KM-90A WATTHOUR METER TEST SYSTEM
Functional Description and Specifications
A.
General
The test system shall:
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B.
include a built-in analyzer/counter dedicated to the purpose of testing
watthour meter parameters;
allow test sequence setup from an operator programmable menu;
provide a "semi-automatic" testing mode wherein the Full Load, Power
Factor, and Light Load tests on a meter are performed automatically, without
operator intervention;
allow set up by form switch and front panel patch leads;
allow closed-link testing of single-phase and polyphase meters;
provide overall system accuracy of ±0.1% at unity and 50% power factor;
use a pneumatically (air) operated test socket which remains closed upon
loss of power or air.
Test Requirements
1.
Tests Performed
a.
Watthour
As Found and As Left results shall be stored separately. Each can
be separately recalled to the display, printed out, or sent to a
computer or other peripheral device via an RS-232 port (or parallel
port).
b.
KYZ (Pulse Initiators)
Pulse initiator testing can be performed in either the "pulses" or
"revolutions" mode. Pulses/revolution and its reciprocal shall be
calculated and displayed. Additionally, KY and KZ counts shall be
displayed.
c.
Demand Meter Testing
Demand testing shall be done by either a time interval (0.1 to 99.9
minutes) or by a number of watthours (as measured by the watthour
standard). The unit shall display the average KW applied, the disk
revolutions, measured watthours, and the time of the test to the
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nearest tenth of a minute.
d.
Creep
The system shall allow application of test voltage (without test
current) for creep testing.
e.
Reference Standard
The system shall be capable of testing external pulse producing
standards (open collector output).
2.
Meters Tested
The system shall test all socket base meters–ANSI (American National
Standards Institute) forms 1 through 16 (excluding 11), 19, 20, 21, 24, 26,
and 29. All meters shall be tested with their links closed.
3.
Other Test Characteristics
a.
Semi-automatic Sequencing
This feature shall allow the test system to automatically sequence
through Full Load, Power Factor, and Light Load tests without
operator intervention.
b.
Weighted Average
The operator can choose to display the weighted average–which is
calculated as [(4FL)+(1LL)]5. It shall be possible to use the
following formula for polyphase meters: [(4FL)+(2PF)+(1LL)]7.
c.
Statistical Calculations
The system shall automatically calculate and store the arithmetic
mean (bar-x) and standard deviation (sigma) for a group of up to 999
meters. It shall be possible to display the accumulated results on a
batch of meters at any time.
d.
Repeat Tests
The system shall allow automatic repeating of a test on a given
meter up to 999 times. The results of each test can be automatically
printed.
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e.
Limits
It shall be possible to set limits for series test results and for individual element balance. Out of limit results shall be indicated by flashing the result in the display.
f.
Test Sequence
A custom test sequence can be programmed into the unit. The unit
will prompt the operator for the next test in the sequence.
g.
Display of Test Results
Test results shall be displayable as percent registration or percent
error.
h.
Calibration
Means shall be provided to calibrate the system against an external
reference standard (SC-60, SC-10V, SC-30, RM-11, RM-10, RM-16,
A-7, A-6, etc.). Separate calibration factors can be entered for each
of the twelve possible watthour tests (Series Full Load, Series Power
Factor, ..., Right Light Load).
i.
Test Voltage
Test voltages of 69, 120, 208, 240, 277, and 480 volts shall be
selectable. The voltage can be continuously varied from 50% to
110% of the selected value. The voltage shall be ramped from zero
to the selected value when turned on, and ramped from the selected
value to zero when turned off. The voltage shall be regulated to
within ±1% for an input swing of ±10%. Waveform distortion shall
not exceed 0.5%. The voltage shall be displayed on a digital meter
in percent of full scale.
j.
Test Current
Full load test currents of 2.5, 5, 10, 15, 20 ,25, 30, and 50 amperes
shall be selectable. The respective light load values (10%) are
automatically selected. The current can be continuously varied from
50% to 110% of the selected value. The current shall be ramped
from zero to the selected value when turned on, and ramped from
the selected value to zero when turned off. The current shall be
regulated to within ±1% for an input swing of ±10%. Waveform
distortion shall not exceed 0.5%. The current shall be displayed on a
digital meter in percent of full scale.
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C.
Operation
1.
Meter Test Setup
A panel-mounted form switch shall be provided to set up the system for
testing different form number meters. The form switch shall be able to be
used for patching the system for ANSI form numbers 1 through 16
(excluding 7 and 11).
In addition to the form switch, a voltage and current patch panel shall be
provided on the front of the system in order to configure it to test meters
which are not covered by the form switch.
2.
Optics
Means to count disk revolutions using the reflect method shall be provided.
Visual and audible indications of each revolution shall be provided.
3.
Calculation of Test Result
The counter shall automatically calculate and display the test result. Any
user entered calibration factors shall be automatically included in the test
result.
4.
Protection Circuitry
The system shall include circuitry to protect for inadvertent switch changes
with power applied to a meter-under-test. The circuitry shall ramp down the
voltage and/or current, check for an overload condition, and, if none is
detected, ramp up the voltage and/or current.
The system shall include circuitry to detect voltage and current overloads.
Audible and visual alarms shall be provided to alert the operator of an overload condition.
5.
System Setup
The counter shall be capable of comparing the system voltage and current
switch settings with any bar code entries and shall indicate an error if the
system is not set up correctly.
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D.
Input/Output
1.
I/O Ports
Two serial (RS-232C) ports shall be provided to:
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export test results to an external computer, and
import data from a bar code reader.
One parallel (Centronics) port shall be provided to export data to a printer.
E.
Miscellaneous
1.
Input Power
Input power requirements shall be 120 VAC (±10%), 60 Hz., single-phase at
500 VA maximum.
A separate circuit breaker shall be provided to energize the watthour
standard independently of the main system on/off switch.
2.
Dimensions
The console shall measure approximately 32.4 in. (82.3 cm) Wide by 18.2
in. (46.2 cm) High by 14.3 in. (36.3 cm) Deep.
3.
Weight
The system shall weigh less than 150 lbs. (68 kg.).
4.
Environmental
Operating temperature range: 55 to 90 F. (13 to 32 C.)
5.
Portability
The system shall be able to be placed in a van for field use. The system
shall be capable of being powered by a portable generator.
6.
Auxiliary Outlets
The system shall be provided with two 120 volt, 3-wire grounded outlets for
auxiliary use.
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7.
Reference Standard
The system shall contain a built-in solid-state reference standard.
8.
Generation of Voltage and Current
The voltage and current applied to the meter-under-test shall be
electronically generated and monitored.
F.
Options
1.
Printer
The printer shall be an Epson FX-series or equivalent.
2.
Varhour Meter Testing
It shall be possible to purchase the test system with a varhour standard for
the purpose of testing varhour meters.
3.
Bar Code Hardware
The bar code hardware shall be a Symbol Technologies Reader and Wand.
The bar code software shall be included with the standard system.
4.
A-Base Adapter
This adapter shall allow testing of bottom-connected single-phase and
network meters.
5.
P-Base Adapter
This adapter shall allow testing of bottom-connected polyphase meters.
6.
Solid-State Meter Probe
It shall be possible to purchase a probe which allows testing of solid-state
(electronic) watthour meters by sensing the meter's infrared pulse output.
The circuitry required to use this probe shall be included with the standard
test system.
7.
Desk
It shall be possible to purchase the test system mounted on a desk.
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