Vanguard Accu-Trans User Manual

OPERATING INSTRUCTIONS

for the

ACCU-TRANS™

TRANSFORMER-WINDING

RESISTANCE METER

Series II

Part Number VIC-8000-S2

Vanguard Instruments Company

1710 Grevillea Court
Ontario, California 91761

TEL: [phone] July 2001
FAX: [phone] Rev 0

Accu-Trans Operating Procedures

SAFETY SUMMARY

The following safety precautions must be
observed during all phases of test set-up, test
hookups, testing, and test-lead disconnects.

Do Not Service or Test Alone

Do not perform test procedures or service
unless another person is also present who is
capable of rendering aid and resuscitation.

Avoid Contact with High Voltage

Because electric utility station environments
contain high voltages and currents, there’s
always the possibility of personal contact with
an unexpected lethal voltages generated by
magnetically induced and/or electrostatic
leakage from nearby live circuitry. When test
units are connected to de-energized ("dead")
lines, regardless of how short these lines may
be, always discharge the lines before
attaching test lead. Because of the possibly
deadly consequences of physical contact with
such lines, engineers and technicians must
always treat electrical equipment and hookups
as though a lethal condition will eventually
occur. Therefore, no matter how unlikely it
may be, never assume anything about the
safety of any test setup.
Ensure the safety of personal by checking

first-hand to eliminate every possible hazard!

Avoid Contact With High-Voltage “Kicks”

Any transformer with many windings turns
and an iron core supports induced magnetic
fields, such that even low-level test currents
produce a magnetic field that, if interrupted,

can produce a high-voltage spike capable of
causing severe injury or death. Accordingly,
its important for personnel safety that test
leads be securely attached to the transformer
terminals to prevent their being accidentally
disconnected during testing. All personnel
are warned to stand clear of the transformer
during all testing. Test technicians should
always ensure that all non-technical personnel
(who may not understand the hazards) be
required to stand clear of all transformers and
equipment during all phases of transformer
testing.

Do Not Modify Test Equipment

Because of the added risk of introducing
additional or unknown hazards, do not install
substitute parts or perform any unauthorized
modification to the Accu-Trans. To ensure all
designed safety features are maintained, it is
recommended that all Accu-Trans repairs be
performed at Vanguard Instruments Co. or by
an authorized repair-service. Unauthorized
equipment modifications can create safety
hazards and will void the Accu-Trans
warranty.

Follow Exact Operating Procedures

Any deviation from the operating
procedures described in this manual may
create one or more safety hazards, damage
the unit or cause test result errors; Vanguard
Instruments Co. assumes no liability for
unsafe or improper use of the Accu-Trans.

i

Accu-Trans Operating Procedures

1

Table of Contents

SAFETY SUMMARY................................................................................................................. I

1.0 INTRODUCTION...................................................................................................................3

1.1 APPLICABILITY................................................................................................................3

1.2 SUPERSEDURE NOTICE..................................................................................................3

1.3 GENERAL DESCRIPTION................................................................................................3

1.4 FUNCTIONAL DES CRIPTION.........................................................................................3

1.5 FURNISHED ACCESSORIES ...........................................................................................3

2.0 ACCU-TRANS SPECIFICATIONS.......................................................................................4

3.0 CONTROLS and INDICATORS ............................................................................................5

4.0 PRETEST SETUP ...................................................................................................................7

4.1 OPERATING VOLTAGES.................................................................................................7

4.2 ACCU-TRANS LCD CONTRAST CONTROL.................................................................8

4.3 ACCU-TRANS PRINTER PAPER CONTROL.................................................................8

5.0 ACCU-TRANS PRINTER PAPER.........................................................................................8

6.0 OPERATING PROCEDURES................................................................................................8

6.1 GENERAL PROCEDURES................................................................................................8

6.2 STEP-BY-STEP PROCEDURES AT START-UP MENU..............................................10

6.2.1 START-UP MENU:.......................................................................................................10

6.2.2 TEST TRANSFORM ER PROCEDURE.......................................................................10

6.3 SETUP MENU:..................................................................................................................11

