ML20217J613

Part 21 Rept Re Incomplete Defined Changes Made to Standby DG W/Emd Diesel Engines by Mfg

ML20217J613
Person / Time
Site:	Quad Cities
Issue date:	07/14/1997
From:	Galeazzi D, Nuding M External (Affiliation Not Assigned)
To:	NRC (Affiliation Not Assigned)
References
REF-PT21-97 NUDOCS 9708140366
Download: ML20217J613 (8)

Text

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j rax:91944 stb 4 aul 14 '97 16:10 P. 01 I I ENGINE SYSTEMS, INC. ,k A 1220 SOUTH WASHINGTON STREET

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ROCKY MOUNT, NC 27801 PHONE;(919) 977 2720 g7l gr/-f 2 -O FAX: (919)446 1134 TELEFAX DATE: 07/14/07 COMPANY: Office of Nuclear Reactor Regulation FAX NUMBER: 301/415 1887 ATTENTION: Vern Hodge RbFERENCE: Report #10CFR21-0076 IR FROM- Michael Nuding . Quality Manager PAGES INCLUDING COVER SHEET: 8 Dear Sir.

A copy of our report 10CFR21-0076 lR la satached which addresses a potential defect with EMD air start motors. This is an interim report which will be finalized after we complete our investigation into this inatter.

Should you have any questions, please let us know.

Yours very truly, ENGINE SYSTEMS, INC.

ff. nn' 4e Michael Nuding g{

Ouality Manager kkl!$,$,$

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Fax 19194461134 Jul f.4 '97 16211 P 02 e

Report No.10CFR210076 IR JULY,14,1997 10CFR21 REPORTING OF DEFECTS AND NON-COMPLIANCE INTERIM REPORT r

COMPONENT: EMD Air Stari Motors #40047506 & #40047507 SYSTEM: Standby diesel generators with EMD diewi engines CONCLUSION: To be deterrnined PREPARED BY: hM' = H . DATE: 7////f7 Donal#D. Galeaz:r.i Engineering Manager REVIEWED BY. /Af%./M4, . DATE: A4 /r/pp/-

Michae Nuding / / /

Quality Asrurance Manager

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Fac9194461134 Jul 14 '97 16:12 P.03 ,

'" REPOR1 NO.10CFR21-0076 lR PAGE: 1 OF 4 s

gyMMARY:

Engine Systems, Inc. (ESI) received notification on 5/14/97 from Commonw Quad Cities nuclear plant about an increase in starter pinion abutments after ins

'new' style air motors. ESI began an investigation of this issue through coordin EMD and in0ersoll Rand (I R), the starter manufacturer. This is an interim repo report will be issued after EMD completes its investigation into ths matter. W this issue completed by mld August.1097.

Design changes were initiaten by l R to the air motors which resulted in part num by EMD. The 'new" style (#40047508 & #40047507) air motors were issued by EM replacements for the "old" style air motors (#8367694 & #8377435 respectively). #

& #8367894 are for use on left hand (standard) rotation engines (counter-clockwise while looking at engine flywheel) and are applicable for most EMD diesel generators. Right rotation engines use #40047507 & #8377435 and are only applicable for tandem diesel generator sets. Left hand rotation and right hand rotation air start motors are ident design except some components are reversed or are manufactured as mirror images t enable opposite rotation.

The EMD design pipes the two air motor pinion lines in series before going to the main air valve " activate" input. The intent of this design is to achieve mesh between the pinion gear and the engine ring gear nefore starting air is supplied to the motor to begin engine rotation (see Exhibit 1). After performin0 our own testing on an old style air motor and discussing ai motor operation with Ingersoll Rand, it appears this has not actually been occurring The old style starter (EMD 8367694) received pinion engagement air and ' ported" (sent air signal out to engage the pinion of the adjoining air motor or to activate the main air valve) after the pinion moved less than 1/8". Under most starting scenerlos, the pinion Dear will properly mesh with the engine ring gear as an activate signal is issued to the main air valve; the engine begins to crank and starts as normal. The pinion gear has chamfered teeth which allows the two gears to mesh easily; therefore, gear abutment is rare. On the rare occasion abutment occurs, the gears " fall into" mesh as the air motor begins to rotate. The following sequence occurs:

1. Gears abut. Distance from end of pinion gear to engine ring gear is 3/16' For abutment to occur, pinion gear therefore moved 3/16'. Engagement air ' ports" after pinion gear movement less than 1/8'; therefore, an activato signal is sent to the main air valve. .

