Maintenance

Sleeve Bearing – 500, 580, 680, 800 Frames Access to the motor interior can be gained by removal of the upper half of the horizontally split bearing bracket.

1.Remove the parting bolts at the horizontal split.

2.Remove the bolts at the outer circumference of the upper half of the split-bearing bracket.

3.Pull the upper bracket away from the face of the frame and remove bracket.

The entire procedure can be done without disturbing the bearing enclosure or coupling alignment of the motor to the load. The split-bearing capsule is held together by bolts.

Sleeve Bearing - 1120 Frames

Access to the motor interior can be gained by removal of the bearing bracket as follows:

1.Remove the parting bolts at the horizontal split.

2.Carefully remove the top half of the bearing housing by lifting it straight up and then pull it away from the lower half.

Air Deflector

Air deflector construction depends on the type and size of motor. The following conditions will be found when accessing the motor interior;

1.500 frame motors have air deflectors that are retained in the fit between the bearing housing and the stator yoke. Such air deflectors will be removed with the bearing housing or can be easily removed from the stator yoke after bearing housing removal.

2.580, 680, 800, or 1120 frame motors have air deflectors which are mounted with bolts to the stator yoke.

3.Air deflectors on sleeve bearing motors are horizontally split.

Cleanliness

The exterior should be kept free of oil, dust, dirt, water, and chemical. It is particularly important to keep the air intake and exhaust openings free of obstructions.

NOTE

If equipment is operated intermittently in very damp locations, it should be protected by space heaters. To retard corrosion, grease all machined fits when the unit is reassembled after a maintenance check.

Loading

Overloading causes overheating and reduces insulation life. A winding subjected to a 10°C temperature rise above the maximum limit for its class may have its insulation life halved.

Underloading a motor is improper as it lowers the motor power factor and efficiency which results in higher power cost.

Temperature

Electrical apparatus operating under normal conditions becomes quite warm. Although some places may feel hot to the touch, the unit may be within limits. If checking total temperature by winding resistance or imbedded detector (RTD), the total temperature should not exceed the following:

When operating at full load:

 

 

Class of Insulation System

 

 

B

F

H

Temp. by

All HP

120°C

145°C

165°C

Resistance

(248°F)

(293°F)

(329°F)

 

 

1500HP

130°C

155°C

180°C

 

or less

(266°F)

(311°F)

(356°F)

 

 

 

 

 

Temp. by

Over

 

 

 

1500HP

125°C

150°C

175°C

Embedded

-Under

(257°F)

(302°F)

(347°F)

Detector

7000V

 

 

 

 

Over

 

 

 

 

1500HP

120°C

145°C

165°C

 

-Over

(248°F)

(293°F)

(329°F)

 

7000 V

 

 

 

When operating at 1.15 service factor load:

 

 

Class of Insulation System

 

 

B

F

H

Temp. by

All HP

130°C

155°C

175°C

Resistance

(266°F)

(311°F)

(347°F)

 

 

1500HP

140°C

165°C

190°C

 

or less

 

(284°F)

(329°F)

(373°F)

 

 

 

 

 

 

 

Temp. by

Over

 

 

 

1500HP

135°C

160°C

185°C

Embedded

-Under

(275°F)

(320°F)

(365°F)

Detector

7000V

 

 

 

 

Over

 

 

 

 

1500HP

130°C

155°C

175°C

 

-Over

(266°F)

(311°F)

(347°F)

 

7000 V

 

 

 

These temperatures represent the maximum temperature for each class of insulation and include a 40°C ambient temperature. Operation above these temperatures will result in reduced insulation life.

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