Residual Voltage Tester

1. Unboxing and Basic Familiarization with the Device

1.1 Key Technical Specifications

Model	LS-RVT-2000W	LS-RVT-4000W	LS-RVT-5000W-3P
Maximum Output Power/Current	2000 W / 10 A, single-phase	4000 W / 16 A, single-phase	5000 W / 7.5 A, three-phase
Output Voltage Range	AC 0–242 V		AC 0–380 V
Test Residual Voltage Range	5–300.0 V; Resolution: 0.1 V; Accuracy: ±(1% of reading + 1 V)
Test Time	1–99 seconds
Test Impedance	≥100 MΩ (optional: >1000 MΩ)
Input Capacitance	25 pF
Test Alarm Range	5–300.0 V
Test Discrimination	Audible and visual alarms, and simultaneous disconnection of the output voltage
Communication Interfaces	RS-485 (optional)

1.2 Unboxing and Checking the Contents

1.2.1 Unpacking and Visual Inspection

When unpacking the device, handle it gently to avoid scratching the outer casing with sharp tools. After unpacking, first inspect the exterior of the device to ensure there is no visible deformation or dents, and that the buttons are not damaged or loose. If you notice any abnormalities with the device or its accessories, do not turn it on. Please contact us immediately.

1.2.2 Main Unit and Accessories

Number	Note
①	LS-RVT Series Residual Voltage Tester Main Unit
②	Power Cord
③	Alligator clip wire, used to connect the host device to the metal casing of the test specimen

Download links for the digital user manual, software, warranty card, and other materials have been sent via email. Please download them as soon as possible. If you missed the email, you can contact us to request the download links again.

1.3 Scope of Application of the Equipment

This device is designed in accordance with GB/T 4706.1-2024 (Clause 22.5), GB 8898-2011 (Clause 9.1.6), GB 9706.1-2020 (Clause 8.4.3), GB/T 7000.1-2023 (Clause 8.2.7), and GB 4943.1-2022 (Clause 5.5.2.2). It is suitable for residual voltage testing of medical devices, household appliances, portable lighting fixtures, power connectors, and related equipment.

It can detect residual voltage between plug pins (live-neutral, live-ground, neutral-ground) and between the pins and the device housing, verifying whether the safety of capacitor discharge after the device is powered off meets standard requirements.

1.4 Key Design Considerations

By simulating the act of unplugging the device, it is disconnected from the power grid voltage at its peak (90/270 degrees). The test shows an impedance of ≥100 MΩ and an input capacitance of 25 pF, which meets the standard’s requirements for the input characteristics of measuring instruments, ensuring accurate and interference-free measurement results.

2. Safety Precautions

2.1 Electrical Safety

Different equipment models have different input voltages, either AC 220V or AC 380V. Ensure that the input power supply matches the requirements on the equipment nameplate. Never connect the equipment to a voltage other than the rated voltage to prevent short circuits or equipment damage.

The equipment must be properly grounded. Before testing, check that the grounding terminal is securely connected. Do not start the test if the equipment is not grounded to prevent the risk of electric shock.

During operation, avoid contact with live parts such as the test specimen sockets and terminals. Wear insulated gloves during testing and keep your hands dry.

2.2 Operating Procedures

When adjusting the voltage control knob, turn it slowly clockwise; do not make rapid or drastic adjustments to avoid damaging the internal electronic components. After completing the test, be sure to first turn the voltage control knob counterclockwise to the minimum setting before turning off the power.

It is recommended to set the power-on duration to 1–3 seconds to prevent the equipment from overheating or the test specimen from being damaged due to prolonged power supply. The default number of test cycles is 10; this can be adjusted according to the standard, but should not exceed the maximum limit of 99.

When testing high-current (＞10A) specimens, use the high-current terminals on the side of the equipment; do not connect through the 10A specimen socket to prevent the connector from overloading and burning out.

2.3 Environment and Protection

The equipment should be used in a dry, well-ventilated environment free of corrosive gases, with an ambient temperature of 0–40°C and relative humidity of ≤85%. Avoid moisture or excessive dust, which can cause equipment malfunctions.

Do not cover the ventilation openings while the equipment is running, and do not place flammable or explosive materials near the equipment. If an alarm sounds, stop the test immediately and restart the equipment only after troubleshooting the problem.

2.4 Other

For matters not covered in this manual, please proceed with caution or contact us.

