ASTM E929-83(2005)
(Test Method)Standard Test Method for Measuring Electrical Energy Requirements of Processing Equipment
Standard Test Method for Measuring Electrical Energy Requirements of Processing Equipment
SCOPE
1.1 This test method covers the determination of the energy and power requirements of processing equipment using an electrical metering system.
1.2 This test method can be used to measure energy and power requirements of processing equipment driven by an electrical motor operating on alternating current.
1.3 This test method includes instructions for installation and checkout of the energy metering system, procedures for measuring and recording energy usage, and methods for calculating the average gross power, average freewheeling power, and average net power requirements of processing equipment.
This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For hazard statements, see Section .
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Designation:E929–83 (Reapproved 2005)
Standard Test Method for
Measuring Electrical Energy Requirements of Processing
Equipment
This standard is issued under the fixed designation E929; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope moving material, changing its characteristics, or separating it
into different streams).
1.1 This test method covers the determination of the energy
2.7 net power—the difference between gross power and
and power requirements of processing equipment using an
freewheeling power; net power is the power required for
electrical metering system.
processing.
1.2 This test method can be used to measure energy and
2.8 specific energy— energy consumption expressed on the
power requirements of processing equipment driven by an
basis of unit mass of throughput.
electrical motor operating on alternating current.
2.9 unloaded condition—equipment not doing processing
1.3 This test method includes instructions for installation
work (for example, moving, changing the characteristics of, or
and checkout of the energy metering system, procedures for
separating materials), but operating in a freewheeling, or
measuring and recording energy usage, and methods for
idling, condition.
calculating the average gross power, average freewheeling
power, and average net power requirements of processing
3. Summary of Test Method
equipment.
3.1 An electrical metering system is installed and checked.
1.4 This standard does not purport to address all of the
3.2 Themeteringinstrumentationandprocessingequipment
safety concerns, if any, associated with its use. It is the
is allowed to warmup.
responsibility of the user of this standard to establish appro-
3.3 Usingtheelectricalmeteringsystem,theenergyusedby
priate safety and health practices and determine the applica-
the processing equipment under no-load and loaded conditions
bility of regulatory limitations prior to use. For hazard state-
is measured and recorded.
ments, see Section 6.
3.4 The average gross power, average freewheeling power,
2. Terminology Definitions and average net power required by the equipment is calculated.
2.1 electrical metering system—a system composed of cur-
4. Significance and Use
rent and potential transformers and a wattmeter electrically
4.1 Energy usage and power requirements of processing
connected in such a manner so as to measure the energy usage
equipment are important from the standpoint of determining if
of a piece of equipment driven by an electric motor.
equipment is operating within specification and meeting per-
2.2 freewheeling condition—a piece of equipment under an
formance criteria.
unloaded condition wherein the electrical energy is dissipated
4.2 Having determined the energy usage and power require-
due to friction and windage.
ments of the processing equipment using this method, specific
2.3 freewheeling power—power requirement of a piece of
energy may be calculated, with the use of system throughput,
equipment under unloaded, or freewheeling, conditions.
and used as one criterion to compare the performance of
2.4 gross energy— energy usage of a piece of equipment
similar pieces of equipment operating under similar operating
operating under loaded conditions as measured using an
conditions.
electrical metering system.
4.3 Measurements of energy usage can be used for the
2.5 gross power— power requirement of a piece of equip-
purposeofidentifyinginefficientelectricalmotorsandprocess-
ment under loaded conditions.
ing equipment.
2.6 loaded condition— equipment doing processing work
on solids, liquids, or gases, or all of these, (for example,
5. Apparatus
5.1 Calibrated Watthour Meter.
This test method is under the jurisdiction of ASTM Committee D34 on Waste
5.2 Volt-Ammeter.
Management and is the direct responsibility of Subcommittee D34.03 onTreatment,
5.3 Stopwatch, accurate to 0.1 s.
Recovery and Reuse.
5.4 Incandescent Lamps, for use as a known load.
Current edition approved Feb. 1, 2005. Published March 2005. Originally
approved in 1983. Last previous edition approved in 1999 as E929-83(1999). DOI: 5.5 Current Transformers (CTs).
10.1520/E0929-83R05.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E929–83 (2005)
Watthour Meter Serial No. Type Class K Accuracy Date Calibrated
h
Current Transformer Serial No. Type Ratio Accuracy Class Date Calibrated
Potential Transformer Serial No. Type Ratio Accuracy Class Date Calibrated
FIG. 1 Electrical Metering System Installation Form
5.6 Potential (Voltage) Transformers (PTs). 8.1.1.1 Self-contained single phase watthour meter can be
used when the load is less than 48 kVA.
