HVTest HTZZ-1A User manual

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Dear Client
Thank you for Purchasing our HTZZ-1A Transformer DC
Winding Resistance Tester. Please read the manual in detail
prior to first use, which will help you use the equipment skillfully.
Our aim is to improve and perfect the company's
products continually, so there may be slight
differences between your purchase equipment and
its instruction manual. You can find the changes in
the appendix. Sorry for the inconvenience. If you
have further questions, welcome to contact with our service
department.
The input/output terminals and the test column
may bring voltage, when you plug/draw the test wire
or power outlet, they will cause electric spark.
PLEASE CAUTION RISK OF ELECTRICAL SHOCK!
Company Address:
T4，No. 41, High-tech 2 Road，East Lake High-tech Development
Zone，Wuhan
Sales Hotline: [phone]
After Service Hotline:[phone]
Fax: [phone]
E-mail: [email protected]
Website: www.hvtest.cc

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SERIOUS COMMITMENT
All products of our company carry one year limited warranty
from the date of shipment. If any such product proves defective
during this warranty period we will maintain it for free. Meanwhile
we implement lifetime service. Except otherwise agreed by
contract.
SAFETY REQUIREMENTS
Please read the following safety precautions carefully to avoid
body injury and prevent the product or other relevant subassembly
to damage. In order to avoid possible danger, this product can only
be used within the prescribed scope.
Only qualified technician can carry out maintenance or repair
work.
--To avoid fire and personal injury:
Use Proper Power Cord
Only use the power wire supplied by the product or meet the
specification of this produce.
Connect and Disconnect Correctly
When the test wire is connected to the live terminal, please do
not connect or disconnect the test wire.
Grounding
The product is grounded through the power wire; besides, the
ground pole of the shell must be grounded. To prevent electric
shock, the grounding conductor must be connected to the ground.

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Make sure the product has been grounded correctly before
connecting with the input/output port.
Pay Attention to the Ratings of All Terminals
To prevent the fire hazard or electric shock, please be care of
all ratings and labels/marks of this product. Before connecting,
please read the instruction manual to acquire information about the
ratings.
Do Not Operate without Covers
Do not operate this product when covers or panels removed.
Use Proper Fuse
Only use the fuse with type and rating specified for the
product.
Avoid Touching Bare Circuit and Charged Metal
Do not touch the bare connection points and parts of
energized equipment.
Do Not Operate with Suspicious Failures
If you encounter operating failure, do not continue. Please
contact with our maintenance staff.
Do Not Operate in Wet/Damp Conditions.
Do Not Operate in Explosive Atmospheres.
Ensure Product Surfaces Clean and Dry.

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－Security Terms
Warning: indicates that death or severe personal injury may
result if proper precautions are not taken
Caution: indicates that property damage may result if proper
precautions are not taken.

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Contents
Overview....................................................................6
Application................................................................7
Performance characteristics................................ 7
Specifications........................................................... 7
Panel Layout............................................................. 9
Working Principle................................................... 9
Operation Methods............................................. 10
Problems and Solutions..................................... 12
Notes........................................................................ 12
Packing List.............................................................13

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Overview
DC resistance measurement of transformer winding is an essential
test project during transformer transfer, repair and changing tapping
switch.Measuring DC resistance of transformer winding, you can check
out weld or connection quality of down-lead, the winding inter-turn
short circuit or open circuit, and whether tap-changer is well contacted.
In the previous it is generally to use QJ44 double bridge to measure DC
resistance, but the measuring current for this type of bridge is mA level
current. So measurement will take a long time, and accuracy is lower. In
order to change the above situation, our company has developed
HTZZ-1A DC Resistance Rapid Tester.
This instrument is a high-precision regeneration product used to
replace DC single/double bridge. Equipped with advanced switch power
supply technology,the measurement speed of the instrument is faster a
hundred times than that of the bridge. Using four and half bits LCD to
display the measurement results and three and half bits LCD to display
ambient temperature or test current value, it overcomes the
shortcoming of other similar products that it is difficult to read value
from the LED display in the sun and possesses automatic arc
suppression function. The instrument is characterized by fast test speed,
high precision, intuitive display, strong anti interference ability, small
size, low power consumption, stable and reliable test data. Built-in
rechargeable battery pack (12V) and AC/DC dual-use, the instrument is
very convenient for on-site and field test.
The instrument meets DLT 845.3-2004 "resistance measurement
device general technical requirements- Part 3 DC Resistance Tester"
requirements.