3. Equipment Overview

3.1 Front of the Device

Number	Note
① Pressure adjustment knob	Clockwise to increase voltage, counterclockwise to decrease voltage; the adjustment range is 0–242 V AC for single-phase and 0–380 V AC for three-phase. The test voltage is used to power the test specimen.
② Touchscreen	Displays test parameters and data results, and allows users to configure settings, etc.
③ Power Switch	Controls the power on and off of the device; the touchscreen turns on automatically after startup.
④ Start Button	Once the parameters have been set, press this button to start the test process, and the device will run according to the preset program.
⑤ Stop Button	If an emergency stop occurs during testing or operation is terminated after testing is complete, pressing this button will cut off the device’s output voltage.
⑥ Warning light	When the residual voltage exceeds the set alarm threshold, a red light illuminates, accompanied by an audible and visual alarm, and the power output is simultaneously cut off.
⑦ Specimen Socket	Suitable for test specimens rated at ≤10A; connect the test specimen’s power plug; during testing, the unit outputs the set voltage and measures the residual voltage.

Figure 1

3.2 Side View of the Device

Chassis Connection Terminal: Connect a wire with an alligator clip to the metal chassis of the test specimen to measure the residual voltage between the pins and the chassis. If not required, keep the terminal clean and free of short circuits.

Figure 2

The LS-RVT-4000W high-power device also includes high-current terminals, which are suitable for high-power test specimens rated at >10 A and serve as a replacement for test specimen sockets.

Figure 3

The LS-RVT-5000W-3P three-phase device is also equipped with terminal blocks as standard. This three-phase device can test both single-phase and three-phase specimens. When testing a single-phase specimen, simply connect one phase wire, the neutral wire, and the ground wire to the terminal blocks. Be sure to select the corresponding phase wire when setting the parameters.

3.3 Back of the Device

Product nameplate and power cord.

Note: The LS-RVT-2000W standard unit comes with a standard plug-and-play power cord, while the LS-RVT-4000W high-power unit and the LS-RVT-5000W-3P three-phase unit come with fixed power cords featuring pre-wired terminals; please connect the power cord terminals to an appropriate power source.

4. Introduction to the Touchscreen Program

4.1 Monitoring Interface

Number	Note
① Voltage Display	Indicates the Voltage Regulator’s output voltage (in V); when starting the test, power the test specimen at this voltage.
② Current Display	Displays the real-time current (in A) flowing through the specimen during testing
③ Power Display	Displays the real-time power consumption of the test specimen (in watts)
④ Residual Voltage	Displays the remaining voltage measurement for the current test (in V)
⑤ Timer Display	Alternately displays the power-on countdown and the power-off countdown (in seconds)
⑥ List of Residual Voltage Test Values	Displays the remaining voltage data (in V) for cycles 1–10 of the test
⑦ Arithmetic value of the residual voltage	Displays the maximum, minimum, and arithmetic mean of the test values (in volts), allowing for a quick determination of compliance.
⑧ Settings Button	Click to open the settings screen

Figure 4

4.2 Parameter Settings Interface

Number	Note
① The appliance is powered on	Set the power supply duration for the test specimen. The default is 3 seconds, but this can be adjusted according to the standard (for example, if GB 4706.1 requires a 1-second power interruption, set it to 1 second).
② Cyclic Measurement	Set the number of consecutive tests; the default is 10. GB 8898 requires 10 repetitions to identify the worst-case scenario; it is recommended to keep the default setting.
③ Time-Delay Measurement	Set the delay time before measurement begins after a power outage. The default is 1 second; this must be set according to the applicable standard (e.g., set to 2 seconds if GB 8898 requires 2 seconds, or to 5 seconds if GB/T 7000.1 requires 5 seconds).
④ Power-off angle	The default setting is 90/270 degrees (voltage peak), which meets the “peak-off” requirement of the standard and requires no modification.
⑤ Alarm Voltage	Set the upper limit for residual voltage according to standard specifications (e.g., ≤34 V for household appliances, ≤60 V for medical devices, ≤50 V for lighting fixtures, etc.)
⑥ Selection of Measurement Items	Options include Live-Neutral (LN), Live-Earth (LE), Neutral-Earth (NE), Live-to-Shell (L Shell), and Neutral-to-Shell (N Shell). Select the appropriate option based on your testing needs. To measure voltage to ground, you must connect both the ground terminal and the test lead. To measure voltage to the shell, you must connect both the alligator clip and the test lead.
⑦ Calibration Button	No action is required. If the device displays abnormal parameters, please contact us for calibration.
⑧ Back Button	Save the settings and return to the monitoring screen

Figure 5

5. Preparations Before the Test

5.1 Sample Preparation

Check that the specimen is free of damage and that the power plug is intact; then insert the specimen’s power plug into the equipment’s specimen socket (≤10A) or connect it to the high-current terminal block (>10A);

To test the residual voltage between the test pin and the enclosure, connect one end of the alligator clip lead to the device’s ground terminal and clip the other end to the metal enclosure of the test specimen (ensuring good contact and no oxidation);

Set the test specimen’s switch to the “On” position. If the test specimen has multiple switches, set them to the most unfavorable positions (as required by the standard, the switches may affect the discharge results).

