Probewell MT-1/WT3 User manual

MT-1/WT3
USER GUIDE
HIGH ACCURACY THREE-PHASE
WIRELESS WATTHOUR METER TESTER

MT-1/WT3
User Guide
Version 2.2 –October 2020
IT IS ESSENTIAL THAT THIS INSTRUCTION BOOK BE READ THOROUGHLY BEFORE
PUTTING THIS PRODUCT INTO SERVICE.
© Copyright 2020 by Probewell Lab Inc. Printed in Canada.
All rights reserved, including those to reproduce this manual or parts thereof, in any form
without the express written permission of Probewell Lab Inc.

Probewell Lab Inc.
Page •2
Limited Warranty
Your MT-1/WT3 comes with a two-year hardware warranty. Probewell Lab Inc.
(Probewell) warrants this MT-1/WT3 against defects in material and workmanship
for a period of two (2) years from the date of purchase from Probewell. This warranty
applies only to the original purchaser of the MT-1/WT3 and is not transferable.
All accessories come with a two-year hardware warranty. Probewell warrants all
accessories against defects in material and workmanship for a period of two (2) years
from the date of purchase from Probewell. This warranty applies only to the original
purchaser and is not transferable.
This warranty does not cover any damage caused neither by negligence, non-
authorized modifications, or parts installed without prior written permission from
Probewell.
This warranty does not apply if the product has been damaged by accident, abuse,
misuse, or misapplication, nor as a result of service to the product by anyone other
than Probewell.
PROBEWELL IS NOT RESPONSIBLE FOR ANY LOST PROFITS, LOST SAVINGS OR OTHER
INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE, OR INABILITY
TO USE, OF THIS PRODUCT. THIS INCLUDES DAMAGE TO PROPERTY AND DAMAGES
FOR PERSONAL INJURY. THIS WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES
INCLUDING IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE.
Disclaimer
Probewell Lab Inc., (Probewell) reserves the right to make changes to this document
and the products which it describes without notice. Probewell shall not be liable for
technical or editorial errors or omissions made herein; nor for incidental or
consequential damages resulting from the furnishing, performance, or use of this
material.
Features and specifications are subject to change without notice.

MT-1/WT3 User Guide
Page • 3
Table of contents
Introduction............................................................................................................... 7
MT-1/WT3 Overview ............................................................................................. 7
Description ................................................................................................................ 9
MT-1/WT3 Socket.................................................................................................. 9
Front/Rear View of the Socket ........................................................................ 10
Side View of the Socket ................................................................................... 11
Functioning Theory.............................................................................................. 13
Meter Testing .................................................................................................. 15
Accessories .......................................................................................................... 17
Metercam ........................................................................................................ 17
Optical Pickup.................................................................................................. 18
Meter Adapters ............................................................................................... 19
Operations............................................................................................................... 21
Summary.............................................................................................................. 22
Installation of the Socket..................................................................................... 23
Connecting to the MT-1/WT3.............................................................................. 25
Running the application....................................................................................... 25
Tests available ..................................................................................................... 26
Test Examples...................................................................................................... 27
Example 1: Quick Test - Solid-state 9S meter .................................................. 28
Example 2: Custom Test - Solid-state 9S meter............................................... 30
Example 3: Tracking Test - 12S(N) meter......................................................... 31
Example 4: Custom Test - 2S electromechanical meter................................... 33
Example 5: kW Demand Test –Electromechanical 14S meter ........................ 35
Example 6: Full Test –Solid-state 8S Fitzall meter........................................... 37
Example 7: Four-Quadrant Test –Solid-state 9S meter................................... 39
Example 8: Meter tested in the meter shop.................................................... 41
Appendix A
Specifications........................................................................................................... 43
Appendix B
Compatible Meter Forms......................................................................................... 47
Form 1S................................................................................................................ 48
Form 2S................................................................................................................ 49
Form 3S................................................................................................................ 50
Form 4S................................................................................................................ 51
Form 5S, 35S & 45S Fitzalltm (3 2CT).................................................................. 52
Form 5S, 35S & 45S Fitzalltm (3 2CT 2PT) ........................................................... 53
Form 5S, 35S & 45S Fitzalltm (N 2CT).................................................................... 54
Form 5S, 35S & 45S Fitzalltm (N 2CT 2PT) ............................................................. 55
Form 5S, 35S & 45S Fitzalltm (Y 3CT)..................................................................... 56
Form 5S, 35S & 45S Fitzalltm (Y 3CT 2PT).............................................................. 57
Form 5S, 35S & 45S Fitzalltm (Y 2CT)..................................................................... 58
Form 5S, 35S & 45S Fitzalltm (Y 3CT 2PT).............................................................. 59

