Introduction
Interrupters are a crucial tool in the cathodic protection world. These devices are installed in series to the power circuit and allow technicians collect instant off potentials. There are different devices, manufacturers, and methods to obtain, install, and use these tools; however, their end goal is still the same from usage.
In this delicious article, I will explain the step by step procedure of how I install an interrupter inside a constant voltage rectifier ON THE AC SIDE. Before beginning anything inside a power source, always check with your company’s SOPs and requirements regarding safety measures and guidelines. Safety always remains a top priority.
Tools Needed For The Task:
Calibrated multimeter and half cell.
Current interrupter (There are different brands and types. Choose the type for your application.)
Here’s the interrupters we use at RCS:
Possibly a nut driver w/ nuts and bolts. (We’ll get to that later)
Step by Step Instructions - I won’t let you fail.
Put on all necessary PPE. This is definitely the most crucial step. I will always hound this to anyone.
Prior to opening or touching the rectifier, read the AC voltage of the cabinet. This needs to be less than 15VAC. You don’t want to die before installing that cool interrupter.
Once VAC is verified, open the cabinet. Using your multimeter, clip one lead to a stud on the Coarse side of the tap settings (avoiding where the buss bar is installed) and clip the other lead to a stud on the Fine side and read on VAC. You're looking for a range for the power supply to power the unit.
In my experience, I've used American Innovations' interrupters, and they have a range between 8-24VAC. Always confirm the threshold of your unit prior to usage. Failure to do so could result in mass worldwide destruction.
Story time - I once didn't ensure I was within the limits of a unit, because I was in a rush. Shortly after energizing the rectifier, I noticed a burning smell once I was closing the cabinet. Further investigation showed I melted the bottom of the interrupter. LOL! So, please pay attention.
Power down the unit. Remove the bussbar from the Fine side and place one interrupter lead where one bussbar connection was and the other lead on the center Fine stud.
Clip the power cable at the predetermined Coarse & Fine locations selected on Step 3.
Install/Screw in the GPS antenna cable. MAKE SURE GPS ATENNA HAS A CLEAR VIEW.
With all hands out of the unit, connections tight and secure, and nothing touching each out to cause a short, power on the unit.
Allow the interrupter to collect a GPS prior to setting the desired interruption cycle.
Multiple interrupters need to be synchronized with GPS to allow to accurate on/offs for collecting readings. Otherwise, they will be interrupting at random times at whenever you set them.
Once interruption is set on the unit, ensure the unit is getting all the current off in the OFF cycle by reading across the shunt in mV DC.
Time to go have fun with your corrosion plans.
Random Pieces of Information:
Bonds or mag protected structures can also be interrupted by using a battery as a DC power source. The installation is very similar to a rectifier.
Bonds or mag protected structures can also be interrupted by using a battery as a DC power source. The installation is very similar to a rectifier.
Check a waveprint on an Allegro to ensure all interruption is synchronized. A unit out of sync will create a "stair step" illustration on the graph.
You can also install the interrupter on the positive output leg.
Installing in the positive leg: The power connection procedure remains the same. This is where the nut driver comes into play. Remove the positive cable, install one interrupter lead where the positive cable was, and install the other lead with the positive cable.
Wrapping It Up:
Interrupters are a crucial tool necessary for collecting ON/OFF voltage potentials in the CP realm. There's many different brands, settings, and applications for them, so please take time to learn your system, preferred way, and what you need out of them. Stay safe, and as always, let me know if I can ever help out.