Wuhan Huatian Electric Power Automation HTDT-10A User manual

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Dear Client
Thank you for Purchasing our HTDT-10A Ground Continuity
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

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ground pole of the shell must be grounded. To prevent electric
shock, the grounding conductor must be connected to the ground.
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
I. Overview................................................................................. 6
II. Functions...............................................................................7
III. Features................................................................................ 7
IV. Specifications..................................................................... 8
V. Panel Layout.........................................................................9
VI. Work Principle.................................................................... 9
VII. Operation Methods........................................................ 10
VIII. Problems and Solutions..............................................12
IX. Notes................................................................................... 13
X. Packing List........................................................................13

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I. Overview
The electrical integrity of earthing device is the electrical
connectivity among all kinds of electrical devices that should be
grounded or the electrical connectivity between ground equipment
all parts and devices, it is DC resistance value; it is also known as
electrical conductivity. Ground down lead and earth mat of electrical
equipment reliable and effective connection is the fundamental
guarantee of instrument safety operation. Ground down lead is the
connection part of electrical equipment and earth mat. In the
long-term running, the connection part may be rusty even ruptured
due to moisture and other factors, which will cause the resistance
increases which at connection point of ground down lead and the
main earth mat, and thus cannot meet the requirements of
electrical power regulations and standard. It also cause the
instrument hides danger in work, seriously even cause the
instrument run in lost ground status. Underground ground electrode
and its connection parts may rusty, and even ruptured. Therefore, it
is necessary to regularly do the electrical integrity test of grounding
devices.
Electric Power Industry Standard PRC-DL/T475-2006
“Earthing Device Characteristic Parameters Measurement Guide”

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provides that the electrical conductivity should use special
instruments to measure. The instrument resolution is 1mΩ;
accuracy is not less than 1.0 class. Based on this standard, our
company designed this high degree of automation and portable
tester. It is specially used to test the electrical integrity of earthing
device; its technical specification has reached or exceeded the
relevant standards. The instrument is characterized by simple
operation, high accuracy, fast test speed, good reproducibility, and
intuitive readings. It is an ideal special instrument that meets the
requirements of regulations and standard.
II. Functions
The instrument is suitable for measuring on-resistance value
between electrical equipment grounding down-lead and earth mat
(or adjacent devices). It also applies to measure low-value resistor.
III. Features
(1) Power technology: For latest power supply technology, the
instrument outputs 10A current and can continuously work for a
long time which overcomes the weakness of instantaneous current
produced by pulsed power. It can effectively puncture the oxide
layer of the switches and then get precise results.

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(2) Strong anti-interference ability: The last number of test data
will stably show in the LCD screen only with ±1 error even in strong
Interference situation.
(3) Long service life: All the precise resistances used in the
instrument can reduce the temperature’s impact on the
measurement results and military connectors can enhance
vibration resistance.
(4) Simple operation: just pressing “test” key, you can get the
measured result. The LED display is easy for reading and has
good reproducibility.
(5) Convenience: Small size, light weight, and easy to carry.
Panels and chassis is an organic whole that having good shock
resistance.
IV. Specifications
(1) Measurement Range: 1～1999mΩ
(2) Resolution: 1mΩ
(3) Test Current: DC 1A, 2A, 5A, 10A.Four fixed current input
selections.
(4) Measurement Accuracy: ±(0.5%+2d)
(5) Measuring Radius: 50 m
(6) Display: LED display

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(7) Work Mode: Continuous
(8) Power Supply: AC220V±10% 50Hz
(9) Work Environment:
Temperature: -10℃～40℃Humidity: ≤80 %RH
(10) Dimension: 300×270×200 mm3
(11) Weight: 5kg（Accessories excluded）
V. Panel Layout
Figure 1 Panel Layout diagram
1、 Resistance Display
（mΩ）
2、Grounding
3、Current Output I+
4、 Measurement Input U＋
5、 Measurement Input U-
6、Current Output I－
7、220V Power Outlet
8、Power Switch
9、Stop/Measure
10、Current Selection
VI. Work Principle
The instrument bases on the current-voltage testing principle

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that also known as Four-line method testing technology. More
details show in Figure 2.
Figure 2 Schematic diagram
The current goes through I+ and I- ports to the resistance Rx,
current value can be got from the ammeter I, and the voltage
between V+ and V- will be shown in the voltmeter V. Based on data
I and V, the resistance value can be calculated.
From the above diagram we can know that using four-terminal
measurement can eliminate the error caused by lead resistance
and contact resistance.
VII. Operation Methods
1、Wire as shown in the Figure 3.

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Figure 3 Four-terminal Wiring diagram
The instrument has two test lines: a 50-meter red line on the
plate, please connect the large fork to the red terminal I +, and
connect the small fork to the red terminal U +; let the large fork of
5-meter black line connect to black terminal I-, and the small one to
the black terminal U-.
2、First find out the down lead well connected with ground mat
as a reference point.
3、The two test lines (50 m, 5 m) , connect two ends of them to
wire holder; Connect other two ends with test clips to the reference
point and measured point (among which, the black test line clips
the reference point, the red test line clips all tested points).
4、In order to get accurate measured data, please keep contact
surface of the measured point clean.
5、After confirmed the wiring is well connected, access to 220V

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AC power supply, turn on power switch, the instrument enter into
the starting up state. Press "test" key to begin test, the middle of the
display screen shown measured resistance is the on-resistance
values, its unit is mΩ.
Please refer to the following table to check the test result is
normal or not.
on-resistance
150mΩ
500mΩ
1Ω
Status
Good
Abnormal
Severely abnormal
6、Completed measurement, please disconnect the power
switch and put the test lines into accessories bag.
VIII. Problems and Solutions
Problems
Solutions
No respond after powering
on; on the LCD no display
Check if AC power is on
Check the power cables
Check if the Fuse is Blown out.
Under test resistance value is
evidently larger or 1 ( beyond
range)
Check if measured resistance value is
too large
Check if voltage input lines places on the
inner side of current output lines.
Check if voltage output lines have poor
contact or the port connected to the test
object is oxidized.

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IX. Notes
(1) Please read the manual carefully before using this tester
and wire properly as recommended in this manual.
(2) During testing, please make sure power supply of
measured device turn off and it disconnects from other energized
equipment.
(3) The instrument should be firmly grounded during testing.
(4) Replacing the fuse and accessories, please use the same
model with the instrument.
(5) The instrument should be put in ventilated, dry, cool and
cleaning place. Pay attention to humid or erosive gas that may
damage this equipment.
X. Packing List
1. Instrument host
1
2. Test line (50m red line and 4m black line)
3. AC three-wire power cord
1
1
4. Earth lead
1
5. Test line accessory bag
6. Fuse（2A）
1
2
7. The instruction manual
8. Certificate
1
1
9.Inspection report
1

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