6.3.1 TRANSFORMER ID ENTRIES:..................................................................................12

6.3.2 REVIEW TEST RECORDS PROCEDURE .................................................................13

6.3.3 RESTORE RECORDING PROCEDURES ..................................................................14

6.3.4 PRINTING TEST-RECORD DIRECTORY.................................................................15

6.3.5. ERASE RECORDING PROCEDURE..........................................................................17

6.3.6 ENABLING COMPUTER INTERFACE.....................................................................18

6.3.7 SETTING DATE AND TIME.......................................................................................18

6.3.8 ENABLE PASSIVE TEST MODE ...............................................................................19

6.3.9 VOLTAGE REGULATOR TEST.................................................................................19

Accu-Trans Operating Procedures

2

Table of Figure

Figure 1.0 Accu-Trans Controls and Indicators............................................................................5

Figure 2.0 90 to 130Vac Jumper Setting.......................................................................................7

Figure 3.0 210 to 240Vac Jumper Setting.....................................................................................7

Figure 4.0 Summary of Step-by-Step Accu-Trans Operat ion.......................................................9

Figure 5.0 Typical Test Report Printout......................................................................................12

Figure 6.0 Typical Record Directory Printout .............................................................................17

Accu-Trans Operating Procedures

3

1.0 INTRODUCTION

1.1 Applicability

This manual applies to a second-generation
Accu-Trans™ (Series II, henceforth, called
the Accu-Trans), part number VIC-80000­S2 manufactured by the Vanguard
Instruments Co. A prior manual supports a
first generation Accu-Trans (i.e., a Series I
configuration).

1.2 Supersedure Notice

This Operator’s manual is the basic issue for
the Accu-Trans and does not supersede any
previously published manual.

1.3 General Description

Vanguard Instruments Company produces
the Accu-Trans, a microprocessor-controlled
winding resistance meter that measures low
resistances of a transformer’s inductive
windings, in a range from 1 micro-ohm to
200 ohms with very high accuracy. This
instrument can also measure any low
milliohm resistance (e.g., the contact
resistance of a circuit breaker).
This Accu-Trans is simple-to-use; it features
keypad controls and an alpha/numeric
display of the measured resistance, test
current, and operator-entered test parameters
and identifying data.
The Accu-Trans uses a 48-volt dc power
supply and a special current-regulator to
quickly measure transformer-winding
resistances. A typical single- phase 400MVA

transformer winding resistance can be
measured in less than 3 minutes. To ensure

operator safety, the Accu-Trans
automatically discharges the energy stored
in the transformer at the end of each test.
A built-in thermal printer prints test results
on 2.5-inch-wide thermal paper. Resistance
and test current display on a 4-line by 20­character, back lighted LCD. Up to 63
records (96 readings each) can be stored in
the Accu-Trans FLASH EEPROM. The
user can recall stored reports for printing. A
RS-232C serial interface port is provided for

diagnostic testing and down loading test
records.
The Accu-Trans is field-portable, rugged; it
features simple, easy operation by first-time
users with little training.

1.4 Functional Description

The Accu-Trans’s operation is based on the
electrical relationships described by Ohm’s
law: R=V/I, where I is a known current and
V is the dc voltage measured across the
unknown resistance (typically, a circuit­breaker’s contacts). The value of the
unknown resistance under test is the direct
function of the measured voltage divided by
the current and being calculated by the
microprocessor. Resistance reading is then
displayed on a back-lighted 4 line by 20
character LCD.
The Accu-Trans’ 48V dc power supply
applies up to 2 amperes test current to the
device under test. Accu-Trans voltmeter test
leads are run separately from the current­bearing test leads to the resistive load; thus,
voltages are measured at the terminals of the
resistance being measured, eliminating error
from the I•R voltage drop in the test current
cables. The Accu-Trans makes precise
micro-ohm measurements possible without
calculating compensation for test-current­lead resistance errors.
A built-in discharge circuit automatically
discharges the energy stored in the
transformer at the end of each test.

1.5 Furnished Accessories

The Accu-Trans is shipped with two 45-foot
test cables with “quick disconnect” type test
plugs on the unit end and battery-type
clamps at the test load end. One power cord,
one ground cable, and a cable-carrying bag.

