CUTSFORTH's Online Truing FAQs
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How do I know if my collector rings/commutator would benefit from CUTSFORTH's Online Truing?
When you experience excessive brush vibrations (> 6 Mils), arcing, grooving, or photographing (also called imaging, ghosting or footprinting) on your ring or commutator. One or more of these issues likely makes your collector rings a good candidate for Online Truing.
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How long has CUTSFORTH been performing Online Truing?
Our company has performed our Online Truing process on hundreds of rings and commutators over the last 19 years.
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How safe is Online Truing for collector rings and commutators?
We have never had a serious injury in any plant.
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How much time does it take CUTSFORTH to perform the Online Truing process?
The time varies from a 2-10 hours depending on the condition of the collector rings or commutator.
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Do we need to reduce the load on our generator when the Online Truing service is in progress?
No, this is not necessary. The Online Truing process can be safely performed at full load.
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How do CUTSFORTH techs know what the run-out is when the ring is at full speed?
Our service techs measure the movement of the brush with a vibration analyzer in mils displacement. Basically, a round ring will register a low reading (generally < 2 mils) and an out of round ring will register high readings (> 6 mils is over the OEM recommended limit).
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Is the Online Truing really as accurate as other machining processes?
The process is often more accurate at creating a round surface because the work is performed on the generator while at normal operating speed and temperature. A round ring on turning gear does not always equal a round ring online.
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How do I know if my collector ring has enough life left for Online Truing?
As long is there is still a helical groove, it can be trued.
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Should I be concerned about our unit being tripped during this process?
The biggest risk of tripping a unit comes from the ground detection system. Service techs will inspect and monitor the unit for oil contamination and the collection of particles to avoid alarming the ground detection system. In rare cases, if the oil film is severe enough, they may choose to not proceed with the process until the oil leak is resolved. Cutsforth has tripped < 0.1% of the units it has performed Online Truing on over the past 20 years.
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How much lead-time does Cutsforth need to schedule Online Truing?
If you believe your unit is in an emergency state, we can usually respond within 24 hours for an expedited charge. If your unit can wait, we will work with your plant to schedule it in a timely manner.
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Who can perform this service?
All of our field service technicians are experienced and capable of performing Online Truing at your plant.
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What if I discover that the spiral groove in the collector ring is missing in places?
No problem! If tolerances allow, Cutsforth can restore the spiral groove at your next scheduled outage. Most collector rings are able to be re-grooved once in their lifetime. The minimum recommended depth of a helical groove is 0.03".