Alignment of Two Bearing Generators{4450} Caterpillar

Alignment of Two Bearing Generators{4450}

Usage:

D353 (46B, 47B);
G353 (64B);
D375 (43B);
D379 (68B, 76B);
G379 (72B);
D397 (41B);
D398 (66B, 75B);
G398 (73B);
D399 (35B);
G399 (49C);
3508 (23Z, 70Z, 1ZF);
3512 (24Z, 67Z, 3YF);
3516 (25Z, 73Z, 4XF, 5SJ)

Introduction

This instruction shows the procedure for the cold alignment of two bearing generators to the above engines mounted on Caterpillar bases and using a Caterpillar viscous dampened coupling. This alignment procedure covers both generators driven from the flywheel (rear driven) and generators driven from the front of the engine crankshaft (front driven). Comments on special alignment situations (such as generator-to-generator driven, compound engines, the use of bases and couplings not manufactured by Caterpillar, etc.) are given on page 6.

Do not start the final alignment of the generator(s) until the base is in its permanent position, the engine(s) permanently installed on the base, and the initial alignment of the generator has been completed.

General Information

Cold Alignment

The cold alignment procedure described in this instruction is the recommended procedure for alignment of two-bearing generators to Caterpillar diesel engines. This procedure must be performed with all components at ambient temperature.

In order to achieve correct operating alignment, the following factors have been taken into consideration in determining cold alignment specifications:

1. During the cold alignment procedure, the crankshaft lies at the bottom of its main bearing bores. Under running conditions, firing pressures, centrifugal forces and engine oil pressure all tend to lift the crankshaft and cause it to rotate around the center of the main bearing bores.

2. The weight of the flywheel and coupling causes a small deflection of the shafts during the cold alignment procedure.

3. Engine heat causes the expansion of metal in the engine and generator during operation. The result of this expansion is a change in the locations of the centerlines of the crankshaft and generator shaft. Because the thermal expansion of the engine is greater than that of the generator, the change in the location of the horizontal centerline of the engine crankshaft will be greater than the change in location of the horizontal centerline of the generator shaft.

Because of the above factors, the cold alignment procedure positions the horizontal centerline of the generator shaft above the horizontal centerline of the crankshaft. Alignment of two-bearing generators using the cold alignment specifications on page 24 will result in correct alignment during operation.

Hot Alignment

In the past, a hot alignment check may have been used to check the accuracy of the cold alignment procedure. However, factory tests have shown that the results of the hot alignment check are inconsistent; therefore, this procedure is not recommended.

Indicator Readings

When taking indicator readings, always remember that a plus (+) reading means that the tip of the indicator moved into the dial indicator; a minus (-) reading means that the tip of the indicator moved out of the dial indicator.

When comparing two plus (+) indicator readings, the larger numerical reading is more than the smaller numerical reading. However, when comparing two minus (-) indicator readings, the larger numerical reading is less than the smaller numerical reading. In both cases, the indicator reading becomes less as the tip of the indicator moves out of the dial indicator.

The Total Indicator Reading (TIR) is the total amount of movement of the indicator needle. The TIR is always a positive value even though one or both of the readings are negative. For example: If the indicator reading varied from -10 to +5, the TIR was 15. If the indicator reading varied from -5 to -15, the TIR was 10.

Indicator readings are taken at four locations designated A, B, C and D as shown above. The dial indicator is always "zeroed" at location A before taking any readings. When taking readings, the indicator must be returned to Location A to make sure the indicator reading returns to zero. A quick way to check the validity of the readings is to remember that the the reading of B + D should equal the reading at C. This is valid where the driving and driven shafts are rotated together while checking alignment.

When checking the alignment of front driven generators, the indicator reading will be a negative value as shown above; however, this does not mean that the generator shaft is lower than the crankshaft. This occurs because the indicator mounting point is on the engine side of the coupling, thereby reversing the indicator reference point from that of rear driven generators. On rear driven generators, the indicator mounting point is on the generator side of the coupling.

Crankshaft End Play

Before taking indicator readings during the alignment procedure, always move the engine crankshaft to the end of its end play toward the front of the engine, and the generator shaft to the end of its end play toward the engine. Do not use force against the crankshaft or generator shaft while taking the indicator readings. After installation and alignment of the generator, the crankshaft end play must not be less than before the installation of the generator.