Accu-Trans Operating Procedures

4

2.0 ACCU-TRANS SPECIFICATIONS

Table 1. ACCU-TRANS SPECIFICATIONS

TYPE Special-purpose test equipment, portable, micro-ohmmeter
SIZE (inches) 16.8 wide by 12.6 high by 10.6 deep
WEIGHT Less than 21 pounds
RESISTANCE 1 micro-ohm to 200 ohms
TEST CURRENT 2 amperes max
DISPLAY LCD, back-lighted, 4-line by 20-character
PRINTER 2.5-inch wide thermal printer
ACCURACY ± 1 % reading, ± 1 count
POWER 2 amps, 90-120 / 200-240 V ac (selectable), 50/60 Hz
SERIAL INTERFACE RS-232C connector port
ENVIRONMENT Operating: 0°C to 55°C; Storage: -40°C to 65°C
WARRANTY One-year parts & labor (post warranty service is available)

NOTE:
THE ABOVE SPECIFICATIONS ARE VALID AT NOMINAL OPERATING VOLTAGE AND AT A TEMPERATURE OF 25 °C (77°F)

?ACCU-TRANS  SPECIFICATIONS MAY BE UPGRADED AND CHANGED WITHOUT PRIOR NOTICE.

Accu-Trans Operating Procedures

5

3.0 CONTROLS AND INDICATORS

(See Figure 1 and refer to Table 1.)
Accu-Trans controls and indicators are
shown in Figure 1.0. A leader line with an
index number points to each control and
indicator, which is cross-referenced to a
functional description in Table 2. This table
describes the function of each item on the

control-panel. The purpose of the controls
and indicators may seem obvious, but users
should become familiar with them before
using the Accu-Trans. Accidental misuse of
the controls will usually cause no serious
harm. Users should also be familiar with the
Safety Summary found on the front page of
this operator’s manual.

Figure 1.0 Accu-Trans Controls and Indicators

Accu-Trans Operating Procedures

6

Table 1.0 Functional Descriptions of Accu-Trans Controls and Indicators

Fig. 1

Index Panel Markings Functional Descriptions

1

RS-232C

2 (Not titled; 16-key pad) Pushbutton operating controls; 10 key pad, plus

3 (Not titled; LCD) Liquid-Crystal Display, 4-line by 20 character;

4 120/240 2A, 50-60 Hz

Fuse: 250 Vac, 3A Slow Blow

5 GROUND Stud, 5/16-18 thread, with hand-turned wing

6 (Not titled; thermal printer) Built in thermal printer; prints test results in the

7

HIGH CURRENT

PRESENT

8 (Not titled; test lead jacks) Test connector jacks, female; for connecting

Computer interface port; 9-pin connector;
female DB type.The data are set to 19,200
baud, 1 start bit, 2 stop bits, 8 data bits, and no
parity bit.

PIN SIGNAL
2 Rx
3 Tx
5 Signal Gnd

START, STOP, ENTER, CLEAR, two paper­drive buttons; number keys 2 thru 9 have dual
functions as letter entries (a la telephone dialer
key pad).

back lighted and readable in sunlight; Displays
menus, user selections, status readouts, and test
results.
Input power connector with third-wire safety
ground, ON (1)/OFF (0) rocker toggle switch;
has built-in fuse protection.

nut; Safety Ground; This must be connected to
station ground before connecting cables to
transformer and begin testing.

field on 2.5-inch-wide paper. NOTE: For best
high-contrast print quality, it is recommended
that only VIC thermal paper be used.
LED indicator light, red; When lighted, this
indicator warns operators that there is a
possibility that lethal high voltage will exist if
any test lead is disconnected while current is
running through an inductive load. Failure to

heed this warning can result in shock and/or
fatal injury to personnel.

heavy gauge current leads and voltage-sensing
test leads. Plug-in voltage plugs are not polarity
sensitive, but must be plugged into the jacks
adjacent to their companion current jacks.

Accu-Trans Operating Procedures

7

4.0 PRETEST SETUP

4.1 Operating Vo ltages

The Accu-Trans operating voltages are
selectable between 90-130Vac, 50/60Hz or
200-240, 50/60Hz. Voltage selection is set

Table 2.0 Voltage Selection

VOLTAGE SELECTION TERMINAL BLOCK JUMPERS

90-130Vac Brown to Blue & Yellow to Green

200-240Vac Blue to Yellow

by the placement of jumpers on the power

terminal block as listed in Table 2.0 below

and Figures 2.0 and 3.0.

120Vac Jumper Installation

Figure 2.0 90 to 130Vac Jumper Setting

Figure 3.0 210 to 240Vac Jumper Setting

220Vac Jumper Installation

Accu-Trans Operating Procedures

8

4.2 Accu-Trans LCD Contrast Control

To darken the LCD display, press and hold
the “Paper ∧ Contrast” switch for two

seconds; to lighten the LCD display, press
and hold the “Paper ∨ Contrast” switch for

two seconds.

