Product Support Program For Addressing Generator Shaft Current On Certain 3508, 3508b, 3512, 3512B, 3516 And G3516 And SR4B Engine Generator Sets Caterpillar

NOTE: This Program can be administered either before or after a failure. In either case the decision whether to apply the Program is made by the dealer. When reporting the repair, use "PS4076" as the Part Number and "7755" as the Group Number. If administered before failure, use "56" as the Warranty Claim Description Code and use "T" as the SIMS Description Code. If administered after failure, use "96" as the Warranty Claim Description Code and use "Z" as the SIMS Description Code.

NOTE: This Revised Service Letter replaces the July 16, 1997 (Revised June 1998) Service Letter. Changes have been made to the TERMINATION DATE.

Termination Date

Problem

Some 3508, 3508B, 3512, 3512B, 3516 and G3516 and SR4B Engine Generator Sets with 690, 691, 692, 693, 695, and 696 Frame Generators may experience an induced shaft current of 2 to 5 amps in the generator shaft. This current will flow through the generator bearing and the engine main bearings. The flow of this current may cause failures of the bearings.

Affected Product
Model & Identification Number

3508 (23Z5937, 23Z5939, 23Z5965, 23Z5973, 23Z5994, 23Z5998-6000, 23Z6002-6008, 23Z6011, 23Z6012, 23Z6014, 23Z6016, 23Z6019, 23Z6021, 23Z6024, 23Z6032, 23Z6036, 23Z6039, 23Z6049, 23Z6050, 23Z6059, 23Z6064, 23Z6066, 23Z6068, 23Z6070, 23Z6073, 23Z6074, 23Z6078, 23Z6080, 23Z6084-6086, 23Z6088, 23Z6095, 23Z6096, 23Z6101, 23Z6107, 23Z6114, 23Z6116, 23Z6128, 23Z6129, 23Z6133, 23Z613423Z6139, 23Z6143, 23Z6147, 23Z6150, 23Z6153, 23Z6155-6157, 23Z6162, 23Z6165, 23Z6168, 23Z6172, 23Z6180, 23Z6188, 23Z6189, 23Z6193, 23Z6194, 23Z6202, 23Z6203, 23Z6208-6213, 23Z6215, 23Z6219-6221, 23Z6223, 23Z6227-6231, 23Z6234, 23Z6236, 23Z6240, 23Z6242, 23Z6250, 23Z6258, 23Z6264, 23Z6268 , 23Z6270, 23Z6271, 23Z6276-6279, 23Z6287, 23Z6294, 23Z6295, 23Z6297, 23Z6300, 23Z6302, 23Z6306, 23Z6308, 23Z6309, 23Z6313-6315, 23Z6319, 23Z6320, 23Z6327, 23Z6334, 23Z6336, 23Z6338, 23Z6342, 23Z6344, 23Z6346, 23Z6353, 23Z6356, 23Z6361, 23Z6363, 23Z6366, 23Z6369, 23Z6370, 23Z6371, 23Z6373, 23Z6376, 23Z6378, 23Z6379, 23Z6391-6393, 23Z6403, 23Z6405-6407, 23Z6410, 23Z6414, 23Z6416, 23Z6417, 23Z6422, 23Z6423, 23Z6426, 23Z6427, 23Z6432, 23Z6433, 23Z6439, 23Z6440, 23Z6442, 23Z6444, 23Z6447, 23Z6450-6452, 23Z6464-6468 , 23Z6472, 23Z6474, 23Z6475, 23Z6483-6488, 23Z6494, 23Z6499, 23Z6500, 23Z6502, 23Z6504, 23Z6507, 23Z6508, 23Z6511, 23Z6512, 23Z6518, 23Z6520, 23Z6522, 23Z6529-6531, 23Z6533, 23Z6535-6539, 23Z6541, 23Z6568, 23Z6569, 23Z6575-6577, 23Z6582, 23Z6583, 23Z6589, 23Z6590, 23Z6593, 23Z6594, 23Z6596, 23Z6597, 23Z6599, 23Z6603, 23Z6610, 23Z6613, 23Z6614, 23Z6620, 23Z6621, 23Z6631, 23Z6632, 23Z6635-6637, 23Z6661, 23Z6662, 23Z6664-6667, 23Z6673, 23Z6675, 23Z6678, 23Z6681-6683, 23Z6687, 23Z6689, 23Z6690, 23Z6692, 23Z6693, 23Z6696, 23Z6698-6700, 23Z6705, 23Z6717, 23Z6719-6723, 23Z6727, 23Z6728, 23Z6735, 23Z6737, 23Z6739, 23Z6741, 23Z6742, 23Z6744, 23Z6748-6750, 23Z6754, 23Z6756, 23Z6757, 23Z6759, 23Z6760, 23Z6763, 23Z6765, 23Z6767, 23Z6774-6777, 23Z6782, 23Z6787, 23Z6796, 23Z6799-6801, 23Z6803-6806, 23Z6809, 23Z6813, 23Z6814, )