Types of Misalignment

Parallel or bore misalignment occurs when the centerlines of the driven equipment and the engine(s) are parallel but not in the same plane as shown above.

Face runout refers to the distance the face of the hub is out of perpendicular to the shaft centerline as shown above.

Angular or face misalignment occurs when the centerlines of the driven equipment and the engine(s) are not parallel as shown above.

Bore runout refers to the distance the driving bore of a hub is out of parallel with the shaft centerline as shown above.

Tools Needed

(1) FT1010 Alignment Yoke.

(2) FT1011 Alignment Bar.

(3) 1/2" Diameter × 12" long threaded rod with nuts.

(4) Adapters to mount dial indicators on alignment yoke (fabricate to fit dial indicators used).

(5) Starrett Dial Indicator Set No. 196 or Caterpillar 8S2328 Dial Indicator Group or equivalent. (The use of two dial indicators is recommended to facilitate final alignment).

(6) Caterpillar 6F6922 Depth Micrometer or equivalent.

(7) Starrett Dial Gauge No. 696 and Balancer Attachment 696B (Use to check crankshaft deflection if the engine and generator are installed on a base not made by Caterpillar).

Special Alignment Situations

Original Installation of Engine(s) And Generator(s)

The original installation of the engine(s) and generator(s) on the base requires accurate location and welding of the mounting blocks and supports. Because of the many possible engine, generator and base combinations, it is not practical to include original installation and alignment in this instruction. Use the engineering drawings and instructions provided with the specific engine, generator and mounting group to perform this part of the alignment procedure. After the base is in its permanent position, the engine(s) is permanently installed on the base and the initial alignment of the generator has been completed, use this instruction to perform the final alignment of the generator(s) to the engine(s).

Generator-To-Generator Alignment

To align a generator-to-generator arrangement, first complete the final alignment of the driving generator to the engine as shown in this instruction. Finally, align the driven generator to the driving generator. This alignment procedure is the same as generator-to-engine alignment but with one important difference. On generator-to-generator alignment, the centerlines of the generator shafts must be in line with each other. See the Specifications on page 24 for generator-to-generator alignment. Recheck the alignment of each generator after all generators have been aligned.

Compound Engine Alignment

The installation and alignment of an engine-engine-generator arrangement or engine-generator-engine arrangement requires not only accurate location of the engines and generator, but also a special timing procedure between engines. Use the engineering drawings and instructions provided with the engines, generator, coupling group and mounting group and the procedure shown in this instruction to install and align these arrangements.

Other Manufacturers Couplings

If a viscous dampened coupling not made by Caterpillar is used, it may be necessary to remove the flexible element from the coupling before performing final alignment. Some flexible elements not made by Caterpillar are "stiff" and prevent accurate alignment readings.

E Other Manufacturers Bases

NOTE: The following procedure is necessary only on D398, G398, D399 and G399 Engines. Six cylinder and V-8 cylinder engines do not require a crankshaft deflection test when used with a base not made by Caterpillar.

1 If the engine(s) and generator(s) are mounted on a base not made by Caterpillar, a crankshaft deflection test must be made after final installation of the engine(s) and before final alignment of the generator(s). The following procedure can also be used to check crankshaft deflection when using a Caterpillar base if there is doubt as to the accuracy of the engine installation.

2 Remove inspection cover from the side of the cylinder block to expose the crankshaft center throw. Turn the crankshaft in the normal direction of rotation until the counterweights on the center throw are just past the connecting rods. Install a Starrett Crankshaft Distortion Dial Gauge No. 696 with a No. 696B Balancer Attachment as shown. As a precaution, tie a string to the gauge and fasten it to the outside of the engine to facilitate retrieval should the gauge fall into the oil pan.

3 Zero the dial indicator. Make sure the indicator is seated properly by rotating it on its own axis until it will hold a zero reading. Rotate the crankshaft in the normal direction of rotation while recording the indicator readings at five positions (approximately 60° apart) through approximately 300° of crankshaft rotation.

4 Rotate the crankshaft backwards to its original position. At each point of observation, the reading must be the same as initially recorded. The indicator must also return to a zero reading at the original position in order to make a valid test. If the indicator did not return to a zero reading, the indicator shaft points were not seated and the test procedure must be repeated.