4.3 Accu-Trans Printer Paper Control

To advance the Accu-Trans printer paper,
press and release the “Paper ∧ Contrast”

switch.
To retract the Accu-Trans printer paper,
press and release the “Paper ∨ Contrast”
switch.

5.0 ACCU-TRANS PRINTER PAPER

The Accu-Trans built-in thermal printer uses

2.5-inch wide thermal paper for printing test
results. To maintain the highest quality test­result printing and to avoid paper jamming,
the use of paper supplied by our factory is
highly recommended. Additional paper can
be ordered from either of the two sources
listed below:

Vanguard Instruments Co, Inc.

1710 Grevillea Court

Ontario, CA 91761
Tel: [phone]

Fax: [phone]

Part Number: TP-3 Paper

OR

BG Instrument Co.

13607 E. Trent Avenue

Spokane, WA 99216

Tel: [phone]

Fax: [phone]

Part Number: TP-3 paper

6.0 OPERATING PROCEDURES

Before using the Accu-Trans for measuring
any resistance, operators should review the

Summary of Step-by-Step Operation of the
Accu-Trans found in Figure 4.0. Accu-

Trans operations are simple, requiring the
selection of choices from the display menus
and responding to the displayed prompts.
However, first-time operators should review

Figure 1.0 to become familiar with the total

Accu-Trans operation and the logical

branching for various test options. (More

experienced operators may use this figure as

a handy help and reference guide.

WARNING

Do not touch or disconnect any test lead
that is connected to a transformer
terminal while high current is being
conducted during any test. Failure to

heed this warning can result in lethal
electrical shock to personnel and/or
damage to equipment.

6.1 General Procedures

a) Ground Accu-Trans to substation ground

(item 5 in Figure 1.0).

b) Plug Accu-Trans power cable into a

power outlet.

c) Insert current-cable plugs and voltage-

sensing cable plugs into respective control-

panel jacks (index 8 of Figure 1.0). Ensure

that voltage plugs are plugged into jacks that

are adjacent to companion current jacks.

d) Attach test-cable clamps to transformer

terminals of winding that is to be measured

(or if load is not an inductance, simply

attach test leads to opposite terminals of the

resistive load).

e) Turn on Accu-Trans power (item 4 in

Figure 1) by pressing “I” on rocker switch.

f) Observe that after configuration data is

displayed briefly, then the start-up menu

displays (with selection options for “1. RUN

TEST,” “2. SETUP”).

Accu-Trans Operating Procedures

9

Figure 4.0 Summary of Step-by-Step Accu-Trans Operation

Accu-Trans Operating Procedures

10

TEST IN PROGRESS

MEASURED RESISTANCE

1. TEST

XFMR

04/15/01

6.2 Step-by-Step Procedures at Start­Up Menu

6.2.1 START-UP Menu:

Observe that the Start-Up menu displays as
shown below:

2. SETUP 09:28:03

a) Press key #1 to start test. Press #2 to
select other options (i.e. enter record­identification data, recall test results, etc.)

6.2.2 Test Transformer Procedure

The following procedure shows the steps to
get a resistance reading from a device under
test.
a) To start a test, press key #1 (TEST
XFMR) from main menu. When the test
mode is selected, a “WARNING!” display is
shown below:

This display doesn’t prompt any action; but

simply reminds the user that a test is in

progress. The time for this display depends

on size of the winding’s inductance and the

test mode selected.

The Accu-Trans determines when the

resistance reading is stable and shows

resistance value on LCD as follows:

“STOP” TO ACCEPT

120.0 MICRO-OHM

The Accu-Trans continues to apply the test

voltage on the transformer’s winding and

updates the resistance value on the display.

d) The user presses STOP key to retain this

data and go to the next step. (If the displayed

data is not O.K., press CLEAR to return to

the Start-Up Menu.)

**********WARNING!**********
DANGEROUS FLASH-OVER
MAY OCCUR IF CABLES

ARE DISCONNECTED!

This warning reminds operators that the next
sequence of test steps will run current
through the load, which, if inductive, will
cause lethal voltages to be generated if the
cables are disconnected before the current is
ramped down to zero.

b) Press the ENTER key and proceed to the
next step. The start test display appears:

c) Press the START key to Start test. The
test-in progress display appears below:

PLEASE WAIT………

MEASURED RESISTANCE
FINAL RESISTANCE

120.0 MICRO-OHM

e) Press ENTER key and go to the next

step. The print-option menu is now

displayed.