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Form 5S, 35S & 45S Fitzalltm (4 3CT 2PT) ........................................................... 60
Form 5S, 35S & 45S Fitzalltm (4 3CT).................................................................. 61
Form 6S (36S, 46S) (Y 3CT)................................................................................... 62
Form 6S (36S, 46S) (Y 3CT 2PT)............................................................................ 63
Form 6S (36S, 46S) Fitzalltm (Y 3CT)...................................................................... 64
Form 6S (36S, 46S) Fitzalltm (Y 3CT 2PT)............................................................... 65
Form 8S (4 3CT)................................................................................................. 66
Form 9S (4 3CT)................................................................................................ 67
Form 9S (Y 3CT) ................................................................................................... 68
Form 9S (Y 3CT 3PT)............................................................................................. 69
Form 12S (25S) (3N)............................................................................................. 70
Form 12S (25S) (3)............................................................................................. 71
Form 14S (4Y)s..................................................................................................... 72
Form 15S (4)...................................................................................................... 73
Form 16S (4Y) ...................................................................................................... 74
Appendix C
Form Configurations................................................................................................ 75
Appendix D
Troubleshooting ...................................................................................................... 77
Appendix E
Parameters for Data Logging Option....................................................................... 79
Appendix F
Customer Service..................................................................................................... 81
Appendix G
Recommendations................................................................................................... 83

MT-1/WT3 User Guide
Page • 5
List of Abbreviations
Abbreviation
Complete Term
A
Ampere
Amp
Ampere
AC
Alternating Current
AP
Access Point
ATK
Accuracy Testing Kit
CFM
Cubic feet per minute
CL
Class
CSV
Comma Separated Value
CT
Current Transformer
DSP
Digital Signal Processor
HL
High Load (Full Load)
Kh
Watthour constant. The number of watthours represented by
one revolution of the disk. Also, called disk constant.
Kt
Test constant. For electronic (no disk) meter, the amount of
energy represented by each calibrated pulse of the LED.
kW
Kilowatt
Lb
Pound
LL
Light Load
NIST
National Institute of Standard and Technology
PF
Power Factor
PPI
Pore per inch
Rev
Revolution, number of revolutions
RMS
Root mean square
TA
Test Ampere
THD
Total Harmonic Distortion
V
Volt
VA
Volt-Ampere
VAC
Volt Alternating Current
VARh
VARhour (Volt Ampere Reactive Hour)
Vdc
Voltage direct current
VT
Voltage Transformer
W
Watt

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Abbreviation
Complete Term
Wh
Watthour
WiFi
Wireless Fidelity
WLAN
Wireless Local Area Network
WWW
World Wide Web
µWh
Micro-Watthour
µVARh
Micro-VARhour

MT-1/WT3 User Guide
Page • 7
Chapter 1
Introduction
The Probewell Lab MT-1/WT3 is a portable three-phase meter tester with built-in
WiFi technology.
MT-1/WT3 Overview
The MT-1/WT3 test socket adapter weighs only 6.4 lb which makes it the ideal tool
for field testing. Within a few minutes, a residential, commercial or industrial
electricity meter can be accurately tested on site by meter shop technicians.
The MT-1/WT3 can be set to test all three phases simultaneously in one step (Quick
Test) or set to do the three phases simultaneously followed by each element
separately (Full Test). The MT-1/WT3 provides measurements for active and reactive
energy with forward and reverse flow testing capability.
The MT-1/WT3 has a built-in three-phase phantom load made of synthesized 50A
current sources and a three-phase electronic standard with a typical accuracy of
±0.02% and a guaranteed accuracy of ±0.05%. It comes with a complete calibration
report certifying measurement accuracy across its entire operating range.
The MT-1/WT3 comes with a shock resistant carrying bag. The bag has individual
compartments for the test socket, the pickups and the User's Guide. There is also
enough space for small accessories such as the magnetic adapter for the optical
pickup, seals, pliers, etc.
Optional: A handheld remote is available for the MT-1/WT3, having a keypad and an
LCD display and weighing only 0.6 lb.

