Amprobe AM-270 Spécifications télécharger pdf (Page 10)

• Overheated transformers, generators and motors to burn out faster than

normal

• Circuit breakers to trip prematurely

• Fuses to blow

• Neutrals to overheat due to the triplen harmonics present on the neutral

• Bus bars and electrical panels to vibrate

Crest Factor

Crest Factor is the ratio of the Crest (instantaneous peak) value to the True

RMS value, and is commonly used to deﬁne the dynamic range of a True RMS

DMM. A pure sinusoidal waveform has a Crest Factor of 1.4. A badly distorted

sinusoidal waveform normally has a much higher Crest Factor.

NMRR (Normal Mode Rejection Ratio)

NMRR is the DMM’s ability to reject unwanted AC noise effect that can cause

inaccurate DC measurements. NMRR is typically speciﬁed in terms of dB

(decibel). This series has a NMRR speciﬁcation of > 60dB at 50 and 60Hz, which

is a good and deﬁnite ability to reject the effect of AC noise when making DC

measurements.

CMRR (Common Mode Rejection Ratio)

Common mode voltage is voltage present on both the COM and VOLTAGE input

terminals of a DMM, with respect to ground. CMRR is the DMM’s ability to reject

common mode voltage effect that can cause digit rolling or offset in voltage

measurements. This series has a CMRR speciﬁcations of > 80dB at DC to 60Hz in

ACV function; and > 120dB at DC, 50 and 60Hz in DCV function. If neither NMRR

nor CMRR speciﬁcation is speciﬁed, a DMM’s performance will be uncertain.

OPERATION

CAUTION

Before and after hazardous voltage measurements, test the voltage

function on a known source such as line voltage to determine proper

meter functioning.

DC Voltage, AC Voltage, & Hz Frequency Functions

ImV function defaults at DC. Press SELECT button momentarily to select AC.

Press the Hz push-button momentarily to activate or to exit Hz.

1 2 ... 5 6 7 8 9 10 11 12 13 14 15 ... 27 28

Pas de commentaire

Amprobe AM-270 Spécifications Page 10