Page 1
A3 ALPHA® Meter
Electronic Meter for
Electric Energy Measurement
Technical Manual
TM42-2190B
US English (en)
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1. Introduction A3 ALPHA Meter Technical Manual
The A3 ALPHA Meter
Upon its introduction in 1992, the ALPHA meter set the standard for
totally electronic, high function, multiple tariff electricity metering. As
features have been continually added, the ALPHA meter has been able
to maintain its position as the leader in solid state metering
technology. Building on patented ALPHA meter technology, the
A3 ALPHA meter is the first Elster Electricity meter to support the
American National Standards Institute (ANSI) C12.18, C12.19, and
C12.21 standards.
The A3 ALPHA meter provides a meter design platform that supports
a variety of metering requirements. From a simple one–rate kWh and
kW demand meter up through a multi–rate, real/reactive, bi–
directional meter that automatically validates the meter service
connections, provides instrumentation readings, performs power
quality monitoring, logs events, and provides load and
instrumentation profile readings with remote communications—the
A3 ALPHA meter does them all.
This manual is a guide to the features, flexibility, and operating
characteristics of the A3 ALPHA meter.
The A3 ALPHA meter is a totally electronic polyphase electricity meter
and integral register. This meter provides the following general
functionality on either a single–rate or time–of–use (TOU) basis:
■ collects energy use and demand data
■ processes energy use and demand data
■ stores energy use and demand data
See Figure 1-1 for an example of an A3 ALPHA meter.
1-2 TM42–2190B 2003.February.28
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A3 ALPHA Meter Technical Manual 1. Introduction
Standards Compliance
ZA320F000L4-AD
TYPE A3RL Mult. by
SERIAL #
LOCK
CL20, 120 TO 480V, 4WY or 4WD, 60Hz
TEST
FM 9S (8S ) Watt hou r Met er
R3.01.00-YYWWDD XXYY-AAAAAA
Figure 1-1. A3 ALPHA meter
PREV SEAS
RATE
ABCD
CUM
MAX
ARhKW
TEST
CONT
RESETS
TOTAL
01 957 166
* KZG001957166 *
Pkh
ALT
VTR
CTR
EOI
Kh 1.8
P/R 24
TA 2. 5A
:1
:5
O
P
E
N
The A3 ALPHA meter meets or exceeds the ANSI standards for
electricity metering, and it is intended for use by commercial and
industrial utility customers.
Number Date Title
ANSI C12.1 1995 American National Standard for Electric Meters –
Code for Electricity Metering
ANSI C12.10 1997 Electromechanical Watthour Meters
ANSI C12.18 1996 Protocol Specification for ANSI Type 2 Optical Port
ANSI C12.19 1997 Utility Industry End Device Data Tables
ANSI C12.20 1998 American National Standard for Electricity Meters 0.2
and 0.5 Accuracy Classes
ANSI C12.21 1999 Protocol Specification for Telephone Modem
Communications
2003.February.28 TM42–2190B 1-3
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1. Introduction A3 ALPHA Meter Technical Manual
Benefits
Reliability
The A3 ALPHA meter, part of the ALPHA line of meters, uses the
patented ALPHA meter technology for measurement and accurate
calculation of energy quantities. With over 2 million ALPHA meters in
operation throughout the world, the A3 ALPHA continues the
tradition of reliable electronic meters.
The A3 ALPHA meter can use its internal crystal oscillator or the
power line frequency to maintain time and date functions. The crystal
oscillator can be used when the power line frequency is known to be
too unstable for accurate timekeeping.
The A3 ALPHA meter contains circuits that have been designed to
function with the battery to provide a long battery life. Due to the low
current drain, the service life of the lithium battery can exceed the life
of the meter.
The A3 ALPHA meter uses nonvolatile memory to store its data. If the
power fails, the data is preserved.
Maintainability
The A3 ALPHA meter is easy to maintain. Meter and register functions
are fully integrated on a single, surface–mount technology circuit
board. This combines with the modular design of the meter for
quickly and easily replacing parts.
ANSI Standard Communication
The A3 ALPHA meter complies with the ANSI C12.18, C12.19, and
C12.21 standards. These standards include communication protocols
for a wide range of metering products. They are the basis for common
industry data structures and a common protocol for transporting the
data structures. By supporting the ANSI protocols, the A3 ALPHA
meter will reduce maintenance cost, make it easier to add new
products to existing systems, and provide an open standard for meter
data communications.
