter can be used in this case, in order to filter out high frequency
pulses of greater than 1 kHz, for example when performing measurements at
pulsed motor drives.
– Temp – /m – W/Wh – A/Hz/thd
25