PRINT TEST RESULTS

1. YES

2. NO

f) Press key #1 to print test results. Typical

Accu-Trans test report is shown in figure 5.

g) Select key #2 to bypass printing results.

* XFMR CHARGING*

Accu-Trans Operating Procedures

11

RUN ANOTHER TEST?

1. ENTER

XFMR DATA

1. COMPUTER CONTROL

h) When either option is selected, the next
window displays with the prompt “KEEP
THIS READING? Go to the next step.

KEEP THIS READING

1.YES

2. NO

i) If the KEEP THIS READING prompt is
answered with a YES, the following display
appears.
j) Go to step l. If NO is selected, the next
display is skipped and the second display
following appears.

TEST SAVED

m) At the “RUN ANOTHER TEST?”

Menu, the operator may choose to run

another test, by selecting “YES”. Return to

step 6.2.2.a to run test.

n) If NO is selected (i.e., don’t run another

test) the program returns to the Start-Up.

Menu (section 6.2.1).

6.3 SETUP Menu:

This menu is displayed by again selecting 2

(SETUP) on the Start-UP MENU

2. REVIEW RECORD

3. RESTORE RECORD

4. NEXT PAGE

The TEST SAVED display advises that the
resistance measurement has been saved.

k) Press ENTER and go to the next step.
“RUN ANOTHER TEST?” message will
appears.

l) Select NO from “KEEP THIS
RESULTS” will take the user to the “RUN
ANOTHER TEST?” menu.

1. YES

2. NO

a) Select key 1 to 4. When key #4 (NEXT

PAGE) is selected, More choices for setup

menu are shown (below).

2. SET TIME

3. ENABLE TEST MODE

4. VOLTAGE REG. TEST

Accu-Trans Operating Procedures

12

COMPANY:

Figure 5.0 Typical Test Report Printout

6.3.1 Transformer ID Entries:

The operator can enter test data using the
following procedures.

OPERATOR’S NOTE

Test Identification data are entered
with the keypad (item 2 of Figure 1.0).
The keypad has 10 keys that are alpha­numerically marked, like pushbuttons
on a telephone. Keys are pressed for
each character position (marked by the
cursor) in the identification area; thus:
If, for example, we consider the key
marked 2/A B C, the first press of the
key selects the number “2,” pressing
the key a second time selects the letter
“A,” pressing the key a third time
selects the letter “B, and pressing the
key a fourth time selects the letter “C.”
Further pressing of the key returns to
the number selection; the cycle repeats

as the key continues to be pressed. The
characters selected are entered at the
position of the cursor. Pressing the up
key (∧ ) advances the cursor by one

space; pressing the down key (∨ )
moves the cursor back one space. If a
character is erroneously entered, select
the new key to get the correct entry.

The first Identification (ID) display is the

COMPANY screen, which is shown below:

a) Enter the characters of the utility

company’s name. When this is done, press

Accu-Trans Operating Procedures

13

STATION:

CIRCUIT:

MANUFACTURER:

SERIAL NUMBER:

KVA RATING:

ENTER key and go to the next step. The
STATION screen will then be displayed.

b) Enter characters for naming the station
where the transformer to be tested is located.
When all the characters are selected or
identifying the station, press ENTER key
and go to the next step. The CIRCUIT
screen displays.

c) Enter all characters needed to identify
the circuit name, then press ENTER key and
go to the next step. The manufacturer screen
displays.

go to the next step. The SERIAL NUMBER

screen displays.

f) Enter the alpha-numeric characters

needed to identify the serial number, then

press ENTER key and go to the next step.

The KVA RATING screen displays.

g) Enter the numbers to identify the KVA

rating for the transformer being tested, then

press ENTER key and go to the next step.

The OPERTOR screen displays.

d) Enter all characters needed to identify
the manufacturer of the transformer being
tested, then press ENTER key and go to the
next step. The MODEL screen displays.

MODEL:

e) Enter the characters of the transformer’s
model number, then press ENTER key and

OPERATOR:

h) Enter the characters needed to identify

the operator who is performing the tests.

This completes entries for the transformer

identification data. Press ENTER key to

enter the selected data: the program returns

to the START-UP MENU.

