LZS power replacement and troubleshooting

When a larger current or higher voltage is required, two or more LZS-A1000-3 power supplies can be used in combination.

5.1 Parallel operation (Figure 6)

Purpose: To increase the total output current. For example, two parallel devices can obtain 84 A (24 V).

Connection method: Connect the positive and negative poles of each power supply in parallel. At the same time, pin 5 (current sharing bus) on the "D" connector must be connected. Pin 5 of all parallel units should be connected together.

Current sharing accuracy: within 10% of the rated current at 60 ° C.

Attention: It is recommended to use a power supply with the same model and output voltage setting. The output terminal can be grounded or floating. The total output current after parallel connection cannot exceed the sum of the rated values of each unit.

5.2 Serial Operation (Figure 7)

Purpose: To increase the output voltage. For example, two units connected in series can obtain 48 V (maximum 58.8 V).

Connection method: Connect the negative output of the first device to the positive output of the second device. The total output voltage is the sum of the two.

Attention: After series connection, the overvoltage protection of each power supply should be set independently. The load should not exceed the rated current of any power source. When connected in series, the output current is limited by the unit with the minimum rated current.

Common troubleshooting guide

6.1 No output from power supply

Possible causes, inspection methods, and solutions

The input voltage is missing or too low. The measured AC input terminal voltage should be 85-265 V. Check the upstream circuit breaker, fuse, and wiring

Remote shutdown is disabled. Check the position of the "OUTPUT ENABLE" switch (LOCAL/REMOTE); Measure the voltage of pins 6-7 of the "D" connector. If using remote, ensure logic 1; If remote is not used, turn the switch to LOCAL

Output overload or short circuit disconnect the load, measure whether the output is restored, and check whether the load has a short circuit; Reduce load current

Overvoltage protection triggers measurement to determine if the output voltage exceeds the OVP set point; Check if the OVP potentiometer has been mistakenly adjusted to adjust the OVP to the appropriate value (higher than the normal output voltage)

Overheating protection check whether the ambient temperature exceeds 70 ° C; whether the fan rotates to improve ventilation, reduce ambient temperature, and clear the fan filter screen

Internal fault: The red light is constantly on and there is no output. Return to the manufacturer for repair

6.2 Unstable or low output voltage

Possible causes, inspection methods, and solutions

Monitoring for excessive input voltage fluctuations and using a regulated power supply for AC input

Load transient change inspection: Increase the load change rate by increasing the output capacitance or using a higher power supply

Remote sensing wiring error or open circuit check if+S/- S is reliably connected. If using local sensing, ensure jumper installation

Output voltage adjustment potentiometer drift measurement voltage, try readjusting with a screwdriver to fine tune the potentiometer

6.3 The green "Output Good" LED is not lit but the output is normal

Possible reason: The output voltage is lower than 95% of the set value (for example, the adjusted voltage is 18 V, while the set value is 24 V). Check if the actual output voltage is consistent with the set value. It may also be in a remote shutdown state (the LED will also turn off).

6.4 Red "Fault" LED on

Meaning: overvoltage, overheating, or overcurrent shutdown, or output below 95% of the set value, or remote disabling.

Solution: First check for overload, high temperature, or OVP false triggering. Disconnect the load, cool down and restart. If the LED is still on and there is no output, it may be internally damaged.

6.5 Poor current sharing during parallel operation

Check if pin 5 of all units is reliably connected.

The output voltage of each unit should be adjusted to be consistent (within a difference of 20 mV).

The impedance of the load line should be matched as much as possible.

Maintenance and lifespan extension suggestions

Regular cleaning: Dust accumulation on fans and heat sinks can cause overheating. Use low-pressure compressed air for blowing.

Check the fan: Variable speed fans may run at low speeds under light loads, but should accelerate under heavy loads. Listen for any abnormal noise.

Tighten terminals: Vibration environment may cause loose wiring, check the input/output terminal torque once a year.

Replacement cycle: The lifespan of electrolytic capacitors is shortened at high temperatures. If the power supply has been running continuously for more than 5 years, it is recommended to replace it in a planned manner. The LZS series offers a 5-year warranty, but the actual lifespan depends on the environment.

Spare parts strategy: For critical systems, it is recommended to backup at least one power supply of the same model to shorten downtime due to malfunctions.

Precautions for Replacement with Old Model LZS-1000-3