6. Hazards
8.1.1.2 Self-contained polyphase meters can be used when
the load is less than 96 kVA (except 480 V delta).
6.1 When installing metering equipment always de-energize
8.1.1.3 Above 48 or 96 kVA, respectively, for single and
the load side of the processing equipment by locking out the
main switch on the electrical control panel. polyphase loads, use transformer type watthour meters.
6.2 Dangerous high voltage results from open current trans- 8.1.2 For any meter installation, do not exceed the meter’s
formersecondaries.Therefore,toavoidequipmentdamageand overload capability listed as follows:
electrical shock, use circuit-closing devices or equipment to
8.1.2.1 Class 10—Nominal 2.5-A meter, 10-A overload
short circuit the secondaries of current transformers. capability.
6.3 Always observe the polarity markings of current and
8.1.2.2 Class 20—Nominal 2.5-A meter, 20-A overload
potential transformers during their installations to ensure
capability.
proper connection of the metering equipment. These polarity
8.1.2.3 Class 60—Nominal 15-A meter, 60-A overload
markings are usually denoted on the transformers as white
capability.
dots, blocks, or “HX” marks.
8.1.2.4 Class 100—Nominal 15-A meter, 100-A overload
6.4 Closely observe polarities, and check connections of
capability.
instrument transformers to the watthour meter.
8.1.2.5 Class 200—Nominal 30-A meter, 200-A overload
capability.
7. Equipment Calibration
8.1.2.6 Class 320—Nominal 50-A meter, 320-A overload
7.1 Calibrate all meters and instrument transformers used
capability.
for energy measurements in accordance with standard practice
8.1.3 Instrument Transformers—For meter installations re-
, , ,
2 3 4 5
of calibration. The accuracy of the meters and trans
quiring instrument transformers (that is, when the primary
formers shall be duly noted on the Electrical Metering Service
current or voltage, or both, exceed the operating specifications
Installation Form, see Fig. 1.
of the watthour meter), use current and potential (voltage)
transformers. Select current and potential transformers with an
8. Procedure
accuracy class rating of 0.3 (0.3 %) and compatibility with the
8.1 Meter Installation:
primary electrical service. If transformers with an accuracy
8.1.1 For the piece of equipment to be tested, determine the
class of 0.3 are not available, substitute another accuracy class
type of electrical service (for example, single-phase two-wire,
and note on the Electrical Metering System Installation Form
three-phase three-wire), voltage requirements, full load power,
(Fig. 1).
and current rating of the motor from the motor nameplate or
8.1.4 Current Transformers—Calculate the current trans-
manufacturer’s specifications. For the purpose of meter selec-
former ratio (CTR) using the following definition.
tion and installation, it can be assumed that 1 hp = 1 kW = 1
CTR 5 Primary Current/Watthour Meter Nominal Current Rating
kVA. Select the metering system that is compatible with the
(1)
type of electrical service and with the load on the motor.
Generally, current transformer ratios are denoted such that
the secondary current will be 5 amperes when rated amperes
are flowing in the primary circuit.
Meter and Instrument Transformer Application Guide , 5th Edition, Westing-
8.1.5 Potential Transformers — Potential transformers are
house Electric Company, Raleigh, NC.
Metermen’s Handbook, Duncan Electric Company, Lafayette, IN, No. 5M,
used with watthour meters where the primary circuit voltage
April 1976.
exceeds the rating of the meter, generally above 480 V and
Electrical Metermen’s Handbook, Edison Electric Institute, New York, NY.
frequently above 240 V. The potential transformer ratio (PTR)
Guide for Installing General Electric Watthour Meters , General Electric
Company, Somersworth, NH, April 1976. can be calculated using the following definition.
E929–83 (2005)
PTR 5 Primary Voltage/Watthour Meter Nominal Voltage Rating
of the watthour meter while operating the processing equip-
(2)
ment under loaded conditions for a suitable measuring period.
Asuitable measuring period consists of a time span that is long
8.1.6 Phase relations will be retained if the polarity mark-
enough to attain at least one disk revolution or at least one
ings are observed and the current in the potential circuit is
complete rotation of the least significant register dial, which-
consideredtoflowinontheprimaryterminalpolaritymarkand
ever applies to the particular test situation.
out on the corresponding secondary terminal polarity mark.
8.1.7 The Electrical Metering Service Installation Form
8.3.5 An Energy Measurement Data Sheet for recording the
(Fig. 1) is recommended for documenting the equipment used
measured data from the tests conducted under loaded condi-
for the test.
tions is given in
Fig. 2.The calculations for determining power
8.1.8 Mount instrument transformers and watthour meters
demand under loaded conditions are described in Section 9.
in an upright position and in a area free from heavy vibration.
