LOTOS LT5000D, Manual

®

Faults

Possible Causes/Solutions

1. The power pilot light is off,  

    the fan doesn’t work, and   

    there is no cutting voltage 

    output.

1. The power switch is broken.

2. There is no electrical power.

3. The input cable is short-circuited.

2. The power switch is on,  

    the fan doesn’t work. No  

    voltage is indicated on the 

    front panel.

1. There is an improper connection to the plug or the plug is

improperly connected to the 380V power supply, causing over-voltage 

protection. For latter case, wait for 8 minutes, reconnect to 220V power 

supply, and restart the machine.

2. The transformer is broken.

3. Voltage deficiency protection has been activated.

4. The wire from the switch to the bottom board has loosened. Tighten it.

5. The relay on the bottom board is damaged. Replace with a new relay.

3. The fan is on, the 

    abnormal pilot light is not 

    on, cannot start the arc.

Contact the manufacturer or certified service personnel.

 4. The abnormal pilot light is 

     off, no cutting voltage 

     output.

1. The welding cable is broken.

2. The ground is improperly connected to the work piece.

3. The “+” output terminal is not properly connected.

5. The problem pilot light is 

    not on.

1.  The nozzle is oxidized or too far away. Remove the oxidization on 

     the surface, or shorten the distance to 1 mm.

2. Otherwise, contact the manufacturer or certified service personnel.

6. The abnormal pilot light is 

    on.

1. Over-current protection may have initialized. Either wait for 2 or 3 

minutes for the problem to go away, or turn off the power, wait until 

the abnormal pilot light is off, and restart (machine will recover  

automatically).

2. Otherwise, contact the manufacturer or certified service personnel.

7. The output current is not

    stable.

1. Check connections on the front panel.

2. Otherwise, contact the manufacturer or certified service personnel.

8. The machine does not cut   

    metal properly, or the arc is   

    not stable.

1. The input voltage is too low.

2. The ground cable is not well-connected.

3. The air pressure is too high or too low.

4. The nozzle and electrode of the torch do not fit well, or the input

current is too low.

14

The following trouble shooting guide is for your reference only. Lotos Technology will NOT take any 

liability or responsibility for any injury or damage caused in such action(s). Always turn off electrical 

power and air supply before performing inspection and reconnection.

CAUTIONS:

 Only qualified technicians are authorized to undertake the repair of this equipment in the 

case of machine failure.