Principle Of Operation; Hardware Configuration; Figure 2 Principle Of Operation - Honeywell MagneW 3000 Plus Application Manual

Principle of Operation

The MagneW 3000 PLUS flowmeter's
operating principle is based on
Faraday's Law: The voltage induced
across any conductor, as it moves at
right angles through a magnetic field, is
proportional to the conductor's velocity.
The detector fits on the pipe and
measures the flow. The detector's
excitation coils receive power from the
converter. These coils create a
magnetic field at a right angle to the flow
direction.
As the conductive liquid flows through
this magnetic field, a voltage which is
proportional to the liquid flow velocity is
produced across the electrodes. The
detector sends these voltage signals to
the converter. Refer to Figure 2.
The converter, which holds the circuitry
that calculates and displays the flow
data, converts the detector signals into
outputs for recording and control
instrumentation.
The relationship between the liquid flow
velocity and the voltage is expressed in
Faraday's formula:
E is proportional to V x B x D
where:
E = Induced Electromagnetic
Voltage
Voltage generated by the flow of
the conductive liquid through the
magnetic field of the flowmeter.
V = Average Flow Velocity (m/s)
The average velocity of the liquid
through the cross section of the
flowmeter.
B = Magnetic Flux Density
The strength of the magnetic
field generated by the field coils.
D = Inside Diameter of the Pipe
The distance between the
electrodes which detect the
signal voltage (E) that is
generated.
This means that the voltage (E)
depends on the average flow velocity
(V), the magnetic flux density (B), and
the inside diameter of the pipe (D).
2
Exciting
current
Power
Supply
Liquid Flow
(average velocity V)
Figure 2—Principle of Operation
The MagneW 3000 PLUS flowmeter is available as either:
• an integral unit—converter mounted on detector, or
• a remote converter/remote detector.
The detector is mounted to the process piping, using one of the following types of
connections:
• wafer,
• flange,
• union,
• hose, or
• IDF or Tri-clamp.
The type of connection used is dependent upon diameter size and the application.
Where applicable, gaskets are supplied unless the grounding rings are made of
SUS material.
If using the remote converter/remote detector combination, either a wall- or pipe-
mounting kit for the converter and cables to connect the converter and detector
are needed.
MagneW 3000 PLUS Specification and Application Guide
Detector
Core

Hardware Configuration

Measuring Pipe
(inside diameter D)
Magnetic Field
(flux density B)
Output
Converter
Signal
Electrode (emf E)
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