ASPHALT & SHINGLEA Premium, Reliability-driven, Low-voltage Rewind

The Challenge A shingle company in Minnesota experienced two failures on their compressor motor in one year. These failures were costly to the plant as the compressor is used 24/7 to provide asphalt to the shingle plant and tank trucks. The facility sent the failed motor to IPS for analysis and repair. During removal and initial inspection of the motor at the shop, the following findings were observed and documented:

• Elevated ambient temperatures where motor is installed • Per motor name plate there is 4,000 lbs. hanging from the C-Face • Damaged bearing fits - Drive End (DE) and Opposite Drive End (ODE) • Short radius of stator coils as they exit stator slot • Winding failure to ground where the coil exits the slot on the DE

After performing a root cause, IPS determined vibration, along with the short radius of the coils, resulted in the catastrophic failure of the winding.

The Solution

IPS rewound the motor with a lap winding using class H materials. This included the use of thicker 5-10-5 slot liner, and VPI with an additional overdip to stiffen up coil extensions. Space permitting, IPS winders tried to straighten the coils where they exited the slot to limit side pressure on slot liner.(continued on back side...)

• Application = Compressor

• Motor Type = AC Induction

• Manufacturer = Reliance

• HP = 300

• Voltage = 460

• RPM = 3600

• Enclosure = TEFC

TCO CASE STUDY #7

Catastrophic failure of winding was caused by a combination of vibration and the short radius of coils exiting the stator slot

6010

100

500

5040

30

20

400

300

200

1,000

70 80 90 100 110 120 130 140 150 160 170 180 190

Total Winding Temperature — ºC

Magnet Wire Thermal Class Ratings

Avg

. Exp

ecte

d Li

fe —

Hou

rs (0

00)

CLASS HCLASS F

Expected Life Hours @ 120˚CExpected Life Hours @ 120˚C

1,000,000250,000

250,000

1,000,000

Class H magnet wire has 4X the average expected life hours of Class F magnet wire

www.ips.us www.ips.ca

TOTAL COST OF OWNERSHIP (TCO)

COST DESCRIPTIONIPS

SOLUTIONANNUAL

TCO

Unplanned Downtime (Plant)Total events (Qty. / Year)

Reduction in Capacity* ($ / Hour)Avg. time per event (Hours)

Sub-Total ($ / Year)

Total events (Qty. / Year)Avg. repair cost ($)

Sub-Total ($ / Year)

1st Year TCO =

IPS SOLUTION SAVINGS =

2

2

0

$160,000

8$10,000 $0

0

$0

$35,000 $18,3021

$70,000 $18,302

$230,000 $18,302

$211,698

COSTITEM

Repair

Prod

uctio

nM

ater

ials

The Solution (continued from front side...) As an additional measure to improve reliability, IPS also installed heat stabilized bearings with a C4 fit, and RTD’s into the winding. Once the motor was installed, IPS technicians provided a jack to reduce the vibration by supporting the motor. Fans were also added to the compressor room to cool down the ambient temperature.

The Savings The IPS rewound motor has operated reliably for almost 2 years without incident, eliminating all unplanned downtime and repair costs of the plant's compressor motor and missed production by the plant. 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.

The Conclusion IPS industry knowledge, engineering and repair specifications provided a quality solution for a reoccuring issue. Without the upgrades to this motor, the customer would have continued to fail motors and lose time and money.

www.ips.us www.ips.ca