TCO: Paper Manufacturing

TCO: Paper Manufacturing

Application = Refiner
Motor Type = AC Induction
Manufacturer = GE
HP = 5000
Voltage = 6900
RPM = 1200

Problem
A newsprint paper mill in the Northwest US has 36 refiner motors in operation. These motors
are commonly pushed beyond their 5000 HP rating, which has resulted in multiple failures and costly
unplanned downtime. The motor OEM has recommended that the mill rewind their refiner motors to
uprate them to 5620 HP. Unfortunately, several of the OEM rewinds have failed prematurely.

Solution
IPS rewound all 36 refiner motors with its proprietary PowerSeal® medium-voltage, global VPI engineered insulation system. IPS engineers custom designed the stator coils to deliver the following benefits:
• Motor uprate from 5,000 HP to 5,620 HP
• 3% increase in motor efficiency from 90% to 93%
• The PowerSeal rewind includes a standard 5-year warranty and the following reliability upgrades:
• Designed circuit rings to eliminate the leads from being connect on the end of the stator to allow for easier replacement of leads and to run cooler
• Eliminated the rigid mounting of the support rings back to the stator frame to allow thermal expansion of the coils to be independent from the frame
• Used surge rope and steel surge rings with felt blocking to allow for a rigid setup and ample cooling
• Tig welding of lamination finger supports to keep them in place during operation

Savings
The newsprint paper mill has experienced almost $500,000 in annual savings or over $3,400,000 in total savings over the past 7 years.
• Initial rewind cost – IPS PowerSeal rewind is approximately $35K cheaper than the OEM offered rewind
• Unplanned downtime – Unlike the OEM rewinds, the IPS PowerSeal rewinds have experienced no failures, thus eliminating unplanned downtime conservatively estimated at $10,000 per hour
• Motor efficiency gain – IPS PowerSeal stator coils were custom designed with more copper which resulted in a cooler running motor with a 3% efficiency gain, thus decreasing the annual power bill for running refiner motors by an estimated $43,468 each.

Download the complete case study and calculations below:

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