How much damage can flux contamination cause?

Enough to kill a commutator.

When soldering coils into the risers of a commutator, the worst potential consequence is flux contamination, especially in solid riser comms. The same flux that cleans the copper to permit the solder to adhere uniformly to the risers creates a potential for contamination that can destroy a commutator. Flux contamination can occur during the soldering process when flux and/or excess solder seeps away from the riser slots and finds its way to the underside of the commutator. Because the flux and solder are conductive, they render the mica insulation useless. When the insulation can no longer prevent electricity from jumping from bar to bar, the commutator shorts out. Once the mica insulation is contaminated, almost nothing can be done to restore its insulating properties. When the commutator shorts out due to flux contamination, there are usually only two options: Reinsulate (replacing all mica insulation throughout the commutator) or rebuild.

When inspecting a commutator for flux contamination, look for discoloration of the copper bars. The discoloration may take several forms. Streaks of solder and flux are silver in color; carbon residue where arcing has occurred is black; contaminated copper bars can take on a darker, mottled and greenish coppery hue, or the contaminated area may just appear lighter than others. Compare the rear dovetail to the front, since the front will be free of contamination. As always, when taking a comm apart, be sure to band it tightly and bake it before attempting to remove the v-rings.

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There are several ways to reduce the risk of flux contamination during the soldering process:

• While soldering, angle the comm so that flux and solder run away from, and not toward, the bottom of the comm.
• Use flux and solder sparingly.
• Flux and solder small sections of the comm at a time.
• Use a rosin-core solder to reduce the need for flux, or a flux- based solder so the solder contains the flux.

If the commutator is contaminated, some solvents will clear minor contamination, but call your ICC representative at any time for advice on how to proceed.

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If you have any technical questions don't hesitate to call, we can talk you though the troubleshooting process. 865-983-7444

Our sincere gratitude.

We would like to thank our customers for their support, concern and flexibility during last week’s unfortunate train derailment and subsequent evacuation of our facility. There were no ICC employees injured and we are back in full production. Customers can expect updates on their jobs and if there was any impact to their specific job production or shipping.

A special thank you goes out to the Maryville, Blount and Alcoa first responders, volunteers, the local Red Cross and CSX emergency team for their swift reaction and tireless efforts to keep our community informed and safe. Your selfless acts have not gone unnoticed.  ICC had the privilege of working with CSX to set up a command post during the early hours of the incident and we were quite impressed by their policies and procedures for cleanup and their immediate attention to how this impacts local business and workers.

The Maryville community pulled their strengths and without hesitation helped their fellow community members, ICC is proud to call Maryville their home.     

Seamless Extension Banding Can Save a Commutator

When you band commutator extensions with skill and a few tricks of the trade, all seams are sealed and carbon won't infiltrate.  Preventing carbon from entering behind the copper bars, or between the mica v-ring and the steel can prevent problems with arcing bar-to-bar, as well as bar-to-ground.  The pressure used, technique applied, and finishing touches make a big difference.  A feeler gauge should not be able to enter a seam. If it can, your comm is at risk.  Contact us if we can help walk you through it the next time you have to replace a band. 

Nail down a procedure for replacing V-rings in house.

Replacing v-rings can be the answer to giving your customer's commutator new life, without having to resort to a refill. By firming up a procedure, you take the guesswork out of the process, and end up saving time and money on the repair. 

Following these steps will help you provide a tight comm, fully cured and ready for operation. 

"Gotcha's"

Overtightening: While the values provided may seem low, please use caution. If you have any questions, call ICC and we'll be happy to discuss your commutator specifically. Overtightening can bend the dovetails, resulting in bar movement, broken brushes, seized motors and overheated copper segment packs requiring re-manufacturing or replacement.

Insufficient Closings: The guidelines for thermal cycles are provided to ensure a tight, solid commutator. These closings allow for proper seating of the copper and mica segment pack to the steel, in addition to curing the mica v-rings.

Contamination: It will never be easy to get a good test on a unit that has been in operation, but a thorough cleaning is imperative to ensure proper operation once the commutator is reassembled.

Easy steps for flawless v-ring installation

1. Heat the commutator to 300°F, band it tightly using res-i-glas banding tape and cure.
2. Remove the caps.
3. Clean and sand the internal dovetail angles until the comm is free of all contamination.
4. Test bar to bar.
5. Carefully install new mica v-rings and assemble the unit to the steel.
6. Hand tighten all bolts or nut.
7. Heat commutator in oven to 375°F.
8. Remove from oven and torque hot to specifications in the chart shown in a star pattern.
9. Watch for even cap movement.
10. Cool to ambient temperature and torque again to specs.
11. Repeat heating and cooling cycle through two more cycles, torquing at each stage.
12. Test bar to bar and bar to ground.

*Disclaimer: ICC provides the above information in good faith but due to the wide range of quality of product and levels of experience, ICC is not responsible for the failure to achieve successful v-ring replacement through following the above instructions.