Adaptability
The A3 ALPHA meter allows configuration for custom TOU rates,
offering a broad range of demand and TOU operations. Practically all
common services and mounting configurations have been accounted
for, and functional upgrades are easily performed as new situations
arise. The wide operating range allows installation at any of the
common meter voltages.
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A3 ALPHA Meter Technical Manual 1. Introduction
Economy
The A3 ALPHA meter saves both time and money. It will dramatically
increase personnel productivity due to the following features:
■ no user calibration required (factory calibrated)
■ reduced testing times
■ fewer styles to learn and maintain
■ automated data retrieval
■ system service verification
■ onsite instrumentation displays
■ power quality monitoring (PQM) tests
■ event logging
Security
The A3 ALPHA meter is tamper–resistant. Passwords may be specified
that prevent unauthorized access to meter data. Since there are no
moving parts in this fully electronic meter, tampering that would
normally affect the electromechanical meter will not affect the
A3 ALPHA meter. The optional PQM feature or the optional
instrumentation profiling (or both) can be used to detect possible
tampering of energy measurements.
Accuracy
All A3 ALPHA meters provide auditing capabilities that can be used to
indicate potential meter tampering.
The A3 ALPHA meter meets or exceeds requirements of ANSI
standards. The meter precisely measures and displays energy usage
and demand data consistently with the meter class purchased and
through a wide range of the following:
■ current variations
■ voltage variations
■ temperature variations
■ power factor variations
The low current sensor burden may also improve the accuracy of
external current transformers when measuring light loads.
2003.February.28 TM42–2190B 1-5
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1. Introduction A3 ALPHA Meter Technical Manual
Features
Standard Features
The A3 ALPHA meter comes with many options that make it a
powerful meter:
■ fully programmable
■ pre–programmed at the factory
■ wide operating ranges for voltage, current, and temperature
■ complete ANSI C12 protocol capable
■ over 50 displayable instrumentation values including:
■ per phase kW, kVA, and kVAR
■ per phase voltage and voltage angle
■ per phase current and current angle
■ per phase power factor and power factor angle
■ per phase total harmonic distortion for voltage and current
■ per phase total demand distortion for current
■ system kW, kVA, and kVAR
■ average power factor
■ high accuracy internal clock
■ polycarbonate enclosure
■ easily upgradeable through software and optional hardware
■ factory–installed lithium battery (for TOU meters)
■ easy access battery
Advanced Features
There are also some advanced options available. All of these are part
of the main meter board:
■ advanced four–quadrant metering
■ basic load profiling with up to 8 channels
■ instrumentation profiling with up to 32 channels
■ loss compensation
■ power quality monitoring
1-6 TM42–2190B 2003.February.28
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A3 ALPHA Meter Technical Manual 1. Introduction
Option Boards
Some of the option boards available for the A3 ALPHA meter are
indicated below:
■ output relay option board
■ communications
■ internal modem option board
■ external serial communications option board
■ RS232 option board
■ RS485 option board
■ 20mA current loop option board
■ 1 MB extended memory board
2003.February.28 TM42–2190B 1-7
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2. Product Description A3 ALPHA Meter Technical Manual
Physical Description
The physical components of the A3 ALPHA meter consist of the
following:
■ cover assembly
■ electronic assembly
■ base assembly
See Figure 2-5 for an illustration of the A3 ALPHA meter physical
components.
Base assembly
Nameplate
Cover assembly
Optical port
Cover Assembly
The cover assembly of the A3 ALPHA meter is a polycarbonate
housing designed to protect the inner assemblies of the meter. The
ultraviolet (UV) stabilized polycarbonate reflects solar radiation,
resulting in minimized discoloration and reduced internal heating.
The cover has an abrasion–resistant, clear plastic window that allows
the meter LCD to be viewed.
The components on the cover provide the basic user interface to the
meter, such as the optical port and the RESET/ALT button
mechanism. Removing the cover reveals the electronic assembly and
TEST button.