6.3.2 Review Test Records Procedure

This procedure describes steps to review a

test record residing in Accu-Trans

working memory. The user can view the

record on the LCD display or from a thermal

printout.

Accu-Trans Operating Procedures

14

1. ENTER

XFMR ID

4. NEXT PAGE

REVIEW RECORD

2 TESTS

TEST NUMBER: 1

press the down (∨ ) key to roll down, through

NOTE

To review a test record stored in Flash
EEPROM, the user must first restore test
record from Flash EEPROM to working
memory (see paragraph 6.3.3).

These procedural steps begin by selecting
SETUP on the Start-Up Menu, which
displays the Set-Up Menu, shown below:

2. REVIEW RECORD

3. RESTORE RECORD

a) In the Set-Up Menu (see above), press 2
to select the REVIEW RECORD procedure.
It starts with the display shown below. Go to
the next step.

the saved test records.

The next menu displays the number of test.

in the record, time and date of the test.

There are 2 tests in the test record below.

06/12/ 01 12:21:34

f) Press the UP (∧ ) key to review the

resistance measured in the first test, which

show in the following display.

ACTIVE TEST

10.88 OHM
AT 0.824 Amps

1. SCROLL TEST RECORD

2. PRINT TEST RECORD

b) Press 1 (SCROLL TEST RECORD) to
view all the test records in memory (see
menu above).

c) Press 2 (PRINT TEST RECORDS) to
output test record to the thermal printer.
See Fig. 5.0 for typical test record printout.

d) Pressing the 1 key (SCROLL TEST
RECORD) produces the RECORD “ID”
INFO display. This menu displays the
information related to the test.

RECORD “ID” INFO:

g) Press the UP (∧ ) key again to display the

second test on the record as shown below:

TEST NUMBER: 2
ACTIVE TEST

122.8 MILLI-OHMs
AT 2.000 Amps

h) When the operator has reviewed the test

measurement for the selected record in the

display above, press STOP to return to the

Start-Up Menu. This ends the steps for

reviewing saved test records.

6.3.3 Restore Recording Procedures

This procedure allows the user to restore a

test record from the Accu-Trans Flash

EEPROM to working memory. The user can

then review the test record using the

REVIEW RECORD command (6.3.2).

e) To scroll through the test records in
memory, press the UP (∧ ) key to roll up or

The Restore Recording Procedure steps

begin at the Set-Up Menu, shown next:

Accu-Trans Operating Procedures

15

1. RESTORE RECORD

RESTORE RECORD

RESTORE RECORD

RECORD RESTORED!

1. ENTER

XFMR ID

REVIEW RECORD

1. ENTER XFMR ID

2. REVIEW RECORD

3. RESTORE RECORD

4. NEXT PAGE

a) To begin the Restore Recording steps,
press key # 3 (RESTORE RECORDING),
which shows a menu for three main
procedures, as displayed below. Go to next
step.

2. DIRECTORY

3. ERASE RECORDS

4. NEXT PAGE

b) Press key # 1 (RESTORE RECORD) to
begin the procedure. The next display
appears. Go to the next step.

1. ENTER RECORD NUMBER

2. SCROLL TO SELECT

c) Press # 1 (ENTER RECORD
NUMBER) to produce the Restore Record
display, as shown below. Go to next step.

The above display confirms to the operator

that the selected record has been restored.

e) When the restoration is confirmed, press

ENTER key to select the viewing option as

shown below.

1. SCROLL TEST RECORD

2. PRINT TEST RECORD

f) If the user wants to scroll through the

test record, press key #1 and continue from

step 6.3.2.b.

i) Press key # 2 will produce a test record

print out on the thermal printer. See figure

5.0 for a typical test record printout.

6.3.4 Printing Test-Record Directory

Printing the test record directory begins with

the Set-Up Menu shown below (the same

display from which the Review Records

steps began):

NUMBER:

The above display prompts the operator to
enter the record number.

d) When the record number is displayed,
press ENTER and go to the next step. The
next display will appear.

2. PREVIEW RECORD

3. RESTORE RECORD

4. NEXT PAGE

Accu-Trans Operating Procedures

16

1. RESTORE RECORD

PRINT DIRECTORY

a) Press key # 3 to select the Restore
Recording step sequence, and go to the next
step. The following menu displays:

2. DIRECTORY

3. ERASE RECORD

b) Press key # 2 (DIRECTORY) and go to
the next step. The menu below displays:

1. FULL DIRECTORY

2. SHORT DIRECTORY

c) Press key # 1 to print the entire directory

of test records; Press key # 2 to print the

short directory.