8.3.6 Alternative Procedure for Constant Load Power
8.2 Checking Meter Installation:
Measurements—If the processing equipment exhibits a con-
8.2.1 Check meter installations for correct connections as
stant load as evidenced by power fluctuations of less than
soon as the wiring is completed. For installation of self-
610 % of the average reading (that is, as may be the case for
contained watthour meters this is comparatively simple. It is
a conveyor or blower, etc.), a clamp-on wattmeter, an analog
only necessary to see that line and load wires, and potential
wattmeter, or recording wattmeter can be used to measure
taps where required, are connected to the proper points. A
power if the metering equipment and electrical service can be
quick check on the operation under load conditions may be
made compatible with one another. For this procedure, power
made to see that the meter is rotating in the proper direction
measurements for both unloaded (freewheeling) and loaded
and at approximately the right speed.
conditions should be made in sufficient numbers so that a
8.2.2 Where instrument transformers are used, the installa-
reliable average reading can be calculated. The power require-
tion is more liable to incorrect connections and should,
ment is read directly from the instrument. The measurements
therefore, be checked carefully. It is possible to have incorrect
may be recorded on the Gross and Net Power Data Sheet, Fig.
registration even with proper connections, due to a wrong
3.
transformer polarity marking, a reversed meter coil, incorrect
transformer ratio marking, etc. It is generally not possible to
9. Calculation
completely check all of these items in the field; however, by
making several of the tests listed in Annex A1, it will be 9.1 Average Freewheeling Power Requirements:
possible to determine most of the inconsistencies or incorrect
9.1.1 Calculate freewheeling power ( P ), in kilowatts, as
fw
connections that might occur.
follows:
8.3 Measurements:
P 5 600 ~Kh!~CTR!~PTR!/t (3)
fw
8.3.1 After installation and check-out of the energy meter-
ing equipment, measure and record the energy used by the where:
equipment under no-load and loaded conditions in order to Kh = disk constant of the watthour meter (kWh/disk
revolution),
determine the average gross and freewheel power requirements
CTR = current transformer ratio,
of the equipment.
PTR = potential transformer ratio, and
8.3.2 Determine the average freewheeling power of the
t = time duration for 10 disk revolutions (minutes).
equipment to be tested by measuring the energy usage of the
9.1.2 Average the three initial freewheeling power measure-
motor under no-load conditions over a specified time interval.
ments and the three final measurements to give the average
After a suitable warm-up period, time ten disk revolutions to
¯
establish the freewheel energy usage at the beginning and end initial freewheeling power ( P ) and final freewheeling power
fw
i
¯ ¯ ¯
of the test. Prior to taking the first measurement for determin- ( P ).Then average the average values ( P and P ) and use
fw fw fw
f i f
¯
ing the freewheel energy usage, take two preliminary free-
as the average freewheeling power requirement P of the
fw
wheel energy measurements (10 disk revolutions) approxi- equipment corresponding to the interval of gross energy
mately 5 min apart. If the preliminary readings differ by more
measurement. Record the average value for the freewheeling
than 10 % or more, extend the warm-up period until two
power in the column titled “Average Freewheel Power” of the
consecutive preliminary measurements fall within 10 % of one
Gross and Net Power Data Sheet (see Fig. 3).
another.
¯
9.1.3 Calculate average initial freewheel power ( P )as
fw
i
8.3.3 After the suitable warm-up period, take and record
follows:
three initial disk timings of ten revolutions each. Likewise,
¯
P 5 ~P 1 P 1 P !/3 (4)
fw fw fw fw
i a b c
aftertheconclusionoftheloadtests,takeandrecordthreefinal
disk timings of ten revolutions each. An Energy Measurement
where:
Data Sheet for recording the freewheeling energy measure-
P ,P , and P are the three initial freewheeling power
fw fw fw
a b c
ments is given in Fig. 2. The freewheeling power calculations
measurements.
are described in Section 9.
¯
9.1.4 Calculate average final freewheel power ( P )as
fw
f
8.3.4 Determine the gross energy usage ( E ) of the equip-
g
follows:
ment undergoing testing by calculating the difference in the
¯
P 5 ~P 1 P 1 P !/3 (5)
register readings or by counting the number of disk revolutions fw fw fw fw
f x y z
E929–83 (2005)
CTR: ___ PTR: ___
Watthour Meter Reading
Test No. Time Interval (Min) Disk Revolutions (n) Kh (kWh/re
...
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