1. Product Overview
The OUKANING STU-3000 is a versatile 3000W Step Up & Down Voltage Converter designed to safely and reliably convert electrical voltages. It allows for conversion from 110V to 220V, or from 220V to 110V, making it suitable for a wide range of home and industrial applications. This unit features multiple output options, including 110V AC, 220V AC, and a 5V DC USB port, all of which can be used simultaneously.

Figure 1: Front view of the STU-3000 converter, showing the 110V and 220V output sockets, USB port, and power switch.
Key Features:
- Selectable Input Voltage: 110V/220V AC.
- Multiple Output Options: 110V AC, 220V AC, and 5V DC USB.
- High Power Capacity: Maximum rated power of 3000 watts.
- Simultaneous Use: All five output ports (four AC, one USB) can be used concurrently.
2. Important Safety Information
Please read and understand all safety instructions before operating this voltage converter. Failure to follow these instructions may result in electric shock, fire, or serious injury.
WARNING:
- Input Voltage Selection: ALWAYS select the correct input voltage (110V or 220V) using the selector switch on the rear panel BEFORE connecting the unit to a power source. Incorrect selection can cause severe damage to the converter and connected appliances.
- Power Matching: For safety, the maximum power of the voltage converter should be at least 1.5 times greater than the rated power of the appliance you intend to connect. For example, if your appliance is 100 watts, use a converter with a maximum power of 150 watts or more.
- Ventilation: Ensure adequate ventilation around the converter. Do not block the ventilation grilles.
- Indoor Use Only: This device is designed for indoor use in dry environments. Do not expose to rain, moisture, or extreme temperatures.
- Grounding: Ensure the converter is properly grounded.
- Children: Keep out of reach of children.

Figure 2: Rear view of the STU-3000, highlighting the input voltage selector and safety warning.
3. What's in the Box
Upon unpacking, please ensure all items are present and in good condition:
- OUKANING STU-3000 3000W Voltage Converter
- Power Cord (approximately 3 feet long)
4. Setup Instructions
Follow these steps to set up your voltage converter:
- Unpack the Converter: Carefully remove the converter from its packaging.
- Placement: Place the converter on a stable, flat surface in a well-ventilated area. Ensure there is sufficient space around the unit for airflow, especially near the ventilation grilles on the sides.
- Select Input Voltage: Locate the input voltage selector switch on the rear panel of the converter. BEFORE connecting the power cord, use a flat-head screwdriver or a similar tool to slide the selector to match your local power supply voltage (e.g., 110V or 220V).

Figure 3: Detail of the input voltage selector switch. Ensure this is set correctly before use.
- Connect Power Cord: Insert the included power cord into the AC input socket on the rear of the converter.
- Connect to Wall Outlet: Plug the other end of the power cord into a grounded wall outlet that matches the selected input voltage.
- Power On: Flip the ON/OFF switch on the front panel to the 'ON' position. The power indicator light should illuminate.
5. Operating Instructions
Once the converter is set up and powered on, you can connect your appliances:
- Identify Output Voltage: The front panel has clearly labeled output sockets for 110V and 220V. There is also a 5V USB output.
- Connect Appliance: Plug your appliance into the appropriate output socket on the front panel. Ensure the appliance's voltage requirement matches the socket's output voltage.
- USB Charging: For charging USB devices, connect them to the 5V USB port.
- Simultaneous Use: You can use multiple output sockets and the USB port simultaneously, provided the total power consumption does not exceed the converter's 3000W maximum rated power. Remember the 1.5x safety margin for connected devices.
- Power Off: When finished, turn off the converter using the ON/OFF switch before disconnecting any appliances or the main power cord.

Figure 4: Detailed view of the front panel with output sockets and controls.
6. Maintenance
Proper maintenance ensures the longevity and safe operation of your voltage converter:
- Cleaning: Disconnect the converter from the power source before cleaning. Use a soft, dry cloth to wipe the exterior. Do not use liquid cleaners or solvents.
- Ventilation: Periodically check that the ventilation grilles are free from dust and obstructions. Use compressed air if necessary to clear dust.
- Storage: Store the converter in a cool, dry place when not in use.
- Fuse Replacement: The unit is equipped with a fuse for protection. If the converter stops working, check the fuse located on the rear panel. Replace it with a fuse of the same type and rating if blown.

Figure 5: Rear view showing the fuse holder (labeled 'FUSE') and input voltage selector.
7. Troubleshooting
If you encounter issues with your OUKANING STU-3000, refer to the following common problems and solutions:
| Problem | Possible Cause | Solution |
|---|---|---|
| Converter does not power on. |
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| Appliance connected does not work. |
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| Converter overheats. |
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8. Specifications
| Feature | Specification |
|---|---|
| Model | STU-3000 |
| Input Voltage | 110V / 220V AC (selectable) |
| Output Voltage | 110V AC, 220V AC, 5V DC (USB) |
| Rated Power | 3000 Watts |
| Power Source Type | AC |
| Item Weight | 8.5 kg (18.7 lbs) |
| Power Cord Length | 3 feet |
| Recommended Use | Vehicle, Home, Office |
| Dimensions (L x W x H) | Approx. 23cm x 19.3cm x 15.3cm (9.06in x 7.6in x 6.02in) |

Figure 6: Dimensions of the STU-3000 voltage converter.
9. Support and Contact
For further assistance or inquiries regarding your OUKANING STU-3000 voltage converter, please refer to your purchase documentation or contact the retailer where the product was purchased. Please have your model number (STU-3000) and purchase date available when contacting support.