3508B (4GM129-155, 4GM159-201, 4GM203-210)

3512B (8RM112, 8RM118, 8RM119, 8RM121, 8RM138, 8RM141, 8RM142, 8RM144-146, 8RM148, 8RM169, 8RM170, 8RM176-183, 8RM185, 8RM186, 8RM189, 8RM190 6WN84-86 , 6WN88, 6WN90-95, 6WN99-102, 6WN1056WN109-112, 6WN116, 6WN117, 6WN120 , 6WN124, 6WN126)

3512 (24Z6282, 24Z6311, 24Z6315-6317, 24Z6323, 24Z6327, 24Z6330, 24Z6333, 24Z6337, 24Z6338, 24Z6341, 24Z6343-6346, 24Z6348, 24Z6350-6357, 24Z6369, 24Z6372-6376 , 24Z6381, 24Z6384, 24Z6391, 24Z6396, 24Z6397, 24Z6399-6407, 24Z6409-6411, 24Z6413-6415, 24Z6418-6420, 24Z6423, 24Z6424, 24Z6427, 24Z6430, 24Z6433, 24Z6435, 24Z6436, 24Z6438, 24Z6440-6443, 24Z6445-6455, 24Z6459, 24Z6460, 24Z6462, 24Z6463, 24Z6465, 24Z6467, 24Z6468, 24Z6470-6474, 24Z6480, 24Z6481, 24Z6487, 24Z6488, 24Z6490-6493, 24Z6495, 24Z6501, 24Z6502, 24Z6507-6510, 24Z6512-6515, 24Z6517-6522, 24Z6525, 24Z6527, 24Z6530, 24Z6531, 24Z6534, 24Z6535, 24Z6538, 24Z6540, 24Z6542-6546, 24Z6550, 24Z6551, 24Z6556, 24Z6559-6561, 24Z6563, 24Z6564, 24Z6566-6569, 24Z6571-6574, 24Z6576-6578, 24Z6580, 24Z6582-6589, 24Z6591, 24Z6593, 24Z6594, 24Z6596-6602 , 24Z6604-6617, 24Z6619, 24Z6621, 24Z6622, 24Z6624, 24Z6626-6632 , 24Z6634, 24Z6636-6638, 24Z6641-6648, 24Z6650-6656, 24Z6659, 24Z6660, 24Z6663, 24Z6665, 24Z6666, 24Z6668, 24Z6670-6676, 24Z6678, 24Z6679, 24Z6682-6686, 24Z6688-6695, 24Z6697, 24Z6698, 24Z6701, 24Z6702, 24Z6706-6713, 24Z6715-6721, 24Z6723, 24Z6724, 24Z6726-6732, 24Z6734-6736 , 24Z6741, 24Z6743-6746, 24Z6749, 24Z6751, 24Z6752, 24Z6754, 24Z6756, 24Z6758-6761, 24Z6763-6766, 24Z6768-6770, 24Z6772-6774, 24Z6777, 24Z6779, 24Z6781-6783, 24Z6785-6787, 24Z6790, 24Z6795, 24Z6797-6799 , 24Z6801-6806, 24Z6809-6812, 24Z6815-6818, 24Z6822-6841 , 24Z6844-6857, 24Z6859, 24Z6861, 24Z6863-6869, 24Z6871-6873 , 24Z6875-6887, 24Z6890-6893, 24Z6896-6902, 24Z6905-6909 , 24Z6911, 24Z6916-6919, 24Z6921-6932, 24Z6934-6939, 24Z6941, 24Z6942, 24Z6946, 24Z6947, 24Z6949-6952, 24Z6954, 24Z6956-6963, 24Z6968-6981, 24Z6984, 24Z6985, 24Z6988-6990, 24Z6996, 24Z6999, 24Z7003, 24Z7007, 24Z7009, 24Z7017, 24Z7019-7021, 24Z7024, 24Z7026-7029, 24Z7031-7044 , 24Z7046-7054, 24Z7056-7066, 24Z7068, 24Z7069, 24Z7071, 24Z7072, 24Z7074-7084, 24Z7087-7089, 24Z7091, 24Z7092, 24Z7094, 24Z7097, 24Z7100-7102, 24Z7104, 24Z7108, 24Z7109, 24Z7111-7118, 24Z7120, 24Z7123-7128 , 24Z7130, 24Z7131, 24Z7135-7154, 24Z7157-7162, 24Z7164, 24Z7169, 24Z7171-7177, 24Z7179, 24Z7183-7187, 24Z7193, 24Z7195, 24Z7196, 24Z7200-7202, 24Z7204, 24Z7205, 24Z7208, 24Z7210-7212, 24Z7214-7216, 24Z7221, 24Z7224, 24Z7225, 24Z7229, 24Z7230, 24Z7233, 24Z7235-7238, 24Z7240, 24Z7244, 24Z7245, 24Z7247-7252, 24Z7254, 24Z7256-7258, 24Z7260-7266, 24Z7271, 24Z7273, 24Z7274, 24Z7276-7285, 24Z7287-7289, 24Z7291-7293, 24Z7297-7305, 24Z7307-7309, 24Z7311-7314, 24Z7316, 24Z7317, 24Z7320, 24Z7322-7324, 24Z7328, 24Z7329, 24Z7338, 24Z7340, 24Z7342, 24Z7344, 24Z7345, 24Z7347, 24Z7350, 24Z7353, 24Z7360, 24Z7362, 24Z7364, 24Z7366, 24Z7368-7370, 24Z7372-7374, 24Z7376, 24Z7379, 24Z7380, 24Z7382-7384, 24Z7387-7394, 24Z7396, 24Z7398-7417, 24Z7420, 24Z7421, 24Z7424-7426, 24Z7428-7431, 24Z7435-7445, 24Z7447-7454, 24Z7456-7463, 24Z7465, 24Z7467, 24Z7468, 24Z7470-7474, 24Z7476, 24Z7479, 24Z7486, 24Z7490-7492, 24Z7494-7497, 24Z7499, 24Z7501-7503, 24Z7507, 24Z7509, 24Z7511, 24Z7512, 24Z7514-7530, 24Z7532-7540, 24Z7542-7546, 24Z7548-7551, 24Z7555, 24Z7558-7560, 24Z7568, 24Z7570, 24Z7573, 24Z7575-7580, 24Z7582-7588, 24Z7590, 24Z7592-7604 , 24Z7606, 24Z7607, 24Z7609-7642, 24Z7644-7656, 24Z7659-7676 , 24Z7679-7681, 24Z7683-7700, 24Z7702, 24Z7704, 24Z7706-7708 , 24Z7711, 24Z7717-7731, 24Z7733-7738, 24Z7742, 24Z7746, 24Z7748-7756, 24Z7758-7760, 24Z7762, 24Z7763, 24Z7765-7771, 24Z7775, 24Z7776, 24Z7778, 24Z7785, 24Z7786, 24Z7788, 24Z7789, 24Z7792, 24Z7796-7801, 24Z7807, 24Z7809, 24Z7811, 24Z7813, 24Z7814, 24Z7819-7824, 24Z7826, 24Z7827, 24Z7829-7833, 24Z7837, 24Z7840)