2. Main air valve receives activate signal from air starter pinion line. The main air valve uses a 2 stage principle which allows a small amount of air to flow through the valve before the valve fully opens to deliver the main charge of air to the starting motors. This provides a smooth deliverance of air to the air motors and eliminates a

' shock' of air. This also enables the air motors to rotate slowly for a vnry brief period of time before the main charge air is delive,ed to the air motors; thus, the pinion gear rotates slowly and meshes with the engine ring gear before full starting torque is applied by the motor. ,

l

Fax:9194461134 M 14 '97 16:13 P,04 REPORT NO.10CFR210076 IR PAGE: 2OF4 The new style starter (EMD 40047506) received pinion engagement air and

• ported" after the l pinion moved at least 1/4". With an initial 3/16' gap between the end of the pinion gear and the edge of the engine ring gear, an activate signal would not be sent to the main air valve during pinion abutment and therefore the engine would fall to start.

COMPONENT:

l R #150BMPD88R543335 For left hand (standard) rotation engine.

EMD #40047506 l R #150BMPD88L543336 For right hand (reverse) rotation engine.

EMD #40047507 CUSTOMERS AFFECTE2 Commonwealth Edison, Quad Cities is the only ESI customer to report this type of problem.

According to Quad Citian, Savannah River also experienced increased pinion cbutment after installing the "new" style air motor (motors not supplied by ESl). Thess two installations are somewhat unique because they do not have redundant banks of air start motors and they do not have pinion recycle circuitry. This is unusual for en EMD nuclear safety related diesel generator Units with redundant banks of starting motors and recycle circuitry are not affec by this notification because these features virtually eliminate a start failure caused by pinion abutment Tandem diesel generators have an even smaller chance of start failure from pinion abutment because the quantity of air starting banks is doubled by having the second engine.

New York Power and TVA have reported that they have not experienced any change in starting reliability since installing the "new' style air start motors. Note that the EDG's at both of thesa sites have redundant banks of air start motors with pinion recycle circuitry.

• NEW" STYL.E AIR START MOTOR SALES Part Number Cust P.O. Qty Ship date Customer 40047506 47C520 2 2/27/97 Commonwealth Ed 40047506 400446 2 3/31/97 40047506 43D261 2 6/02/97 E G & G Rocky Flats 40047506 RS 358781GS2 2 7/25/94 Entergy River Bend 40047506 95-4 80628 8 12/05/95 40047506 PK0004104 KQ 1 10/24/04 Knolls Atomic 40047506 OH952K204300 1 4/03/96 Korea Electnc Power NYPA Fitzpatrick 40047506 S 94 66292 2 2/28/95 40047506 P91NJB451658001/1052012 4 3/01/95 TVA Watts Bar 40047507 P92NJB451658001/1142601 1 3/10/97

Fad 9194461134 1ul 14 '97 16:14 P.C6 l ,

4 REPORT NO.10CFR21-0076 IR PAGE, 3 OF 4 DEFECT:

Changes to the air starting motor were made by the manufacturcr which were not co dnfined and therefore were not passed along to the user. Some of these changes may the operation of the angine starting system such that a start motor pinion gear to engi gear abutment results in a start failure. This condition is only applicable to units w utilizo redundant air start motor banks and which do not have pinion recycle circuitry. The design changes aro:

"Old" stvie "Now" style . Reason Comoonent o ring improved sealing pinion piston saal metal ring

a. seal @ 0 *?S" a. unknown pinion piston a. seal @ 0.380*

from press face, from prew face,

b. 0.242' groove b. piston seal change b 0.1" groove a. standardize parts drive housing a. 4.4375" long a. 4.00* long b.1/4" npt ports b, to accommodate o.rtng 11 1/4* npi ports 5.nal on piston thru to piston neck to 1/8' dia.

CORRECTIVE ACll0N:

Corrective action has not yet been determined. The *new" style air motors appear to meet the original design intent of the EMD starting system; although, it is not clear why the "old'stylo air motors " ported" air with less than 3/16' pinion travel. Two (2) possible corrective actions arn-

1. Preferred action Add a redundant bank of air start motors to the left bank of the engine. In addition, modify the control circuitry to incorporate pinion abutment recyclo circuitry. These features are standard on all EMD safety related diesel generators fabricated by Engino Systems and were standard for most units fabricated by EMD for nuclear applications

2. Alternate.agtjoa To make the new style air motors perform the same as the old sty!o motors, the distance from the end of the pinion gear to the engino ring gear must be increased.

