February 2022 - Bleiswijk, The Netherlands
Emergency power engineer Eric Koudijs recently discovered that more is not always better during a challenging job at greenhouse vegetable exporter Haluco.
Ever since 2007, the packaging and distribution site in Bleiswijk has a distribution panel with a control made by emergency power control specialist Wageningen Electronics, which has been part of Elektro Internationaal since 2008, where engineer Eric Koudijs ’manages’ the emergency power control department. He received a report from Slagboom Installatiebedrijf that one of the two PLCs in the control system no longer worked after 14 years of loyal service. ”About half of the company was left in the dark,” Eric says. ”I went to Bleiswijk and switched off the controls. After that we were able to manually switch the main back on. Haluco was able to resume all activity. But of course the real work had yet to begin. The emergency power supply no longer worked due to the failure of the control system.”
Controls made ’nicer’
Eric made an offer to refurbish the emergency power control. He explains: ”I was allowed to carry out my plan to provide the two new PLCs with adapted programming and to replace a large part of the functional (wearable) components. I revised the programs of the PLCs by drawing up a sketch of the situation as desired by the customer, combined with our many years of expertise. I immediately made the controls a bit ’nicer’. There were some unlikely twists and turns in the original software, which I left out. You often see that when you start with a test set-up, the worst-case scenarios can get a bit out of hand here and there. After approval from the customer, I programmed my final ’if-then structure’ and extensively tested it in the test room of Elektro Internationaal.”
Open heart surgery
In the end Eric, together with service technician Mario de Jong, installed the controls and components on location on a Friday, while everything remained in operation. “A kind of open heart surgery. And the patient is doing well,” Eric laughs. ”On Saturday, the customer was able to switch its IT activities to another location, so that they could continue as usual. Production was suspended, which allowed us to disconnect the mains power to test the complete installation and control. So we could switch to our heart’s content. The test was successful. Everyone was very pleased.”
Too much of a good thing
Until Eric received a phone call that the exact same transformer switch had failed and that it could not be switched on manually. Eric: ”Obviously the ’suspicion’ rested on the PLCs, because it looked like we hadn’t solved the problem. I then performed a diagnostic by phone. By asking the right questions, we arrived at the voltage level. It was at a whopping 265 Volts! The other transformer also had such a high incoming voltage across all phases. And of course that couldn’t be good. I also asked to check with a good voltage meter whether it was actually this hig a value. And that indeed turned out to be the case. I advised to first ensure that the correct degree of voltage was present, before putting this way too high level back on the installation, with all possible harmful consequences. After inquiring with the regional network manager, the problem turned out to be in a defective transformer and a switch was made to a different power supply. A bang and a flash later, the voltage returned to teh correct level after 1.5 hours and the installation also switched back neatly. So our controls did their job neatly. Well, I like a bit of tension, but this was a case of too much of a good thing. Fortunately, I was able to help the customer discover and solve the problem.”