3516 (25Z4382, 25Z4385, 25Z4430, 25Z4435, 25Z4450, 25Z4509, 25Z4510, 25Z4515, 25Z4545, 25Z4546, 25Z4559, 25Z4561, 25Z4562, 25Z4566, 25Z4609, 25Z4624, 25Z4629, 25Z4677, 25Z4678, 25Z4688, 25Z4696, 25Z4697, 25Z4725, 25Z4733, 25Z4737, 25Z4740, 25Z4796, 25Z4878, 25Z4891, 25Z4922, 25Z4930, 25Z4936, 25Z4950, 25Z4990-4992, 25Z5012, 25Z5015, 25Z5052, 25Z5057, 25Z5059, 25Z5125, 25Z5130, 25Z5152, 25Z5153, 25Z5155, 25Z5156, 25Z5234, 25Z5237, 25Z5288, 25Z5320, 25Z5343, 25Z5368, 25Z5372, 25Z5373, 25Z5395, 25Z5400, 25Z5415, 25Z5462-5464)

G3516 (4EK494, 4EK671, 4EK672, 4EK816, 4EK1021)

SR4B (3EN501)

Generator

Parts Needed

1 - 1474529 Shaft Current Test Kit

NOTE: The 1474529 Shaft Current Test Kit can be used to test multiple generators. Only one per dealer is required.

Action Required

See the attached procedure.