Electronic Assembly
The electronic assembly houses the following components:
■ LCD
Electronic assembly
ALT
RESET
Figure 2-5. Exploded view of the A3 ALPHA meter
■ optical port
■ RESET push button
■ ALT push button
■ magnetic ALT button
■ TEST push button
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A3 ALPHA Meter Technical Manual 2. Product Description
■ nameplate
■ A3 ALPHA main circuit board (contains meter and integral
register electronics with power supply)
The assembly can also accommodate the following optional electronic
components:
■ extended memory option board
■ internal modem option board
■ RS232 communications option board
■ RS485 communications option board
■ 20mA current loop option board
■ external serial communications option board
■ relay option board
See “General Theory of Operation” on page 2-2 for an explanation of
the general operation of the A3 ALPHA meter.
Optical Port
To use Elster Electricity meter support software to read or program
the A3 ALPHA meter through the optical port, an optical probe is
required. This probe connects from the serial port of the computer to
the optical port on the A3 ALPHA meter and provides the required
interface for communications. For information on ordering the optical
probe, contact your local Elster Electricity representative.
Base Assembly
The base assembly contains the following components:
■ base housing
■ battery well for internal modem with outage reporting
■ current and voltage blades
■ current sensing transformers
■ connecting cables for the main meter circuit board
The base assembly also includes a battery well for the internal modem
when supplied with the outage modem reporting features. Table 2-5
shows the available ANSI compatible configurations for a socket–
connected (S–base) or bottom–connected (A–base) A3 ALPHA meter
according to the type of service being metered.
capabilities
2003.February.28 TM42–2190B 2-17
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2. Product Description A3 ALPHA Meter Technical Manual
Tab le 2 -5. A 3 AL PH A me te r av ail ab le w ir in g fo rm s
Meter style Form Te st
Class Elements K
Typ e of s er vi ce
h
Amps
ZAA30xxxxxx 1S 30 200 1 7.2 2–wire single phase
ZAA40xxxxxx 1S 50 320 1 12 2–wire single phase
ZAC30xxxxxx 2S 30 200 1 7.2 3–wire single phase
ZAC40xxxxxx 2S 50 320 1 12 3–wire single phase
ZAA20xxxxxx 3S 2.5 20 1 0.6 2– or 3–wire single phase
ZAC20xxxxxx 4S 2.5 20 1 0.6 3–wire single phase
ZA220xxxxxx 35S
ZA2B0xxxxxx 35A
1
2.5 20 2 1.2 3– or 4–wire delta, 4–wire wye, network
1
2.5 20 2 1.2 3– or 4–wire delta, 4–wire wye, network
ZA530xxxxxx 12S 30 200 2 14.4 3–wire delta, network
ZA540xxxxxx 12S 50 320 2 24 3–wire delta, network
ZA2C0xxxxxx 13A 30 100 2 14.4 3–wire delta, network
ZA820xxxxxx 36S
ZA8B0xxxxxx 36A
ZA320xxxxxx 9S
ZA420xxxxxx 10S
ZA4B0xxxxxx 10A
ZA330xxxxxx 16S
ZA340xxxxxx 16S
2
2.5 20 2½ 1.8 4–wire wye
2
2.5 20 2½ 1.8 4–wire wye
3
2.5 20 3 1.8 4–wire wye or delta
4
2.5 20 3 1.8 4–wire wye or delta
3
2.5 20 3 1.8 4–wire wye or delta
5
30 200 3 21.6 4–wire wye or delta
5
50 320 3 36 4–wire wye or delta
ZA3C0xxxxx 16A 30 100 3 21.6 4–wire wye or delta
1.
Form 35 replaces Form 5 circuit applications. Because the voltage elements share a common point of
reference on one side, the form cannot be used with phase shifting transformers or to totalize separate
single phase services.
2.
Form 36 replaces Form 6 circuit applications. Because the voltage elements share a common point of
reference on one side, this form cannot be used with phase shifting transformers.
3.
Form 9S replaces Form 8S, and Form 10A replaces Form 8A circuit applications.
4.
Form 10S is actually a Form 9S with jumpers across the three common (neutral) connections of the
voltage circuit. This meter style provides a means of replacing a Form 10S meter without requiring
changes to the socket wiring. This form should not be used with phase shifting transformers.
5.
Form 16S replaces Form 14S and 15S, while Form 16A replaces Form 14A and 15A circuit applications.
2-18 TM42–2190B 2003.February.28
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