Chapter 1 Overview; Purpose; Description - Ametek 303B User Manual

OVERVIEW
This manual describes operation; provides application, installation, and
maintenance data; and lists user replaceable parts for the AMETEK Model
303B Moisture Monitor. Gas correction factor tables are given in Appendi-
ces A through C. A glossary of terms is given in Appendix D.

Purpose

The Model 303B measures the water vapor content of most gases, or a
mixture of gases, in ppmv or lb/MMscf in Division 2 areas.

Description

The 303B (figure 1-1) is a small, compact, portable, weather proof (NEMA
3R) instrument that operates from an external AC or DC source, or an in-
ternal battery. An internal flow meter is provided for use as a flow indica-
tor..
• The front panel contains ten membrane key switches, ten windows to
view LED's that show the status of the various functions, two trans-
parent windows to view the flow meters and the output display, and
two access holes for flow adjustment
• The electrolytic cell, the battery, and two pc boards (cpu/display and
power supply) are mounted inside.
• The rear panel contains sample connector fittings, and watertight CGB
connectors for the AC or DC power cord and the analog/output alarm
wires.
Battery operating life is directly related to the moisture level being meas-
ured. At maximum moisture levels, power can be sustained for 24 hours;
at low moisture levels, operation can be sustained for over 1 week.
While running, if for any reason external power is lost, the analyzer au-
tomatically switches to battery operation. On external power, the bat-
tery automatically recharges to full capacity, time permitting, in about 24
hours.
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Overview 1-1