Service Claim Allowances

Parts Disposition

If the test procedure shows the generator to have shaft current greater than 500 milliamperes (0.5 Amp), contact Caterpillar 3500 Diesel Engine Customer Service, at (765) 448-5911 for further instructions.

Attach.

(1-Test Procedure)

Test Procedure

On single bearing generators the generator shaft leakage current will flow through the generator shaft and flex plate to the flywheel, crankshaft, main bearings, block and generator frame. Then completing the circuit through the generator bearing to the rotor. The current flowing through the bearings will produce an arcing discharge through the oil film. On the engine main bearings this discharge may look like a star burst pattern, and on the generator bearing it will look like a bar code pattern. Reference SEBDO531 and SEBDO610 for further descriptions and pictures. The discharge (if present) will result in bearing failures after low operating hours (less than 500 hours). All 690 Frame Generators manufactured after February 17,1997 are being production tested for shaft currents.

It is suggested that Priority be given to testing generator sets in critical applications where an engine or generator bearing failure will cause a major power interruption.

Service Tools Needed

1 - 8T0900 Clamp-on Ammeter

1 - 9U7730 (Fluke 87), or 6V3030 (Beckman 3010), or 6V7070

Beckman HD110) Digital Multimeter

1. Shut down the generator set.

2. Lockout the engine from starting and disconnect the battery negative to the starting motor.

3. Remove an unused starter motor cover on the flywheel housing and attach the flywheel pickup test fixture provided in the 1474529 Test Kit using the bolts removed with the cover.

4. Push the handle of the flywheel pickup test fixture toward the engine flywheel to verify there is contact on the ring gear in the area without teeth.

5. Remove the rear or side cover(s) of the generator terminal box.

6. Remove the generator bearing top grease fitting and install a copper plug fitting provided in the test kit.

7. Connect the included wire from the flywheel pickup test fixture to the bearing bracket copper plug fitting. Be sure the wire will not contact any rotating parts in the generator.

8. Clamp the 8T0900 Clamp-on Ammeter around the wire.

NOTE: The 8T0900 Clamp-on Ammeter readings below 500 milliamps are not accurate. Thus, the 8T0900 is to be used as an indicator of shaft current above 500 milliamps (0.5 Amp).

9. Connect the Clamp-on Ammeter to the Digital Multimeter V and COM terminals. Polarity is not important. Set the multimeter to measure 200 millivolts AC. The millivolt reading will be equal to the milliamps being measured. (Reference SEHS8420, using the 8T0900 AC/DC Clamp-on Ammeter)

10. Determine that the handle on the flywheel test fixture is pulled away from the flywheel (No contact is being made with the flywheel).

11. Connect the battery cables and start the engine.

12. Allow the engine to warm up, and apply at least 60 % of rated load. (Use a load bank if necessary)

13. For a reference measurement, push the handle of the pickup test fixture toward the engine flywheel until a firm contact is made on the flywheel ring gear, and not on the ring gear teeth.

14. Observe and record the reading on the multimeter. This reading should be greater than 1 milliamp, or different than the reading when the clamp-on ammeter is not clamped onto the wire. The resolution of the multimeter reading is no greater than 100 milliamps. If no reading is shown, check the wiring, the contact on the generator copper plug fitting, and the contact to the flywheel ring gear.

NOTE: As soon as contact is made with the rotating flywheel ring gear there may be a small surge reading. The best continuous reading is to be recorded.

15. After obtaining a reading, pull the handle of the test fixture away from the flywheel.

16. After the generator has operated under load for approximately 2 minutes, push the handle of the test fixture toward the engine flywheel until a firm contact is made on the flywheel ring gear.

17. Observe and record the reading on the multimeter. Then pull the handle of the test fixture away from the flywheel.

18. Repeat step 16 and 17 after the generator has ran under load for approximately 5 minutes, for approximately 10 minutes, and for approximately 15 minutes.

19. Remove the load, allow the engine to cool down, and shutdown the engine.

20. Remove the test fixture, the connecting wire, and the generator grease fitting copper plug. Install the generator grease fitting, covers and the starter motor cover.

Make a record of the measured milliamp readings, the engine serial number, the generator serial number, the engine operating hours, and the date.

If the readings are less then 500 milliamps there is no problem with generator shaft currents.

If the readings are greater than 500 milliamperes (0.5 Amp), there should be evidence of the electrical discharge on the engine and generator bearings. To confirm this damage on 3500 Series Engines, remove #6 engine main bearing cap and inspect the bearing and journal surface for the typical electrical discharge patterns.

After the main bearing has been inspected, contact Caterpillar 3500 Diesel Engine Customer Service, at (765)448-5911 for further instructions.