Part 21 Report - 1995-122
ACCESSION #: 9505300156
MKW POWER SYSTEMS, Inc.
April 24, 1995
Thomas Murley
Director
Office of Nuclear Reactor Regulation
11555 Rockville Pike
Rockville, MD 20852
Reference: Report No. 10CFR21-0071
Subject: Reportable defect with Square D type KPD relay
Dear Mr. Murley:
MKW Power Systems was notified on 2/23/95 by Wisconsin Electric - Point
Beach about a contact failure of a Square D type KPD this relay used in
their diesel generator control panel. Our review of this subject is not
yet complete. We estimate a completion date of 5/8/95.
An interim report is attached which describes the condition.
Yours very truly,
MKW POWER SYSTEMS, INC.
Michael Nuding
General Manager - Quality Assurance
MN:dg
Enclosure
Post Office Box 1928 o Rocky Mount, North Carolina 27802-1928 o
Phone: (919) 977-2720 TWX: (510) 929-0725 o FAX: (919) 446-3830
MKW POWER SYSTEMS, Inc.
Report No. 10CFR21-0071I
April 24, 1995
INTERIM REPORT
10CFR21 REPORTING OF DEFECTS
AND NON-COMPLIANCE
COMPONENT: Square D Class 8501, Type KPD relay
SYSTEM: EMD Diesel Generator control systems
CONCLUSION: To be determined
PREPARED BY: DATE:
Donald D. Galeazzi
Engineering Manager
APPROVED BY: DATE:
Michael Nuding
General Manager, Quality Assurance
Post Office Box 1928 o Rocky Mount, North Carolina 27802-1928 o
Phone: (919) 977-2720 TWX: (510) 929-0725 o FAX: (919) 446-3830
REPORT NO. 10CFR21-0071I
PAGE: 1 OF 4
SUMMARY
Recent information has revealed a change in published DC contact ratings
of Square D type KPD relays . These relays are used by MKW Power Systems
in diesel generator 125 VDC control circuits.
MKW Power Systems received notification on 2/23/95 from Wisconsin
Electric - Point Beach about a contact failure of the BTR (breaker trip
relay) within the diesel generator control panel. The contact was wired
out for customer use; Wisconsin Electric utilized the relay contact to
trip their 86 lockout relay. Investigation by Wisconsin Electric
revealed that their circuit required approximately 1.3 amps @ 125 VDC.
This lead Wisconsin Electric to verify the contact ratings of the BTR
relay (Square D class 8501, type KPD-13). Square D indicated that the
KPD-13 relay did not have any DC ratings. MKW Power Systems performed
further investigation with Square D which revealed that Square D had
recently corrected their catalog to remove the DC ratings. Previous
issues of the Square D Digest provided the following contact ratings (see
Exhibit 2):
1985: 10A continuous, make/break 60 VA @ 125 VDC.
1990: 10A continuous @ 6-120 VDC.
1992: no DC contact ratings.
1994: no DC contact ratings.
According to Square D, the above changes in contact ratings were due to
catalog errors; not due to design changes of the KPD-13 relay.
MKW Power Systems informed Square D that they have been utilizing the
KPD-13 relays in 125 VDC circuits for more than twenty years with
successful results and therefore the relays have demonstrated their
capability to handle DC loads. Square D contacted their supplier and
provided the following ratings (see Exhibit 1):
10A continuous, make/break 50 VA (.4A) @ 125 VDC.
Some KPD contacts within the MKW Power Systems' control panels are wired-
out to terminals for "customer's use". These contacts are used for
applications such as: D/G circuit breaker close, D/G circuit break trip,
86 relay trip, etc.. The above contact make/break ratings are less than
the original ratings of 60 VA and therefore users should be notified of
this deviation.
COMPONENTS
Square D class 8501, type KPD relays.
KPD-13 (3 pole version)
KPD-12 (2 pole version)
REPORT NO. 10CFR21-0071I
PAGE: 2 OF 4
CUSTOMERS AFFECTED
To be determined.
DEFECT
The defect has been identified as a change in the DC make/break contact
rating of the Square D type KPD relay. Square D's most recent
publications show the relay as not having any DC contact ratings, but
they have verified with their relay supplier that the relay can
make/break 0.4 amps (50 VA) and carry 10 amps continuously @ 125 VDC.