Adding a shim between the air motor mounting face and the engino starter mounting bracket will accomplish this. The shim thickness should be approximately 1/8" thick and can be fabricated from carbon steel. This thickness will enable the pinion air to

" port" on gear abutment and still provido adequate pinion gear engagement with the en0i ne ring

Dear. Note:

This action is not preferred because adding the shim defeats the original EMD design intent to achieve pinion engagemont of both air motors before applying main starting air to the motors.

Fax:9194461134 Jul'14 '97 16:15 P.06

, ,, , i ,

.- REPORT NO,10CFR210076-IR PAGE: 4OF4 EXHlBIT1 EMD AIR START SYSTEM DESCRIPTION (2 PAGES)

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Fax:9194461134 Jul 14 '97 16:16 P.07 t

o r .

SECTION I

4 iiinno* owe STATIONARY POWER i

AIR STARTING SYSTEM The basic engine starting system utilizes air motors GENERAL with pinion drive to flyw heel ring gear. Operational A single air starting motor, Fig. 41, is used on 8 control is the same for either single or dual air cyhnder engines, while 12,16, and 20-cylinder starting motor starting system. An ENGINE i

engines use dual air atarting motors, Fig. 4 2. An START pushbutton is located on the engine control l

installation can also be equipped with single or dual cabinet. The pushbutton is a single contact switch i

electric motors, which remains closed during the engine cranking j period.

E The starting system control of turbocharged engines

~

la interlocked to require the turbocharger lube oil g (soak back) circulating pump to be running, and the n

Starting Mo governor SPEED CONTROL to be set for idle i

speed before the engine may be started.

Refer to Fig. 4 3 and the following paragraphs for

., 6

! S c s @K %q' operation of a basic dual air starting motor starting i

• • system.

I am

' shutore vai DESCRIPTION

y a. ,

- Upon receiving a start signal, the solenoid valve is l

l 4

!Q ~Nk., Strainer energized to allow air from the tanks to pass d4 Air Line through the solenoid valve to the pinion gear end of j ~

, Air Start Valva the lower starting motor. The entry of air moves the

? Y 1 Lubricator pinion gear forward to engage with the engine ring j -4 --

• gear, Movement of the pinion gear uncovers a port 811 Wing air pressure to be released to the upper

! Fla.41 - Single Motor Air Starting Systern starting motor which, m turn, engages its pmion gear with the engine ring gear. Both pinion gears l being engaged, the air released from the uncovered i

port in the upper motor. The released air opens the air relay valve, which in turn opens the air starting valve, and releases the main staning air supply, j

Starting air passes through the air line fubricator, j

releasing an oil air mist into the starting motors, automatically lubricating the motors. The muhi-i

' vane motors drive the pinion gears, rotating the ring gear, cranking the engine.

j I

The system is designed so that unless both pinion l gears are engaged no attempt can be made to start j

the engine with one motor. There is also a shutoff valve in the system which is manually operated.

,o When maintenance is being performed, the shutoff 4

' valve is closed to prevent inadvertent cranking of Fig.4 2 - Dual Motor Air Starting System the engine.

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Fax:9194461134 bul14'97 16:17 P.03

. Secti:n 4

,i g, Control n e Voltage p

2. *g l Lube Oil

" Engine ay . Pressure L- - Switch Start" Solenoid Air Valve Flywheel  :

Ring Geer

--o-- }

3 _

Alf E Air Line Relay Pinion 1 = per i ubricetor

- Valve Retracted t- t g 7 - ..otor '

..- c- - / Streiner Air Pmion r Wr 3 #-- "/

W<>

g " Supply Engaged t Motor O

& w ~ A * - - 2 LI Pinion Engaging Line Check Velve

/Solennid Valve With Air Dump Vent ,

Fig.4 3 -Typical Air Storting System Diagram If oil does not tinw. removeiop plug and drip gland.

MAINTENANCE Clean parts and passages, using kerosene, and blow The air starting sytem requirca very little mainte- out with compressed air.

nance other than c! caning and lubrication.

Replace any defective gaskets or packing. Reassem-The air line lubricator is the only component of the hte, tightening drip gland firmly, but carefully, system which requires maintenance at intervals specified in the Scheduled Maintenance Program.

Compounded oils containing graphites, soap, or fillers should not be used in the lubricator, Oil level in the bowl should be checked and the needle valves should be adjusted for an oil flow ate of three drops per minute. This can be checked Refer to applicable Engine Maintenance Manual for maintenance data on starting motors and visually through the sight glass in the front of the unattached accessories lubricator.

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