5 If the indicator reading was more than .001" (0.025) at any of the five positions, cylinder block distortion has occurred due to improper engine mounting. Loosen bolts (1) that fasten engine rails (2) to the mounting blocks (3) which are welded to the base. Install shims as necessary between rails (2) and blocks (3) to ensure that each mounting block (3) is carrying its portion of the load. Repeat the crankshaft deflection test.

Reinstallation of the Generator

NOTE: If a new coupling is being installed or if there is any doubt as to the specifications of the original components, check the individual components as shown on page 20 before installation of the generator.

1 Remove all dirt, burrs and paint from the mating surfaces of the generator and the generator support pads. Make sure the mating surfaces of the coupling, engine and generator are completely clean.

2 On front driven generators, install adapter (1), seals (2) and outer coupling (3) on hub (4) of the generator. Put 4L7464 Silicone Grease on the teeth and bore of coupling (3). Install rubber boots (5). Put silicone grease on the teeth and inside diameter of booths (5). Install inner coupling (6). Put the remainder of the 24 oz. (0.7 kg) of silicone grease in the coupling, and install plate (7). Install shaft (8) on the engine.

3 On rear driven generators, install seals (9) and outer coupling (10) on the flywheel. Put 4L7464 Silicone Grease on the teeth and bore of coupling (10). Install rubber boots (11). Put silicone grease on the teeth and inside diameter of boots (11). Install inner coupling (12). Put the remainder of the 24 oz. (0.7 kg) of silicone grease in the coupling, and install plate (13).

4 Put the generator in position on the support pads. Use the vertical and horizontal alignment screws on the generator to put inner coupling (12) or (6) in alignment with generator hub (14) on rear driven generators or shaft (8) on front driven generators. NOTE: On some bases, it may be necessary to weld plates (15) to the supports in order to install the horizontal alignment screws. Fasten inner coupling (12) or (6) to hub (14) or shaft (8).

5 Move the crankshaft toward the front of the engine to remove all end play. Move the generator shaft toward the engine to remove all end play. Use a steel rule or a 6F6922 Depth Micrometer (16) to measure dimension (X). Move the generator until dimension (X) is .34 ± 0.3" (8.6 ± 0.8) for front driven generators or .41 ± .03" (10.4 ± 0.8) for rear driven generators. NOTE: If plates (7) or (13) have no counterbore, measure dimension (X) from face (E). If plates (7) or (13) have a counterbore, measure dimension (X) from face (F).

6 Install the original shims between the generator and the support brackets (or install shims equal in thickness to the clearance between the generator and the support brackets. Install FT1010 Alignment Yoke (17), FT1011 Alignment Bar (18) and dial indicators (19) and (20) as shown for front driven or rear driven generators.

7 Use the following procedure to make sure the load on each generator support bracket is the same.

a) Loosen all vertical alignment screws. Install generator mounting bolts (21), (22), (23) and (24).

b) Tighten the bolts to one-half final torque in the sequence (21), (22), (23) and (24).

c) Rotate the crankshaft until dial indicator (19) is at location (A), and zero the indicator.

d) Loosen bolt (21) and tighten bolt (23) to one-half final torque.

e) If the indicator needle moves .002" (0.05) or less, tighten bolt (21) to one-half final torque and go to step f). If the indicator needle moves more than .002" (0.05), add shims under bolt (21) or bolt (23); loosen all bolts and repeat steps b) through e).

f) Loosen bolt (22) and tighten bolt (24) to one-half final torque.

g) If the indicator needle moves .002" (0.05) or less, tighten bolt (22) to one-half final torque and go to step h). If the indicator needle moves more than .002" (0.05), add shims under bolt (22) or bolt (24); loosen all bolts and repeat steps b) through g).

h Tighten all bolts to the final torque. The indicator needle must not move more than .002" (0.05).

8 Put the dial indicators at position (A). Move the engine crankshaft toward the front of the engine to remove all end play. Move the generator shaft toward the engine to remove end play. Zero the dial indicators. Rotate the crankshaft in the normal direction of rotation, and make a record of the readings 90° apart at (B), (C), (D) and back to (A). Before taking indicator readings at each position, make sure all end play is removed from the crankshaft and generator shaft.

9 After all readings have been taken, see ANALYSIS OF MEASUREMENTS on page 14 and REALIGNMENT OF AN ASSEMBLED UNIT on page 16.