Probewell Lab Inc.
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MT-1/WT3 User Guide
Page • 9
Chapter 2
Description
The first part of this chapter describes the MT-1/WT3 socket. The second part
explains the functioning theory of the tester.
MT-1/WT3 Socket
The MT-1/WT3 socket is cylinder-shaped, designed to be easily inserted in both
ringless and ring-type meter bases. A latch with a quick release mechanism is
available as an option for ring-type meter bases.
The socket contains three 50A synthesized AC current sources to simulate resistive
and reactive loads, a high accuracy three-phase electronic standard and a WiFi
communication controller.
The rear of the socket has six standard fixed tabs with bypasses and two removable
twist-tabs, with twist and lock mechanism. The socket obtains its power directly from
these back tabs and accepts an input voltage from 100 to 600VAC.
The twist-tabs can be placed at 3, 5, 6 and 9 o'clock position as required by the meter
base where the test is conducted. The twist-tab at 3 o'clock can be inserted at two
different positions to hold either forms 6S, 8S, 9S or form 4S. The twist-tab at 9
o'clock can be inserted at two different positions to hold either forms 6S, 8S, 9S or
forms 3S, 4S, 12S. One of the twist-tab can be positioned at 5 o'clock for some 3S or
12S meter bases or positioned at 6 o'clock for 14S, 15S, 16S meter bases. See
Appendix C for all twist-tab configurations.
The front of the socket has seven jaws and five spring loaded contact pistons. The
pistons are actuated by the middle lugs of the meter. A spring contact at 6 o'clock is
also provided for 12S meters. The meter under test is entirely controlled by the
socket. No setup wiring is needed.
The socket has a dead front design for safer operation. The front jaws of the socket
become live only when a meter is inserted. See Appendix A for all technical
specifications.

Probewell Lab Inc.
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Front/Rear View of the Socket
Fig. 2.1 –Front and Rear View of the Socket
Fig. 2.1 shows the removable twist-tabs which do not require any tools to be moved
from a position to another. The above illustration shows only the twist-tab
positioned at 3 and 9 o’clock.

MT-1/WT3 User Guide
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Side View of the Socket
Fig. 2.2 –Side View of the Socket

Probewell Lab Inc.
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Identification
Description
Rear Tabs
The rear tabs connect the socket to the front jaws of the
meter base. The socket gets its power directly from the
meter base (100-600VAC) circuit. The service current
shorting bars (bypasses) are rated for high capacity
amperage.
Removable Tabs
These tabs can be positioned at 3, 5, 6, or 9 o'clock
position as required by the meter base where the test is
conducted. See Appendix C.
Form Selector
In position 1S, 2S, and 15S, the unit is powered from the
two upper tabs. In position 3S, 12S, 14S and 16S, the unit
is powered from the Phase C and the neutral tab. In
position 4S, 6S, 8S and 9S the unit is powered from the 3
and 9 o'clock tabs.
Circuit Breakers
Protection for the MT-1/WT3 and the meter. Two circuit
1A breakers which can be reset by pressing a spring-
loaded button.
Power Switch
Socket's main power on/off switch.
Front Jaws
The front jaws are controlled by internal relays allowing
to test meters. The front jaws become live only when a
meter is inserted. The voltage on the front jaws is current
limited for additional protection.
Pistons
These are actuated by the small lugs on the back of the
meter when inserted for testing.
I/O Connector
Isolated full-duplex communication port. It also provides
an isolated and current limited low voltage supply for the
accessories (optical pickup and metercam) and the
optional handheld remote control.
QR Code Sticker
The QR code sticker contains the access point
information to be scanned for a mobile device as well as
the MAC address.
LED
Socket Status Indicator.
Magnetic Switch
Switch for any manual entry using a magnet.
Air Vent(1)
Warm air exit. A 5 CFM miniature fan forces air
circulation inside the socket.
Air Inlet(1)
Cool air input. Filtered through polyurethane foam filter.
(1) Do not block air circulation. Keep away from direct heat or flame.