A short directory lists the last 20 test records

stored in the Accu-Trans memory.

This ends the print directory sequence.

Accu-Trans Operating Procedures

17

1. RESTORE RECORD

ERASE RECORD

Figure 6.0 Typical Record Directory Printout

6.3.5.Erase Recording Procedure

The Erase Recording sequence begins with
the Set-Up Menu, shown below. Go to the
next step.

1. ENTER XFMR ID

2. PREVIEW RECORD

3. RESTORE RECORD

4. NEXT PAGE

a) Press # 3 (RESTORE RECORD) and go
to the next step. The display below appears.

2. DIRECTORY

3. ERASE RECORD

b) Press # 3 (ERASE RECORD) and go to
next display.

ERASE RECORD

1. ERASE SINGLE REC.

2. ERASE ALL RECORDS

c) To erase a single a record, press key # 1;

to erase all records press key # 2. If a single

recording is selected go to the next step; The

prompt below displays. To erase all

recordings go to step f.

NUMBER:

Accu-Trans Operating Procedures

18

RECORD NUMBER

ERASE ALL RECORDS!

RECORD ERASED!

COMPUTER

ITF MODE

1. ENTER

XFMR ID

d) Enter the number of the record that is to
be erased and press ENTER key. Go to the
next step. The confirmation display appears
as shown below:

ERASED

e) When the erased record number is
confirmed, press ENTER key to return to the
start-Up Menu ending the sequence for
erasing a single record.

f) When key # 2 (ERASE ALL
RECORDS) is pressed in the Erase Record
display (back in step c, the following prompt
displays. Go to the next step.

6.3.6 Enabling Computer Interface

The Computer Interface Mode allows the

user to retrieve test records stored in the

Acccu-Trans memory via the RS-232C port

An IBM PC program is provided with each

Accu-Trans allowing the user using his PC

to retrieve these test records.

a) This procedure begins in the Set-Up

Menu, shown below. Go to the next step:

2. REVIEW RECORD

3. RESTORE RECORD

4. NEXT PAGE

b) Pressing key #4 (NEXT PAGE) and the

menu below appears. Go to the next step.

1. COMPUTER CONTROL

2. SET TIME

3. ENABLE TEST MODES

ARE YOU SURE?
“ENTER” TO CONTINUE

g) Press ENTER key to erase all test
records. If ERASE ALL RECORDS was
mistakenly selected, press “STOP” to abort
the erase process and return to the Start-Up
menu. When ENTER key is pressed, the
following confirmation message is
displayed. Press ENTER key to return to the
Start-Up Menue:

This ends the Erase Record(s) sequence.

c) Press key # 1 (COMPUTER

CONTROL) and go to the next step. The

display below appears:

j) Pressing the STOP key terminates the

computer control, at which time the Start-Up

Menu displays, ending this step sequence.

6.3.7 Setting Date and Time

The date and time set begins at the Set-Up

Menu, shown below:

1. ENTER XFMR ID

2. REVIEW RECORD

3. RESTORE RECORD

4. NEXT PAGE

Accu-Trans Operating Procedures

19

a) Begin the date and time set by pressing

key # 4 (NEXT PAGE) and going to the
next step. The menu below appears. Go to
the next step.

1. COMPUTER CONTROL

2. SET TIME

3. ENABLE TEST MODE

b) Press key # 2 (SET TIME) and go to the
next step. The display below appears:

ENTER

MM-DD-YY HH:MM:SS

c) Enter the date and time, which appear in
the dashed-line areas, then press ENTER
key to set the calendar and clock and return
to the Start-UP Menu. This ends the Set
Time step sequence.

6.3.8 Enable Passive Test Mode

Operators have a choice between two test
modes: ACTIVE or PASSIVE. Normally,
the ACTIVE test mode is best suited for
quickly testing transformer resistances. In
this mode, the Accu-Trans automatically
ramps the test current up to its final test
value (when the magnetic field is saturated)
in the shortest possible time. However, in a
very large inductive load, the ACTIVE test
mode reading may appear to be unstable.
In this situation, the user may want to try the
PASSIVE test mode test. In this mode, the
Accu-Trans will take longer to provide a
reading, however, the reading is more stable.

