Description

UNI-T UTP3303-II Linear DC Power Supply 3CH 335W 32V Adjustable Dual Channel and Fixed Single-Channel Output

 

UNI-T UTP3303-II front and rear panel

figure: UNI-T UTP3303-II 

1) Models: UTP3303-11/3305-11.
2) Voltage display of CH1.
3) Voltage display of CH2.

4) Indicator of CH3, will turn red if the load current exceeds the rating value.
5) Power switch: press to power the instrument on or off.

6) CH1 voltage positive output terminal (red).
7) CH1 voltage negative output terminal (black).
8) Ground terminal (GND green).
9) CH2 voltage positive output terminal (red).
10) CH2 voltage negative output terminal (black).

11) CH3 voltage positive output terminal (red).
12) CH3 voltage negative output terminal (black).
13) CH2 voltage adjustment knob, which is to adjust the output voltage.
14) OUTPUT button, press it to enable output mode.

15) OUTPUT indicator, green indicates the output mode.
16) CH2 current adjustment knob, which is to adjust the output current.
17) Series/parallel mode buttons.
18) CH1 current adjustment knob, which is to adjust the output current.
19) CH1 voltage adjustment knob, which is to adjust the output voltage.
20) Current display of CH2.

21) Current display of CH1.
22) CC/CV indicator of CH2.
23) CC/CV indicator of CH1.
24) Power supply input interface.
25) Input voltage switcher.
26) Cooling fan outlet.

Main Features of UNI-T UTP3303-II

• High-precision 4-digit voltage and current display 10mV/1mA.
• Multi-turn potentiometer set voltage and current value.
• Temperature-controlled fan.
• Protections of OVP, OTP and reverse polarity.
• voltage preset value function.

UNI-T UTP3303-II’s Operation

WARNING

•  Before connecting with AC power source, please select corresponding voltage scale by AC SELECTOR on rear panel, and then check if the fuse specification matches the requirement of scale.
•  Connect the protective ground terminal to the ground.

 

• Boot Inspection

•  Adjust the current knob clockwise to the maximum.
•  Turn on the AC power source switch, the screen and CV indicator will be lightened.
• Adjust the voltage knob counterclockwise to the minimum OV, and then turn clockwise to adjust the output voltage to the maximum.
• Press the OUTPUT button to enable the output of power supply, adjust the current knob counterclockwise to the minimum, and then adjust the knob clockwise to the maximum. This is to ensure the current value can be adjusted to maximum rated value from 0.

• Operation of Constant Voltage

Operate constant voltage mode (CV mode) as steps below:

•  Power the instrument on, adjust the voltage knob to output voltage (open circuit), then the CV indicator should be lit up.

 

•  Adjust maximum output of current (current limit). In actual operation, if the current exceeds the limit due to load change, the instrument will automatically switch to the constant current mode, and the ratio of output voltage will drop.

• Operation of Constant Current

Operate constant current mode (CC mode) as steps below:

•  Adjust the current knob counterclockwise to the minimum, ensure the output current is OA, and power the instrument on.

 

• In no-load connection, adjust the maximum output of voltage (voltage limit) as certain load condition. In actual operation, if the voltage exceeds the limit due to load change, the instrument will automatically switch to the constant voltage mode, and the preset voltage limit and the ratio of output current will drop.

 

• Press the OUTPUT button to output DC voltage.

 

• Independent/tracking mode

 

 Independent mode, series tracking mode and parallel tracking mode can be switched by 2 buttons (series/parallel mode buttons) as steps below:

figure: UNI-T UTP3303-II button modes.

• In independent mode, if both the buttons are released (OFF INDEP), CH1 and CH2 are independent from each other.
•  If the upper button is pressed (ON SERIES), and the lower button is released, the instrument enters series tracking mode.

Voltage outputs from CH1 positive output terminal (red) and CH2 voltage negative output terminal (black), and the settings of parallel voltage and current can only be adjusted by CH1. Total voltage is the CH1 voltage plus the CH2 voltage, and the current is equal to CH1 current.

 

•  If both the buttons are pressed (ON PARALLEL), the instrument enters parallel tracking mode.
  At this time, CH is the positive output terminal of parallel, and CH- is the negative output terminal of parallel. CH1 is main channel and CH2 is slave. Parallel voltage and current can only be adjusted by CH1. Total parallel voltage is equal to the voltage of CH1, total parallel current is the CH1. current plus the CH2 current. In the no-load condition, it is normal when non-return to zero (NTR) appears.

 

• When the temperature of transformer reaches set value, the internal temperature switch will be disconnected. The instrument will be operational if the temperature drops, and the switch connects again.

General Maintenance tips for UNI-T UTP3303-II

WARNING

The maintenance instruction is only for the qualified maintenance personnel. To avoid electric shock, no maintenance outside the instruction is allowed.

UNI-T UTP3303-II Fuse Replacement

If the fuse is blown, CV indicator can’t be lit up and the power supply fails to run. Confirm the cause of the blown fuse before replacing the fuse, correct the problem, then replace the fuse by a same one as specifications.
Factory-prepared spare fuse is in the input socket of rear panel.

A WARNING

To prevent fires, only replace with fuses that meet the model and rating value. Do not connect the AC power source before replacing the fuse to avoid electric shock.

 Voltage of Power Source

The product allows voltage of AC110V/120V/220V/230V 50/60Hz, but the voltage scale should consist with output voltage.

•  Make sure the power source cable is disconnected.
•  Adjust the voltage switch to the required scale to meet various requirements.

 

figure: UNI-T UTP3303-II/UNI-T UTP3305-II requirements illustration 

package included:

1 X UNI-T UTP3303-II power supply.

Electra