MT-1/WT3 User Guide
Page • 13
Functioning Theory
MT-1/WT3 applies a load to the meter under test, then measures exactly the
quantity of energy that passes through the meter. After a predetermined number of
disk revolutions, or a minimum time in the case of a solid-state meter, the test will
end, and the application (Probewell Connect) will display the difference between the
meter and the MT-1/WT3's internal electronic standard.
Current Applied to the Meter
The current applied to the meter under test is achieved by three independents built-
in 50A synthesized AC current sources. The current level is adjustable and regulated.
The current sources allow to simulate loads at unity and 0.5 lagging power factor.
They are isolated and form three independent current loads in closed-link
arrangement. This configuration allows to check a meter without the need to open
the potential link of the meter and no wiring setup is necessary.
Voltage Applied to the Meter
The voltage applied to the front jaws is derived from the meter base circuit. For
safety reasons, the voltage is applied to the front jaws only when a meter is inserted.
The voltage is also current limited.
The front jaws of the MT-1/WT3 are controlled by internal relays allowing to test
self-contained and CT rated three-phase and single-phase watthour meter form
configurations without wiring setup.
Built-in Electronic Standard
The built-in electronic standard in the MT-1/WT3 has an exceptional accuracy thanks
to the use of electronic transducers developed by Probewell. These transducers have
an exceptional long-term stability and linearity and are not affected by temperature.
The electronic standard does not contain any potentiometers or other types of screw
adjustment that could become unstable with time. It uses digital technology to
ensure a maximum of reliability over time. A DSP processor measures and calculates
the exact energy, active or reactive, that passes through the meter. This technology
has the advantage of obtaining a more compact and lightweight electronic standard
while minimizing electronic components.
Accuracy Test
The MT-1/WT3's electronic standard is calibrated using a primary standard traceable
to NIST and comes with a complete calibration report certifying measurement
accuracy on both Wh and VARh scales over its entire operating range. Accuracy test
on MT-1/WT3 can be done in your own laboratory using:

Probewell Lab Inc.
Page •14
•An electronic reference standard traceable to NIST. The electronic
standard must have at least 1 isolated current input port of a minimum
capacity of 50A with auto ranging capability and a typical precision of
0.01% or better;
•A laboratory stabilized and isolated AC power source with fundamental
waveform selectable 120V or 240V, 60Hz, rated at least 150VA;
•The Accuracy Test Kit (ATK-3) for three-phase testers.
For more information on socket accuracy test please refer to the ATK and Probewell
Connect for WT series documentations.

MT-1/WT3 User Guide
Page • 15
Meter Testing
Tests performed with a pickup accessory (Optical or Metercam)
Five different tests can be done with optical pickups: Quick, Full, Custom, Four-
Quadrant (WH) and Four-Quadrant (VARH) Test.
Quick Test, Full Test, Four-Quadrant (WH) and Four-Quadrant (VARH) Test are made
up of a predetermined sequence of consecutive steps and tests, all of which are done
in one operation. The sequence is programmable and can be modified through the
Settings tab. By default, the sequence includes one test point with each of the loads:
HL, PF and LL.
In Quick Test,the three phases (ABC) are tested simultaneously in one step.
In Full Test,a Quick Test is performed followed by each phase separately (A, B, and
C). In the Settings tab, there is an option to remove the PF and/or LL for each single
element test.
In Four-Quadrant (WH) Test, the equivalent of a Quick Test is done at various phase
lags between Voltage and Current. This is meant to test the operation of the meter
in all four quadrants of the power vector diagram. For this test, the device expects
the meter to pulse on WH units.
In Four-Quadrant (VARH)Test, the equivalent of a Quick Test is done at various phase
lags between Voltage and Current. This is meant to test the operation of the meter
in all four quadrants of the power vector diagram. For this test, the device expects
the meter to pulse on VARH units.
Please note that with single-phase meters, only the Quick Test, Four-Quadrant (WH)
and Four-Quadrant (VARH) test will be activated as there is no Full Test for single-
phase meters.
Custom Test consists in choosing one of the three loads to apply to the meter: HL, PF
or LL. The disk revolutions or pulses are counted automatically by the pickup. No
critical timing is required to start a test. The test ends automatically.
When testing a three-phase meter, you can also choose to apply the load on all
phases (ABC) at the same time or on each phase individually (A, B or C). The phase
selection is done by selecting the appropriate phase (A, B, C, or A+B+C) in the Select
Active Phase drop down window.
Tests performed without a pickup accessory (Optical or Metercam)
Manual Test is used when the operator counts the disk revolutions manually. A
magnet is used to start and end the test manually by applying it to the side of the
socket (see figure 2.2). The operator can set his own parameters for conducting a
test, such as the number of revolutions and the load to be applied. The load can be
switched dynamically during the test.