Alignment Check of an Assembled Unit

1 Use the following procedure and make a record of all measurements and indicator readings. Do not make corrections for misalignment until after all measurements are made; see ANALYSIS OF MEASUREMENTS on page 14.

2 Move the crankshaft toward the front of the engine to remove all end play. Move the generator shaft toward the engine to remove all end play. Use a steel rule or a 6F6922 Depth Micrometer (1) to measure dimension (X). Move the generator until dimension (X) is .34 ± 0.3" (8.6 ± 0.8) for front driven generators or .41 ± .03" (10.4 ± 0.8) for rear driven generators. NOTE: If plates (2) or (3) have no counterbore, measure dimension (X) from face (E). If plates (2) or (3) have a counterbore, measure dimension (X) from face (F).

3 Install FT1010 Alignment Yoke (4), FT1011 Alignment Bar (5) and dial indicators (6) and (7) as shown for front driven or rear driven generators.

4 Put the dial indicators at position (A). Move the engine crankshaft toward the front of the engine to re remove all end play. Move the generator shaft toward the engine to remove end play. Zero the dial indicators. Rotate the crankshaft in the normal direction of rotation, and make a record of the readings 90° apart at (B), (C), (D) and back to (A). Before taking indicator readings at each position, make sure all end play is removed from the crankshaft and generator shaft.

Analysis of Measurements

1 Face alignment must be as follows:

a) On new units (or units being realigned), a TIR between (A) and (C) of up to .008" (0.20) is permitted. On used units, realignment of the generator is not necessary until the TIR between (A) and (C) is more than .012" (0.30).

b) On new units (or units being realigned), a TIR between (B) and (D) up to .008" (0.20) is permitted. On used units, realignment of the generator is not necessary until the TIR between (B) and (D) is more than .012" (0.30). In both cases, the readings at (B) plus (D) must equal the reading at (C).

2 Bore alignment must be as follows:

a) On new front driven units (or front driven units being realigned), the TIR between (A) and (C) must be .018 ± .002" (0.46 ± 0.05). IMPORTANT: Because the centerline of the generator shaft must be above the centerline of the crankshaft, the indicator reading at (C) must be minus (-) when the reading at (A) is .000" (0.00) and indicator (1) is installed as shown.

b) On used front driven units, the TIR between (A) and (C) must be .018 ± .010" (0.46 ± 0.25) with a minus (-) reading at (C). If the reading is not within these specifications, realignment of the generator will be necessary.

c) On new rear driven units (or rear driven units being realigned), the TIR between (A) and (C) must be .015 ± .002" (0.38 ± 0.05). IMPORTANT: Because the centerline of the generator shaft must be above the centerline of the crankshaft, the indicator reading at (C) must be plus (+) when the reading at (A) is .000" (0.00) and indicator (2) is installed as shown.

d) On used rear driven units, the TIR between (A) and (C) must be .015 ± .010" (0.38 ± 0.25) with a plus (+) reading at (C). If the reading is not within these specifications, realignment of the generator will be necessary.

e) The TIR between (B) and (D) can be a maximum of .008" (0.20) for new units (or units being realigned) and .012" (0.30) for used units. Again, the readings at (B) plus (D) must equal the reading at (C).

3 The end clearance of the coupling, as indicated by dimension (X), must be .34 ± .03" (8.6 ± 0.8) for front driven units and .41 ± .03" (10.4 ± 0.8) for rear driven units.

4 Examples of indicator readings within specification for new units (or units being realigned) are shown below.

Realignment of an Assembled Unit

1 If any of the measurements were not within specification as shown in ANALYSIS OF MEASUREMENTS, use the following procedure to realign the generator. IMPORTANT: After a correction has been made for a specific misalignment, all measurements must be taken again to make sure of the accuracy of the final alignment.

2 If dimension (X) was not within specification, loosen generator mounting bolts (1), (2), (3) and (4).

3 To increase dimension (X), move the generator toward the engine as shown above on the left. To decrease dimension (X), move the generator away from the engine as shown above on the right. Dimension (X) must be .34 ± .03" (8.6 ± 0.8) for front driven units and .41 ± .03" (10.4 ± 0.8) for rear driven units.