5.2 Parameter Presets

Configure the settings as described in Section 4.2.

6. Residual Voltage Test

6.1 Initiating the Test Process

On the monitoring screen, slowly turn the voltage adjustment knob clockwise to set the output voltage to the test specimen’s rated operating voltage (e.g., 220 V). Stop adjusting once the voltage reading has stabilized;

Press the “Start” button on the front of the device, and the device begins to operate according to the preset program: it supplies power to the test specimen for the “Appliance Power-On” duration; at this point, the current and power displays show normal values; Once the power supply time has elapsed, the device cuts off the power supply at the peak voltage and enters the power-off countdown; after the “Delayed Measurement” time has elapsed, it automatically measures the residual voltage of the selected parameter, and the results are saved to the test value list; After completing a single test, following a 10-second power-off interval, the device automatically repeats the above steps until the “Cycle Measurement” count is reached.

6.2 Monitoring the Testing Process

During the test, monitor the status of the alarm indicator. If the remaining voltage exceeds the alarm threshold, the device will immediately trigger an audible and visual alarm and cut off the output. Press the stop button to clear the alarm, record the data that exceeded the threshold, and inspect the test specimen;

During the cycle test, the device automatically records data without requiring manual intervention.

6.3 Evaluation and Recording of Results

Once the test is complete, the device automatically stops outputting power. Check the “Remaining Voltage Arithmetic Values” (maximum, minimum, and average) on the monitoring interface;

Pass/Fail Criteria: If none of the test values exceed the set alarm voltage (and comply with the corresponding standard limits), the test specimen passes; if any value exceeds the limit, the test specimen fails;

Record all test data (values from 10 cycles, maximum, minimum, and average) and include information such as the test standard, specimen model, and test date; file the records for future reference.

6.4 Equipment Shutdown Procedure

After testing is complete, first slowly turn the voltage adjustment knob counterclockwise to set the output voltage to the minimum (0 V); press the stop button, and after confirming that the device has cut off the output, turn off the device’s power switch; remove the test specimen and its connecting cables; if alligator clip leads were used, put them away promptly.

7. Daily Maintenance and Care of Equipment

7.1 Routine Maintenance

Before turning on the equipment, check that the exterior is clean and free of damage, that the power cord and alligator clip wires show no signs of aging or breakage, and that all connectors are secure;

After the test is complete, wipe down the surface of the equipment and the test area of the specimen with a dry cloth;

Check the test specimen sockets and high-current terminals for oxidation or burnout; if any are found, wipe them with a specialized contact cleaner. If necessary, contact us to have the terminals replaced;

Check to see if the cooling fan inside the equipment is operating normally. If you hear any unusual noises or if it is not running, contact us immediately for repair.

7.2 Long-Term Storage

If the device will not be used for an extended period, store it in a dry, well-ventilated environment, away from moisture and direct sunlight;

Disconnect all cables, store the accessories separately, and cover the device with a dust-proof cloth;

Turn on the device for 30 minutes each month to prevent the internal electronic components from deteriorating.

Troubleshooting and Resolving Common Issues

Fault Symptoms	Possible Causes	Procedure
No voltage output after starting the test	The voltage adjustment knob is not set to the rated voltage; the test specimen is not connected to the power supply.	Turn the voltage adjustment knob clockwise to the specified voltage; check that the test specimen switch is turned on and that the plug is securely connected.
The measured value is 0 or abnormally low	Incorrect selection of measurement items, poor grounding, or test specimens not functioning properly	Return to the parameter settings screen to verify the measurement items; check that the alligator clip leads are securely connected to the specimen housing; confirm that the specimen operates normally after power is applied.
Frequent alarms, readings exceed limits	Incorrect alarm voltage setting, malfunction of the specimen discharge device	Verify the standard limit values and reset the alarm voltage; check whether the internal discharge resistor in the test specimen is damaged, and retest after replacing the specimen.
The touchscreen is unresponsive	Equipment Freezes, Touchscreen Malfunctions	Turn off the power, wait 30 seconds, and then turn it back on; if there is still no response, contact us to have the touchscreen repaired.
Abnormal Current/Power Display	Short circuit in the test specimen; poor contact at the terminals	Stop the test immediately and check whether the test specimen has a short circuit; reconnect the test specimen’s plug or terminals to ensure good contact.