ML021830510
| ML021830510 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse, Oconee, Braidwood  |
| Issue date: | 06/07/2002 |
| From: | Thigpen J Rockwell Automation |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML021830510 (5) | |
Text
Rockwell Automation/PowerSystems Quality Assurance Department P.O. Box 250 Flowery Branch, GA 30542 Phone: 770.967.3381 Fax:
770.965.5295 Rockwell Automation June 7, 2002 To:
Document Control Desk United States Nuclear Regulatory Commission Washington, DC 20555
Dear Sir or Madam:
In accordance with Title 10, Code of Federal Regulations, Part 21, Rockwell Automation/Power Systems is making formal notification as required by 10CFR21.21 for event #38909.
A.
Name and address of the individual informing the NRC.
James Thigpen Quality Assurance Manager Rockwell Automation/Gainesville Motor Plant 4349 Avery Drive Flowery Branch, Georgia B.
Identification of Basic Component being Supplied.
AC Motor C.
Name of firm supplying basic component.
Rockwell Automation/Gainesville Motor Plant 4349 Avery Drive Flowery Branch, Georgia D. Nature of the defect, deviation, or failure to comply.
Subject:
Nuclear Nonconformance Event Number 38909 This notice was issued because of a motor failure experienced by Duke Power Company at the end of March in 2002.
The sales order number for the motor that failed was 1KXV60125.
The motor was examined by Reliance Electric and Duke Power personnel at the Westinghouse Service Center to in AIfen-Baley Qk.
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determine the cause of failure. The cause of failure was the winding grounded to the frame. Based on the fact that the coil could be moved in the slot with hand pressure, it was concluded that the root cause of the failure was the coil moved inside the slot due to inadequate slot fill.
This motor was a two-speed motor and failed when switching from low speed to high speed. The investigation concluded that a current surge caused during the speed change when voltage was re-applied resulted in the coil moving inside the slot.
Engineering focused on determining the reason for the low slot fill.
The slot detail used on this motor is known as "a "depressed slot" configuration. This means that there is "a "wedge" notch in the slot recessed a certain distance below the top of the slot. The distance from the top of the slot to the wedge notch is dependent on the particular slot detail. The proper way to use this type of slot is to confine the wire beneath the wedge notch leaving the top portion of the slot open.
It is believed that the motors built at the Gainesville facility were wound without using the wedge notch. This would not be a problem if filler material were added in the slot to take up space. We believe that filler material was only added to motors built on sales order #1KXV60247.
Therefore, it is believed that the slot fill in the other motors built using this slot configuration at the Gainesville facility may be inadequate and coil movement inside the slot is possible.
A search of the corporate engineering database revealed each slot detail that uses this configuration. Once the particular slot details were identified, the engineering database at the Gainesville facility was searched to determine if any of these slots had been used. The results of the search identified four electrical designs that utilized a depressed slot. By using these electrical designs we determined specific sales orders that were built since the Nuclear product was transferred to Gainesville. The sales orders are 1KXV60028, lKXV60084, 1KXV60125, 1KXV60133, 1KXV60228 and IKXV60247.
The customer(s) that purchased these motors has been notified of the potential problem. Rockwell Automation will work with the customer to determine the best feasible solution.
STEPS TAKEN TO PREVENT FUTURE OCCURRENCES ROCKW1LL8 SOFTWARE
The depressed slot configuration was new to the Gainesville facility when the Nuclear product was transferred. Neither engineering personnel nor manufacturing personnel had ever seen this type of slot.
Therefore, recognition of possible problems and proper winding techniques were not available. Since that time, engineering personnel have been taught the origination of the slot and typical uses. Engineering personnel have also been trained to recognize the slot and how to determine if the wedge notch is supposed to be used. We have learned that even if the slot has the wedge notch it is not always supposed to be used. A list of the stator slots with the expected use of the wedge notch has been obtained and distributed to engineering personnel. This list was used to assist with the training process and will not be a controlled document.
A portion of the training included how to recognize if the wedge notch is supposed to be used which eliminates the need for the list used in training.
There are insulation bills of material that dictate the insulation to be used for a particular motor. A major factor that determines the proper size for the insulation pieces is the slot detail. The insulation bills of material for the depressed slot stators where the wedge notch is supposed to be used have been changed where the insulation cannot be used if the wedge notch is not employed.