4 Use the following procedure to make sure the load on each generator support bracket is the same (omit this step if the procedure has already been performed).

a) Make sure all vertical alignment screws (5) are loose. Loosen generator mounting bolts (1), (2), (3) and (4).

b) Tighten the mounting bolts to one-half final torque in the sequence (1), (2), (3) and (4).

c) Rotate the crankshaft until dial indicator (6) is at location (A), and zero the indicator.

d) Loosen bolt (1) and tighten bolt (3) to one-half final torque while observing the indicator.

e) If the indicator needle moved .002" (0.05) or less, tighten bolt (1) to one-half final torque and go to step f). If the indicator needle moved more than .002" (0.05), add shims under bolt (1) or bolt (3); loosen all bolts and repeat steps b) through e).

f) Loosen bolt (2) and tighten bolt (4) to one-half final torque while observing the indicator.

g) If the indicator needle moved .002" (0.05) or less, tighten bolt (2) to one-half final torque and go to step h). If the indicator needle moved more than .002" (0.05), add shims under bolt (2) or bolt (4); loosen all bolts and repeat steps b) through g).

h) Tighten all bolts to the final torque. The indicator needle must not move more than .002" (0.05).

5 If the face alignment measurements were not within specification, use the following procedure.

a) If the (A) to (C) TIR was more than .008" (0.20) and the reading at (C) was minus (-), loosen generator mounting bolts (1), (2), (3) and (4). Remove the same thickness of shims from under bolts (2) and (3) as necessary.

b) If the (A) to (C) TIR was more than .008" (0.20) and the reading at (C) was plus (+), loosen generator mounting bolts (1), (2), (3) and (4). Remove the same thickness of shims from under bolts (1) and (4) as necessary.

c) If the (B) to (D) TIR was more than .008" (0.20) and the reading at (B) was less than the reading at (D), loosen generator mounting bolts (1), (2), (3) and (4). Loosen horizontal alignment screw (7) while tightening screw (8) the same amount.

d) If the (B) to (D) TIR was more than .008" (0.20) and the reading at (B) was more than the reading at (D), loosen generator mounting bolts (1), (2), (3) and (4). Loosen horizontal alignment screw (8) while tightening screw (7) the same amount.

e) Tighten all generator mounting bolts to the final torque, and check the face and bore alignment again. After the face alignment is correct, make corrections for bore misalignment as necessary as shown on page 19.

6 If the bore alignment measurements were not within specification, use the following procedure.

a) On front driven units with an (A) to (C) TIR of more than .020" (0.51) with a .000" (0.00) reading at (A) and a minus (-) reading at (C), loosen generator mounting bolts (1), (2), (3) and (4). Remove an equal thickness of shims from under bolts (1), (2), (3) and (4) as necessary. NOTE: If the reading at (C) was plus (+), the generator is too low and an equal thickness of shims must be installed under bolts (1), (2), (3) and (4).

b) On front driven units with an (A) to (C) TIR of less than .016" (0.41) with a .000" (0.00) reading at (A) and a minus (-) reading at (C), loosen generator mounting bolts (1), (2), (3) and (4). Install an equal thickness of shims under bolts (1), (2), (3) and (4) as necessary. NOTE: If the reading at (C) was plus (+), the generator is too low and an equal thickness of shims must be installed under bolts (1), (2), (3) and (4).

c) On rear driven units with an (A) to (C) TIR of more than .017" (0.43) with a .000" (0.00) reading at (A) and a plus (+) reading at (C), loosen generator mounting bolts (1), (2), (3) and (4). Remove an equal thickness of shims from under bolts (1), (2), (3) and (4) as necessary. NOTE: If the reading at (C) was minus (-), the generator is too low and an equal thickness of shims must be installed under bolts (1), (2), (3) and (4).

d) On rear driven units with an (A) to (C) TIR of less than .013" (0.33) with a .000" (0.00) reading at (A) and a plus (+) reading at (C), loosen generator mounting bolts (1), (2), (3) and (4). Install an equal thickness of shims under bolts (1), (2), (3) and (4) as necessary. NOTE: If the reading at (C) was minus (-), the generator is too low and an equal thickness of shims must be installed under bolts (1), (2), (3) and (4).

e) If the (B) to (D) TIR was more than .008" (0.20) and the reading at (B) was more than the reading at (D), loosen all generator mounting bolts. Loosen horizontal alignment screws (8) and (10) while tightening screws (7) and (9) the same amount.

f) If the (B) to (D) TIR was more than .008" (0.20) and the reading at (B) was less than the reading at (D), loosen all generator mounting bolts. Loosen horizontal alignment screws (7) and (9) while tightening screws (8) and (10) the same amount.

g) With dial indicator (6) at position (A), tighten all generator mounting bolts to the final torque. The indicator needle must not move more than .002" (0.05). Check the face and bore alignment again. Check the coupling clearance, dimension (X).

h) After all corrections have been made for alignment, install the guards over the coupling.

