Longwei PS Series Adjustable DC Stabilized Power Supply

1. Introduction

The Longwei PS series adjustable DC stabilized power supply is a high-precision, high-reliability, single-channel output power source designed for a wide range of applications including laboratories, aging tests, mobile phone repair, educational institutions, and production lines. It features continuously adjustable output voltage and current between 0 and its nominal values, along with low ripple and low noise characteristics.

This manual provides essential information for the safe and efficient operation of your Longwei PS series power supply. Please read it thoroughly before use.

2. Safety Information

To ensure safe operation and prevent damage to the unit or injury to yourself, please observe the following safety precautions:

• Always connect the power supply to a properly grounded outlet.
• Do not operate the unit in wet or damp conditions.
• Ensure proper ventilation; do not block the cooling fan or vents.
• Do not open the casing; there are no user-serviceable parts inside. Refer servicing to qualified personnel.
• Verify the input voltage setting (110V/220V) matches your local power supply before connecting to mains power.
• Avoid short-circuiting the output terminals.
• Disconnect power before making any connections or adjustments to the output terminals.

3. Product Overview

3.1 Front Panel Controls and Indicators

• Current Display: Digital display showing the output current in Amperes (A).
• Voltage Display: Digital display showing the output voltage in Volts (V).
• Current Coarse/Fine Adjustment (CURRENT FINE/COARSE): Knobs to adjust the output current limit. 'COARSE' for large changes, 'FINE' for precise adjustments.
• Voltage Coarse/Fine Adjustment (VOLTAGE FINE/COARSE): Knobs to adjust the output voltage. 'COARSE' for large changes, 'FINE' for precise adjustments.
• Power Switch (ON/OFF): Main switch to turn the unit on or off.
• Output Switch (STOP/OUT): Controls the output power to the terminals. Allows interruption/start control without cutting main power.
• Output Terminals (Positive, Negative, Ground): Connections for your load. Red for positive (+), Black for negative (-), Green for ground (GND).

3.2 Rear Panel Features

• Cooling Fan: Provides necessary cooling for internal components. Ensure it is not obstructed.
• Input Voltage Switch (110V/220V): Selector switch to match the local AC input voltage.
• AC IN Socket: Connection point for the main power cord.
• Fuse Box: Contains the protective fuse for the unit.

4. Setup

1. Unpacking: Carefully remove the power supply from its packaging. Inspect for any signs of damage.
2. Input Voltage Selection: Locate the input voltage switch on the rear panel (Figure 2). Ensure it is set to match your local AC mains voltage (110V or 220V). Incorrect setting can cause severe damage to the unit.
3. Power Connection: Connect the provided AC power cord to the AC IN socket on the rear panel and then to a grounded wall outlet.
4. Initial Check: Before connecting any load, ensure the output switch on the front panel is in the 'STOP' position.

5. Operating Instructions

5.1 Basic Operation

1. Power On: Flip the main Power Switch to 'ON'. The digital displays will illuminate.
2. Pre-setting Voltage and Current:
   • With no load connected and the output switch in 'STOP', adjust the VOLTAGE COARSE and FINE knobs to set the desired output voltage.
   • To set the current limit, temporarily short the output terminals (use a suitable wire, but only for a brief moment to observe the current limit). Adjust the CURRENT COARSE and FINE knobs to set the desired maximum current. Alternatively, some units allow current limit setting without shorting by observing the current display when the voltage is set to zero and then increasing current.
3. Connecting the Load: Connect your device or circuit to the output terminals. Ensure correct polarity: positive (+) to red, negative (-) to black. The ground (GND) terminal can be used for chassis grounding if required.
4. Enable Output: Flip the Output Switch to 'OUT'. The power supply will now deliver the set voltage and current to your load.
5. Monitoring: Observe the voltage and current displays to ensure stable operation.
6. Power Off: Before disconnecting the load, flip the Output Switch to 'STOP', then turn off the main Power Switch.

5.2 Constant Voltage (CV) and Constant Current (CC) Modes

The Longwei PS series automatically switches between Constant Voltage (CV) and Constant Current (CC) operating modes:

• Constant Voltage (CV): When the load resistance is high, the output voltage remains constant at the preset value, and the output current is determined by the load.
• Constant Current (CC): When the load resistance is low (or a short circuit occurs), the output current remains constant at the preset limit, and the output voltage drops accordingly. This protects both the power supply and the connected load.

6. Specifications

6.1 General Performance

• Input Voltage: 110V/220V AC (selectable)
• Operating Modes: Constant Voltage (CV), Constant Current (CC)
• Protection: Current limiting protection, no burnout at full load.

6.2 Voltage Characteristics (Constant Voltage State)

• Load Stability: ≤ 0.01% + 5mV
• Recovery Time: ≤ 100μs
• Ripple Noise: ≤ 1mVrms
• Temperature Coefficient: ≤ 300PPM/°C

6.3 Current Characteristics (Constant Current State)

• Current Stability: ≤ 0.2% + 3mA
• Load Stability: ≤ 0.2% + 3mA
• Ripple Noise: ≤ 3mArms (RMS value)

6.4 Model Specifics

7. Maintenance

• Cleaning: Use a soft, dry cloth to clean the exterior of the unit. Do not use abrasive cleaners or solvents.
• Ventilation: Regularly check that the cooling fan and ventilation openings are free from dust and obstructions.
• Fuse Replacement: If the unit fails to power on, check the fuse in the fuse box on the rear panel. Replace with a fuse of the same type and rating only.
• Storage: When not in use for extended periods, store the power supply in a cool, dry place, away from direct sunlight and extreme temperatures.

8. Troubleshooting

• No Power:
  • Check if the power cord is securely connected to both the unit and the wall outlet.
  • Ensure the main Power Switch is in the 'ON' position.
  • Verify the input voltage switch on the rear panel is set correctly (110V/220V).
  • Check and replace the fuse if blown.
• No Output Voltage/Current:
  • Ensure the Output Switch is in the 'OUT' position.
  • Check if the voltage and current adjustment knobs are set to non-zero values.
  • Verify the load is correctly connected and not open-circuited (for current) or short-circuited (for voltage).
• Overheating:
  • Ensure the cooling fan and vents are not obstructed.
  • Reduce the load if the unit is operating continuously at its maximum capacity in a high ambient temperature.

9. User Tips

• Continuous Operation: The PS series is designed for continuous use for up to 24 hours, making it suitable for extended testing or production runs.
• Full Load Protection: The built-in current limiting protection ensures that the unit will not burn out even when operated at full load, providing reliability and peace of mind.
• Precise Adjustments: Utilize both the COARSE and FINE adjustment knobs for voltage and current to achieve highly precise settings required for sensitive applications.

10. Support

For technical assistance or inquiries, please contact your vendor or the manufacturer directly.

Email: aa13874080369@163.com

WhatsApp/WX/Phone: +8615717403997