The insulation pieces have been sized specifically for using the wedge notch. Also, a check sheet has been instituted during the design process per RSP 541&2-13. This is a controlled document and is part of the electrical design review. This check sheet will be added to the electrical design folder and specifically checks for slot fill and slot detail configuration.
Finally, the plant personnel have been trained to recognize the depressed slot configuration and how to wind the stator properly utilizing the wedge notch.
CONCLUSION The potential problem of inadequate slot fill is confined to motors built at the Gainesville facility using the depressed slot configuration. Other Rockwell Automation facilities (RSN and RST) that utilize the depressed slot configuration were consulted and assisted with training RGG personnel. These other facilities were cognizant of the depressed slot configuration and proper winding and insulation procedures. Even though there is no guarantee SAlle-Badley~
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that the motors will fail, we also cannot guarantee that the motors will not fail. Therefore, Rockwell Automation believed that customer notification of the potential failure was justified. All motors with a potential problem have been identified by sales order number and our customer has been notified. Our customer, HowdenBuffalo, has in turn notified each end user. Every effort will be made to satisfy the end user and to accommodate their timeframe to successfully eliminate potential premature motor failure due to inadequate slot fill.
Personnel at the Gainesville facility have been trained to recognize and properly manufacture motors utilizing the depressed slot configuration.
D.
The Discovery Date.
May 9, 2001.
E.
The Quantity and Location of Motors Affected.
PART/COMPONENT NUMBER:
- 1) 1KXV60028 - HOWDEN P/N 600287-85R Qty. 1
- 2) 1KXV60084 - HOWDEN P/N 600287-52R Qty. 1
- 3) 1KXV60125 - HOWDEN P/N 600276-3R Qty. 1
- 4) 1KXV60133 - HOWDEN P/N 600276-17R Qty. 1
- 5) 1KXV60247 - HOWDEN P/N 600276-3R Qty. 2
- 6) 1KXV60228-HOWDEN P/N 600276-17R Qty. 1 1
2 3
4 5
6 7
HowdenBuffalo NL7744 NL9794 NM1877 NM2193 2827 2827 1898 PO #
End User/Sold to:
Spain CornEd Duke First Energy, Duke Duke First Energy, Toledo Edison Toledo Edison Station Vandellos Braidwood Oconee Davis Besse Oconee Oconee Davis Besse NPX #
NPX68917 NPX68203 NPX58761 NPX62423 NPX58761 NPX58761 NPX62423 Fan SIN GF21943 GF21631-46 GF13705 GF16182 GF13705 GF13705 GF16182 Sales Order #
NPN31928 NPN32790 NPN33586 NPN33748 560085 560085 560055 Motor P/N 600287-85R 600287-52R 600276-3R 600276-17R 600276-3R 600276-3R 600276-17R Motor S/N 1 KXV60028 1 KXV60084 1 KXV60125-1 KXV60133 1 KXV60247-1 KXV60247-1 KXV60228 Ti T1 T2 Ti Customer PO#
6032497 48H310 ON26432 S 086669 D98 ON34982 ON34982 7D13315 Shipped On:
09/11/98 02/26/99 04/30/99 04/28/99 03/30/00 03/30/00 03/21/00 Contaminated No No Contaminated Contaminated No Contaminated Status In Storage, In Storage, At Installed, At In Storage Installed, issued Return issued Return Westinghouse currently down Westinghouse currently down authorzation authorzation
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F.
The Corrective Action which has been completed.
HowdenBuffalo initiated a request for corrective action CAM523 on 5/16/2002 which was completed, accepted and verified by Todd Gunvelson QA Manager HowdenBuffalo on 5/21/02.
G.
Other Information.
Orders are in process to deliver two new motors as replacements for 1KXV60133 and 1KXV60228.
Return Authorizations are issued for 1KXV60028 and 1KXV60084 which were in storage.
Orders for new windings and frame assembly are in process to be used in with the returned motors.
Replacement motors for 1KXV60125-Tl and 1KXV60247-Tl & T2 are not requested by end user.
Sincerely, Mr. James Thigpen Quality Assurance Manager, Gainesville Motor Plant Rockwell Automation Allen Bradl~ey RLJNCEUDOtOGE 1
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