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Please note that without the help of a pickup, if the operator signals the start or the
end of a test too soon or too late using the magnet (magnetic switch), the number
of disk revolutions (a whole number without fraction) might not be accurate and will
affect the precision of the test.
Tracking Test is like the Manual Test except the socket counts the number of
revolutions and displays them on your wireless device. The count is based on the
selected Kh of the meter and the cumulative watthours recorded by the MT-1/WT3
and not the physical count of the disk revolutions. A magnet can be used to start and
end the test.
kW Demand Test allows the operator to perform a kW demand test and the test is
calculated using the following formula:
kW = kWh x 60/T
Where T = Demand interval length in minutes
Note: With solid-state metering, conducting energy and demand tests may be
considered redundant since they are both results of the same measurement.
Set up the meter for a kW demand test following the manufacturer's instructions.
Please note that the kW demand test method varies between manufacturer's
reference technical guide for instructions.
Line monitor Test analyzes the input voltage to determine statistically the line
voltage, frequency fluctuations and its harmonic content (THD) up to the 32nd order.
KYZTest is used to verify the KYZ or KY meter’s output pulses.

MT-1/WT3 User Guide
Page • 17
Accessories
Metercam
The Metercam is used with an electromechanical meter (rotating disk). It is a digital
disk sensor without the many drawbacks found on usual photoelectric sensors, such
as difficulty to align properly and sensitivity to light. With the Metercam, no
alignment is necessary since it detects and picks up the disk by itself. Another feature
is its electronic shutter that makes it insensitive to light variations including bright
sunlight.
The Metercam is built around a miniature digital camera with a ½" field view
combined with a RISC processor that detects the position of the meter disk and locks
automatically on the reference point (black flag).
The Metercam is mounted on four suction cups installed directly on its backside.
For a good and lengthy hold, lightly wet the inside of the suction cups, especially
when field testing in colder weather. Also, keep the inside of the suction cups clean.
Fig. 2.4 –Metercam
Note: For electromechanical meters with a hidden disk, a side-mount Metercam is
available.

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Optical Pickup
The Optical Pickup is used with solid-state meters. It is mounted with a suction cup
or integrated in a magnetic head that detects infrared light pulses from solid-state
meters. The Optical Pickup uses edge triggering for less sensitivity to changes. On
the top of the head of the pickup, there is a pulse indicator in the form of a visible
red led that flashes when pulses are being received.
Fig. 2.5a –Optical Pickup
Fig. 2.5b –Magnetic Optical Pickup
Adapters
The Focus Adapter is used with the
Optical Pickup for meters with a
protuberant shape over the test pulse.
The Magnetic Adapter is used to install
the suction cup of the Optical Pickup
on meters with a metallic port. Can also
be used a magnet for the magnetic
switch.

MT-1/WT3 User Guide
Page • 19
Meter Adapters
Sensus 3S: This adapter is used to test Sensus’3S meter, without this adapter the
meter will be damaged.
Class 320: This adapter is used to test 4S and 12S meter in a CL320 meter base,
without this adapter the WT3 will not be insertable in the meter base.