General Electric produced tens of thousands of Magne-Blast breakers in various sizes from the early 1950s through the 1970s.
Continued maintenance of the original air breakers or upgrading them with a vacuum retrofit has helped to extend the lifespan of this product line but there are other critical components in the switchgear that also need maintence and upgrading to maintain safety and overall reliability. Today we are going to address one of those components, the "Primary Disconect" more commonly known as the "Cell Bottles". This critical component consistes of three porcelain mounted on an aluminum base with copper conductors rising from the top in various configurations to meet the line or load side connections in the switchgear.
Why Magne-Blast Bottles Need to be Repotted
The element that we are addressing here is the old style "tar pitch" that was used to stabalize the riser buss and fill the void between the conductor and the bottle. This pitch ages and cracks over time with will not only allow dirt and moisture to enter the cracks but also tends to allow the spring loaded tulip inside to bottle to wiggle and misalign with the breaker and can be the source of more catastrophic failures or just a loose high resistance connection.

This illustration shows a typical set of bottles with one phase on the left "before" the middle phase "during" and the right hand phase after the upgrade is complete.
Those failures can be catastrophic, causing untimely loss of production and collateral damage, and can occur regardless of the care and maintenance of the breaker and the rest of the system. The question then is, “How do I maintain the reliability of this system”? Should I spend the capital for upgrades and replace the whole system?”
The answer is simple, reach out to National Power Equipment Inc. One of our specialties is repairing, upgrading and supplying replacement bottles that are upgraded with our proprietary 2 part epoxy for a true one and done solution.
NPE’s 8 Step Procedure:
- Examine the bottles in a fixture and conduct a wipe test to assure that they are candidates for rebuild.
- Remove the outdated “tar pitch” potting right down to the base filler.
- Align the connecting tulip and lock it in place so it doesn't move and cause future failures.
- Secure the joint between the copper and seal.
- Remove the olde buss insulation and insulate the buss with modern shrink tube insulation.
- Replace the old potting with a new 2 part system that is thermally stable which will last far into the future.
- Clean and silver plate all mating surfaces to increase conductivity at critical joints.
- Perform final tests in a shop fixture to ensure proper alignment and overall performance.
Sound simple? The devil is in the details and NPE focuses on details. This whole procedure may sound easy but there is typically little opportunity to schedule downtime to shut down production while these critical components are sent out for work which can take several weeks.
NPE stocks replacement bottles that can be matched to your system and swapped out in hours rather than weeks. Once we've provided identical replacements, we can evaluate the bottles that were taken out and either provide a credit for the "core" or we can recondition/repot them for replacement in other cells or return to inventory for future needs.
Either way it demonstrates our commitment to "The right part, at the right time, right now!"
Contact us online or give us a call at 216-898-2680 to discuss our Magne-Blast Bottle Repotting Program today.
