Greetings! Today we have a problem with the waste oil incinerator. When starting the incinerator, the touch panel displays the error “Low voltage 220V”. The incinerator is not working. What kind of error is this and how to fix it, we will try to figure it out in the article.
We turn to the instruction manual and see that the “Low voltage 220V” error is associated with a low voltage of 220V in the control circuit.
Below is the “Troubleshooting list” from the manufacturer, which allows you to identify the problem and ways to solve it.
The voltage drops by 10% (or more) from the normal 220V. At the same time, the multimeter did not show any voltage deviations. It is possible that the PLC protection misunderstands the operating voltage and generates this error.
We also pay attention to the 440 / 220 / 24 V transformer, which, using 440V of the primary winding of the power circuit, transforms the voltage into 220V and 24V of the secondary windings of the control circuit.
Before drawing a conclusion about malfunction of the PLC or its power supply, let’s connect 220V for the control circuit from another power source (in my case, from the ship’s power outlet 220V). We connect, of course, through the F8 2A circuit breaker, which is used in the circuit for a 220 volts.
The circuit works and the incinerator starts without a low voltage error. This means we conclude that the problem is in the secondary winding of the 220V transformer. The transformer is old and it is possible that it cannot withstand the current load when starting the incinerator, so it will have to be replaced.
If a transformer is giving a low voltage output, there could be several potential reasons:
Overloading: If the load connected to the transformer exceeds its rated capacity, it can cause a drop in the output voltage.
Under Voltage Supply: If the input voltage to the transformer is lower than the rated input voltage, the output voltage will also be lower.
Internal Faults:
- Shorted Turns: Short circuits within the windings can reduce the effective turns ratio, lowering the output voltage.
- Open Circuits: Breaks in the winding can cause incomplete circuits, resulting in reduced or zero output voltage.
Poor Connections:
- Loose or Corroded Connections: Poor connections at the terminals can cause significant voltage drops.
- Faulty Wiring: Damaged or improper wiring between the transformer and load can also lead to voltage drops.
Magnetic Core Issues:
- Saturation: If the core becomes saturated, it cannot efficiently transfer the magnetic flux, leading to lower output voltage.
- Hysteresis or Eddy Current Losses: Excessive core losses can result in lower efficiency and reduced output voltage.
Temperature Effects:
- Overheating: Excessive heat can cause insulation breakdown and winding resistance increase, leading to lower output voltage.
Design or Manufacturing Defects: Errors in the design or manufacturing process can cause a transformer to not perform to its specified ratings.
External Influences:
- Harmonics: Non-linear loads can introduce harmonics, which can cause a reduction in the effective voltage.
- Environmental Factors: Extreme environmental conditions, such as moisture or chemical exposure, can affect transformer performance.
To diagnose the issue accurately, you would typically check the input voltage, load conditions, inspect the transformer for visible damage, and perform electrical tests such as winding resistance measurement, insulation resistance test, and possibly a turn ratio test.
We installed another transformer on the secondary 220V winding, a more powerful one, ordered the original transformer, and left the secondary 24V winding connected.
An old transformer with wires disconnected from the 220V secondary winding only works on 24V.
The new transformer was connected temporarily with a separate circuit breaker until the original trans arrived. The incinerator works without any problems.
Incinerator model: Kangrim KFB-32
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