Alignment Check Of Individual Components

The following procedure shows how to check the engine, generator and coupling components before installation of the generator. Although this procedure is not always necessary, it is recommended if a new coupling (or parts of a new coupling) is being installed or if there is any doubt as to the specifications of the original components.

Front Driven Generators

1 With inner coupling member (1) fastened to the engine, install a dial indicator with the base of the indicator on the front accessory drive housing as shown.

2 Put the tip of the indicator on the top of the inner bore surface of coupling member (1) as shown. Zero the indicator. Use a bar to pry against a floor mounted support and shaft (2) to raise the crankshaft to the top of the main bearing bore. On new engines, a TIR of .005" - .008" (0.13 - 0.20) is normal. The maximum permissible TIR is .015" (0.38) for used engines.

3 With the tip of the dial indicator on the inner bore surface of coupling member (1), zero the indicator at location (A). Mark coupling member (1) at locations (A), (B), (C) and (D), 90° apart. Turn the crankshaft in the normal direction of rotation and make a record of the indicator readings when locations (A), (B), (C) and (D) are at the top. A maximum TIR of .010" (0.25) is permitted.

4 Put the tip of the indicator on the face of the coupling member. Position the crankshaft to the rear of its end play toward the flywheel, and zero the indicator. Move the crankshaft forward as far as possible and make a record of the indicator reading. Normal crankshaft end clearance is .008" - .021" (0.20 - 0.53) TIR. Minimum end clearance is .005" (0.13) TIR. The maximum permissible end clearance is .035" (0.89) TIR.

5 With coupling plate (3) fastened to the generator hub, install the dial indicator on the generator housing with the tip of the indicator on the outside diameter of the plate as shown. Zero the dial indicator. Mark plate (3) at locations (E), (F), (G) and (H), 90° apart. With the indicator in the zero position at location (E), rotate the generator shaft and make a record of the indicator readings when locations (E), (F), (G) and (H) are at the top. A maximum TIR of .005" (0.13) is permitted.

Rear Driven Generators

1 Install the dial indicator on the flywheel housing of the engine with the tip of the indicator on the pilot bore of the flywheel as shown. Mark the flywheel at locations (A), (B), (C) and (D), 90° apart. Zero the indicator. Rotate the crankshaft in the normal direction and make a record of the indicator readings when locations (A), (B), (C) and (D) are at the top. A maximum TIR of .006" (0.15) is permitted.

2 Put the indicator tip on the face of the flywheel. Position the crankshaft to the front of its end play and zero the indicator. Move the crankshaft to the rear of its end play and make a record of the indicator reading. A maximum TIR of .035" (0.89) is permitted. Zero the indicator and rotate the crankshaft in the normal direction of rotation. Make a record of the indicator readings when the flywheel locations (A), (B), (C) and (D) are at the top. Remove all end play before taking each reading. A maximum TIR of .006" (0.15) is permitted.

3 Install outer coupling member (1) on the flywheel. With the dial indicator mounted on the flywheel housing, put the tip of the indicator on the top of coupling (1). Zero the indicator. Raise the crankshaft to the top of the main bearing bore. On new engines, a TIR of .005" - .008" (0.13 - 0.20) is normal. The maximum permissible TIR is 0.15" (0.38) for used engines.

4 With inner coupling member (2) installed on the generator hub, mark coupling (2) at locations (E), (F), (G) and (H), 90° apart. Install the dial indicator on the generator housing with the tip of the indicator on the inner bore surface of coupling (2) as shown. Zero the indicator at position (E). Rotate the generator shaft and make a record of the indicator readings when coupling locations (E), (F), (G) and (H) are at the top. A maximum TIR of .005" (0.13) is permitted.