Note

The Accu-Trans always defaults to the
ACTIVE test mode when power is first
applied to the unit. The user needs to enable
the PASSIVE test mode before using it.

a) This procedure begins in the Set-Up

Menu, shown below. Go to the next step:

1. ENTER XFMR ID

2. REVIEW RECORD

3. RESTORE RECORD

4. NEXT PAGE

b) Pressing key #4 (NEXT PAGE) and the

menu below appears:

1. COMPUTER CONTROL

2. SET TIME

3. ENABLE TEST MODES

c) Press key #3 to activate PASSIVE Test

mode.

Note

Once the PASSIVE test mode is
selected, the Accu-Trans will display the
test mode selection menu (shown below)
in step 6.2.2.a after the user presses key
#1 (TEST XFMR).

1. ACTIVE TEST

2. PASSIVE TEST

6.3.9 Voltage Regulator Test

Note

This test verifies that a regulating
switch in a primary-voltage tap
regulator changes contacts through its
selection range with no break in the
circuit (i.e., it checks the tap switch’s
make-before-break). This test is
important because, in actual use, any
breaks in current in a regulating tap

Accu-Trans Operating Procedures

20

1. TEST

XFMR

08/14/01

1. ENTER

XFMR ID

1. COMPUTER CONTROL

ARE DISCONNECTED!

VOLTAGE REG. TEST

switch generates large reactive voltage
spikes that are hazardous and exceed
the switch’s voltage ratings, thus
causing irreparable damage.
By connecting the Accu-Trans
continuity test input across the
switching input and running the
regulator switch through all the
contacts in it’s range, any breaks in
continuity caused by faulty tap
switching are detected.

a) To run the Voltage-Regulator test,
perform the following step-by-step
sequence, starting with the STARTUP
MENU (see below):

2. SETUP 12:21:01

b) Press key #2 (SETUP) to produce the
SETUP MENU (see below):

e) Press ENTER key for next display (see

below):

f) Press START key to run the voltage

regulator tap-switch test. The test begins as

the magnetic field in the transformer ramps

up to a stable plateau with the advisory that

the transformer is charging (the red High-

voltage warning indicator lights) When the

transformer current stabilizes, the following

prompt displays (see below):

*****WARNING!*****

DANGEROUS FLASH-OVER

MAY OCCUR IF CABLES

VOLTAGE REG. TEST

“START” TO RUN TEST

or

“STOP” TO ABORT

2. REVIEW RECORD

3. RESTORE RECORD

4. NEXT PAGE

c) Press key #4 (NEXT PAGE) to produce
the next menu of test options (see next
display):

2. SET TIME

3. ENABLE TEST MODES

4. VOLTAGE REG. TEST

d) Connect Accu-Trans input to the
regulating tap-switch input. Press key #4
(VOLTAGE REG. TEST) to start the
regulator test (high-voltage advisory notice
displays—see following):

CURRENT RAMP: xx %

*XFMR CHARGING*

No operator action required; when

transformer current ramps nears a flat

plateau, the run tap switch prompt displays

(see below):

VOLTAGE REG. TEST

RUN TAP CHANGER NOW

“STOP” TO EXIT TEST

XFMR CHARGING

If no transient is detected as taps are

switching, the display above will remain.

Press “STOP” to end the voltage regulator

test.

Accu-Trans Operating Procedures

21

If a switch break is detected, an advisory
displays (shown below). Press STOP to end
the voltage-regulator test.

TRANSIENT DETECTED!

.

Accu-Trans Operating Procedures

APPENDIX A

ACCU-TRANS Troubleshooting Guide

Item Symptom Possible Problem Solution

1 Reading is incorrect. 1. Poor connection at the

Clips.

2. Broken sensing lead.

2 No Test Current.

(Current % read zero)
and resistance
reading=0

3 Have test current but

resistance reading =

0.

1. No test current going
through DUT.

2. Drive circuit not
working.

1. Broken sense leads.

2. Reverse sense leads.

1.Check connection to make sure
sensing and current teeth are
touching the device under test
(DUT).

2. Inspect sensing cables.

1. Check Connection to DUT.

2. Run Calibration Test.

1. Inspect sense leads.

NOTE: DUT=Device Under Test

1710 Grevillea Court, Ontario, CA 91761, USA

Phone: [phone] Fax: [phone]

Website: http//www.vanguard-instruments.com

ACCU-TRANS 09/09/01: OAK