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Application
The instrument is an ideal device to measure different inductive
load DC resistance and of low-voltage switch contact resistance, wire
and cable resistance, welded joint resistance of power transformers,
large motors and instrument transformers.
Performance characteristics
1. Fast test: The maximum output charge current of the instrument
is up to 1A. When measuring it can effectively compensate current
inertial for large inductor and accelerate core saturation, thereby
reduced the charging time and increased test speed. Its test speed is
faster hundreds of times than the traditional single instrument and
double bridge.
2. High accuracy: The application of advanced four-terminal
measurement and constant current source technology to the
instrument makes the inductive load charging current hold a relatively
stable value. Base on that, and the instrument with stable anti-sense
capability and strong anti-interference characteristics can ensure the
accuracy of measurement. And the use of imported high-quality
components not only improves the measurement accuracy, but also
makes the instrument have good repeatability.
3. Wide measurement range: resistance measurement range 1μΩ ~
2KΩ, wide range.
4. AC and DC power supply: Attached rechargeable battery, the
instrument can use AC and DC power supply. Portable design, it is easy
to carry and use.
Specifications
1. Work Environment:
Temperature: 0℃～40℃

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Relative Humidity: ≤85 %
2. Measurement Range:
The instrument has six ranges as follows:
1μΩ～20mΩ;
20 mΩ～200mΩ;
0.2Ω～2Ω;
2Ω～20Ω;
20Ω～200Ω;
200Ω～2kΩ
2kΩ～20kΩ
3. Measurement Accuracy：±(0.2%+2d)
4. Maximum Resolution: 1μΩ
5. Constant current source:
1A (1μΩ～20mΩ, 20 mΩ～200mΩ, 0.2Ω～2Ω);
100mA (2Ω～20Ω); 5mA（20Ω～200Ω）；
500uA（200Ω～2kΩ）；;
50uA（2kΩ～20kΩ）。
6. Working Voltage:
DC: 12V～16.8V
AC: 220V
7. Power Dissipation: ≤15W
8. Dimension: 365×330×180mm
9. Weight：5kg (included test clamp and test lead)

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Panel Layout
Figure 1 Panel Layout diagram
1 Resistance Display (A) 7 Test connection port
2 Temperature/Current display 8 earth
3 Resistance range selector key 9 220V Power Outlet
4 Temperature/Current selected key 10 Power Switch
5 Start/Stop key 11 Power Indicator
6 Working Station Indicator
Working Principle
There is a constant current source in the instrument that can supply
DC current. When measuring resistance, constant current be fed into
the tested object from terminals I +, I-, then which will yield voltage in
the tested object, the value of that voltage retake to the instrument at
terminals V +, V, after amplification, the display will show the resistance
value using four and a half bits LCD digital.

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Operation Methods
1. Power supply
This instrument provides two power sources for test:
AC220V/DC12V. In the case of strong electromagnetic interference, the
best choice is use the DC power supply for test. At this state the
instrument can get stable tested value with strong anti-frequency
interference ability.
1) DC power supply test:
Closed power switch, power indicator will light. Press “start/stop”
buttons, then select appropriate resistance gear switch to do the test.
Finished testing, press “start/stop” button, "discharge" indicator lights
(if the stored electricity of tested object is little, the "discharge"
indicator does not light), after discharge, "discharge" indicator goes out,
and then convert the test clip for re-test.
2) AC power supply test:
Connect to AC 220V power supply, its indicator lights ("charging"
indicator or "full" indicator); closed the power switch, power indicator
lights, and press the "start/stop" button, then select appropriate
resistance gear switch to do the test. Finished testing, press “start/stop”
button, "discharge" indicator lights (if the stored electricity of tested
object is little, the "discharge" indicator does not light), after discharge,
"discharge" indicator goes out, and then convert the test clip for re-test.
3) Charge
Connect to AC220V power supply, "charging" indicator lights
indicating the rechargeable battery is charging. If rechargeable battery’s
power is sufficient, "full" indicator will light. When using AC power to
test, the instrument also can charge up the battery. (Instrument
equipped with charging protection circuit will not produce
overcharging phenomenon.)

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2. Test line connection method
Well connect terminal I +, V +, V-, I- to the tested target as the
wiring method in Figure 1. The connection method can eliminate the
effect of contact resistance and line resistance on the measurements.
Tested
target RX
Instrument Host
In measuring, if the length of test line is not enough, you can use
lead having same size diameter to extend it.
3. Measurement
Well connected the test line as fig. 2, closed power switch, power
indicator lights, and press the "start/stop" button, then the display
shows "E0000". According to the measured value select appropriate
resistance gear range, press its switch, then its indicator lights, the four
and half bits digital stably shown in LCD is the measured resistance
value. When reading resistance value, please pay attention to the unit
of selected range (mΩ / Ω / kΩ). Measuring large inductance such as
power transformer, you’d better keep the coils not measured short-
circuited to avoid electromagnetic interference.
4. Discharge
Finished measurement, you can directly disconnect main power. For
measuring inductive object, it is not recommended immediately
disconnect the wiring after disconnected the power, the instrument
should be left to continue discharge. General discharge time is at least

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20 seconds; otherwise the EMF of the inductance could endanger
personal safety.
Problems and Solutions
Notes
1. After testing, please charge up the battery in time.
2. During DC test, if the undervoltage indicator light became bright,
pleaseuse AC power instead of DC power for test.
3. If the instrument will not be used in long-term, please charge up
thebattery regularly (two month) until the "full" indicator lights up,
generally chargetime is about 14 hours.
4. Yo u should prevent the instrument damp, falling, and exposure.

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Packing List
1. Instrument host 1
2. Test lead 1
3. Earth wire 1
4. Fuse（2A） 3
5. AC 220V Power cord 1
6. The instruction manual 1
7. Certificate 1