Electrode holders deliver power from the bus tube to your electrode stick. They're one of the most common failure points and should be monitored with care. Cleaning electrode holders should be incorporated into every mill's schedule.
Electrode Holder Inspection
1) Dirt and Buildup
An electrode holder must have a good connection with an electrode stick to prevent arcing. Dust and buildup usually gathers on the surface of electrode holders, and graphite from the electrode during slipping also gathers on the electrode holder surface. Debris on the contact surface of the holder creates an insulative barrier and results in arc burning. Perform routine cleanings with tools such as wire brushes and portable sand blasters to keep the surface clean.
2) Arc Damage
Arc damage is a result of dirt and buildup or poor clamping pressure. Arcing is often seen as pitting and gouges within the electrode holder’s contact surface. Furnace operators may also witness flashing as a result of arc burns during use. Visually check your holders for arc burns during each cleaning cycle. Arc burns are indicative of a failing holder and will likely become more sever with use. Severe arcs will burn through to the water channels and cause leaking. Experienced companies such as Erie Copper Works can repair holders at a fraction of the cost of new replacement holders when arc burns are discovered in a timely manner.
3) Back Arc Damage
A gap between the pad and arm head creates damage between the mating head of the arm and pack of the contact pad. Ensure the back of the pad is clean before installing. During installation, check for a tight connection between both copper surfaces; no gaps should be visible. Tighten the hardware to secure the pad based on the OEM’s specifications. The seals should compress and NOT interfere with the mating of the two surfaces. Use a shim to probe for gaps after the pad is connected. If you find arcing on the backside of a pad we can repair both your arm’s head and the contact pad.