This make/break rating is less than the originally published rating of 60
VA @ 125 VDC. MKW Power Systems has been utilizing the KPD relay in
their 125 VDC control circuitry for more than twenty (20) years. During
this time period, contact failures due to excessive current have not been
a problem. All customers (except FP&L - Turkey Point and Wisconsin
Electric - Point Beach) have at least ten (10) years of operating
experience. Because of this operating experience MKW Power Systems does
not believe that the described change in contact ratings will affect the
operability of its diesel generators in nuclear safety related service.
Circuitry for FP&L and Wisconsin Electric control panels is being
reviewed to determine if loads beyond the 50 VA contact rating exist.
CORRECTIVE ACTION
Users should review their circuitry which utilize "customer use" KPD
relay contacts and verify that the new contact ratings are not exceeded.
For Wisconsin Electric-Point Beach relays SDRX2 and BTR have been
identified as being utilized in circuitry which exceeds the 50 VA contact
rating. Wisconsin Electric has replaced these relays with ones having
adequate contact ratings.
REPORT NO. 10CFR21-0071I
PAGE: 3 OF 4
EXHIBIT 1
(1 pages)
SQUARE D TO MKW POWER SYSTEMS
KPD RELAY CONTACT RATINGS
FACSIMILE TRANSMITTAL
SQUARE D COMPANY
AUTOMATION AND CONTROL BUSINESS
HIGHWAY 64 EAST, KNIGHTDALE, NC 27545
NUMBER OF PAGES INCLUDING THIS PAGE: 1
IF YOU HAVE NOT RECEIVED ALL PAGES CALL: 919-266-8298.
DATE: March 17, 1995
TO: Michael Nuding FAX NO. 919 / 446 - 6112
MKW Power Systems
FROM: John Nussbaum - Raleigh Marketing FAX NO. 919 / 266 - 8393
SUBJECT: 8501 KPD13 Relays
DC Contact Ratings
The 8501 KPD13 relay doesn't have any UL approved DC contact
ratings. The information published in our 1990 Digest was
incorrect. The information shown in our current Digest is
correct.
Our supplier has done some in home testing and they say it will
make and break 10 amp, at 28 VDC and 0.4 amps, at 125 VDC. The
contacts will continuously carry, but not make or break, 10
amps, at 125 VDC. There is no testing available to support a
60 VA rating.
I hope this information helps you. If I can be of any further
help, please call me at (919) 266 - 8298.
Regards,
Page 1
REPORT NO. 10CFR21-0071I
PAGE: 4 OF 4
EXHIBIT 2
(4 pages)
SQUARE D CATALOG PAGES
KPD RELAY CONTACT RATINGS (1985, 1990, 1992, 1994)
Figure "GENERAL PURPOSE CONTROL RELAYS, TYPE K, CLASS 8501" omitted.
Figure "LOGIC PRODUCTS, GENERAL PURPOSE RELAYS, TYPE K -- PLUG-IN, CLASS
8501" omitted.
Figure "General Purpose Relays, Type K -- Plug-in Relay, Application
Data, Dimensions, Wiring Diagrams, Class 8501", 2 pages, omitted.
MKW POWER SYSTEMS, Inc.
301 South Church Street
Station Square, Suite 100
Rocky Mount, NC 27804
Phone: (919) 977-2720
TWX: (510) 929-0725
FAX: (919) 446-1134
TELEFAX
DATE: April 24, 1995
COMPANY: Office of Nuclear Reactor Regulation
FAX NUMBER: 301-415-1887
ATTENTION: Thomas Murley
REFERENCE: Interim Report #10CFR21-0071I
FROM: Michael Nuding
IF YOU DO NOT RECEIVE ALL PAGES LISTED, PLEASE CALL EXTENSION 253.
PAGES (INCLUDING COVER SHEET): 12
Dear Sir:
Following this cover is a copy of an interim report for the Square D type
KPD relay.
Should you have questions, please let us know.
Sincerely,
MKW POWER SYSTEMS, INC.
Michael Nuding
General Manager-Quality Assurance
*** END OF DOCUMENT ***
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