TCO: Asphalt and Shingle

TCO: Asphalt and Shingle

Application: Compressor
Motor Type: AC Induction
Manufacturer: Reliance
HP: 300
Voltage: 460
RPM: 3600
Enclosure: TEFC

Problem
A shingle company in Minnesota uses their compressor motor 24/7 to provide asphalt to the shingle plant and tank trucks. In one year, the company experienced two costly failures and decided to send the failed motor to IPS for analysis and repair.

Solution
During removal and initial inspection of the motor at the shop, IPS technicians observed the following:

• Elevated ambient temperatures where motor was installed
• Per the motor’s name plate, there were 4000 lbs. hanging from the C-Face
• Damaged bearing fits – Drive End (DE) and Opposite Drive End (ODE)
• Short radius of stator coils as they exited the stator slot
• Winding failure to the ground where the coil exits on the DE

After root cause analysis, IPS determined vibration, along with short coil radius, had resulted in the catastrophic failure. We rewound the motor with a lap winding using Class H materials, including the use of thicker 5-10-5 slot liner and VPI with an additional overdip to stiffen the coil extensions.

Additionally, IPS installed heat stabilized bearings with a C4 fit, and RTDs into the winding, as well as providing a jack to reduce the vibration by supporting the motor. Fans were also added to the compressor room to cool down the ambient temperature.

Savings
• The IPS rewound motor has operated reliably for almost 2 years without incident
• Prior to IPS, the motor had been rewound twice in the same year by the compressor OEM at a
cost of $35,000 each time. Not only was IPS’s rewind less costly, it also reduced the prior year Total
Cost of Ownership (TCO) by $211,698.

Download the complete case study and calculations below:

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