ML20207N576

Maint Procedure MP 1405.05, 480-Volt Type Ak Reactor Trip Breaker Maint & Testing

ML20207N576
Person / Time
Site:	Davis Besse
Issue date:	03/13/1982
From:	Carr P, Matheny D, Quennoz S TOLEDO EDISON CO.
To:
References
MP-1405.05, TAC-53120, NUDOCS 8701140297
Download: ML20207N576 (11)

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,. 1. PURPOSE 1.1 The purpose of this proc.edure is to provide instructions for the 3! cleaning, inspecting and testing of CE 4COI Type AK Reactor Trip breakers. This procedure should be performed on ecch breaker in accordance with the preventive aaintenance schedule, or es -

needed ' for corrective mainLanance.

1.2 Not all portions of this procedure vill be applicable to all breakers. Enter the syubol "NA" in the applicable blanks as neces sa ry. This in alco appropriate when only portions of this procedure are being conducted as may' occur during operability-testing, troubleshooting, etc.

2. REFERENCES 3lL 2.1 GEI-50299 Poser Circuit Breakers 3

2.2 GEF-4149 Renewal Parts - AX25 Frame Size 2.3 GEI-90890 AKD5 Powermaster Lou Voltage Drawout Switchgear 2.4 CE Service Advice Letter No. 175 (CFDD)'9.3, dated April 2, 1979 31 2.5 ~CE Service Advice Supplement 175-9.33, dated' June 9, 1983

', 2.6 Failure of GE Type AX-2 Circuit Breakers in Safety Related Systems, IE Bulletin No. 79-09, dated April 17, 1979 3 2.7 GE Service Advice Letter No. 175-9.20, dated April 21, 1984 2.8 Hulti-Amp Institute Circuit Breaker Haintenance Training Manual 2.9 B&W Service Dulletin 25-014, dated April 24,1985

'3. REQUIRED EQUIPMENT

.3 3.1 HP 1410.33, Hegger and Continuity Testing of Electrical Equipment 3.2 SY 5030.20, CRD Trip Dreaker Response Time Test 3.3 Spring Scale 0-5 lbs. or equivalent 31 s 3.4 GE Spec. No. D50H15 or RPM No. 5 grease or equivalent l'

l- 3.5 GE Spec. No. D50H47 lubricant or equivalent i

l 3.6 Scotch-Brite pads or equivalent i

3l 3.7 DC Pcwcr Supply capable of delivering approximately 10 amps at

125VDC 3l l

2 MP 1405.03.3 3.3 Adjustable AC Voltage Source i 3.9 Simpscn Model 150 Digital Multimeter or equivalent 3.10 Breaker Handle for manual breaker operations 3.11 Micro-ohv. meter 3.121:end paper 3.13 Carbon paper 3l 3.14 MP 1410.63, Electrical IIaintenance Guidelines

4. PRECAUTIONS AlfD LIMITATIONS 4.1 Leave latch surfaces clean and dry. Do not lubricate.

4.2 Recove amf excess grease with a clean cloth to prevent accumula-3l tion of dust and dirt. Refer to MP 1410.63 for cleaning asterials.

4.3 If the primary disconnects are to be removed and/or replaced, follou the applicable GE Instruction Manual for setting the propcr teasion.

4.4 The GE Instructica Manuals vill usually have a letter after the aanual number to indicate which revision it is (ie. CEI-50299E indicates revision five of Instruction Manual GEI-50299). This procedure vill not list the revision letters. However, the latest revisions should be used where applicabic.

4.5 Safety Tanging Procedure A9 1803.00 and TED Safety procedures vill be in effect and followed throughout this procedure.

3l 4.6 Uhen using the Simpson Ifodel 460 for ac measurements use the 200v scale. Uhen setting the test set output voltage to 200v adjust the voltage ta 199.97. Do not use the 600v scale for this measurcaent since this will decrease the test accuracy.

1:0TE: Uhen set on the 200v scale the Simpson rc.eter will not be daaaged by over-voltage of up to 600v.

4.7 The procedure does not cover every circumstance or possibility.

Uhen a problem or nonconformance is noted, the testing elec-3 trician is responsible for notifying supervision to easure that r.ll deficic>ncies are resolved before a breaker is returned returned to service. All deficicucies noted shall be listed on the Mainteuence Work Order.

4.8 Record the "As Found" and "As Lef t" parameters on Attachment 1.

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3 LMP 1405.05.3

), 5. PREREQUISITZS

.31 5.1 The Shif t Supervisor has given his permission to remove the breaker frora service. (This step is only required if the breaker aust be removed from a cell. It is UA if the breaker is not in a cell).

3l Channel No. Serial No.

. 5.2 The circuit breaker has been removed from service end has been placed in a convenient location for testing with all electrical power, both primary and control disecanected.

5.3 The test equipment to be used is in calibration.

3 Equipment No. Cal. Date Section 5 conpleted by Date

6. PROCEDURE I

'3 6.1 Prcmaintenance Testing (As Found) 6.1.1 Micro ohmmeter test - TLis test, which checks the internal resistance of the current carryiag mechanism, contacts, etc., will give a good indication of loose and/or bad connections, dirty pivot points, and dirty contacts. Measure the stab to stab resistance for each phase.

Values of 0 to 100 micro ohms are considered new conditica, while a reading of 400 to 500 micro ohms indicates that trouble is developing. If high readings are found, a discantling of the breaker is necessary to find the high resistance point.

6.1.2 Check (and adjust if necessary) the pick-up setting of the instantaneous undervoltage device. For some breakers, the standards for noninal voltage ratings cad pick-up settings have been raised since the breakers were shipped from the factory. If the voltages and pick-up settings deviate fro:a these values, the device should be re-adjusted while it is on the breaker.

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4 MP 1405.05.3 The pick-up rettings recommended in Paragraph 3 of-the 1979 Service Advice which are recom ended by ANCI C37.13-1931, . we been in existence since 1972.

3i Cince the pick-up calibration spring also supplies I the stored energy to trip the breaker on loss of voltage, setting the undervoltage device to these recomended values casures that the caximaa stored techanical energy is availabic in the undervoltage device to trip the breaker. The allowable values for the pick-up voltage are as listed.

NOMlliAL PICK-UP TOLEIUNCE NOMINAL VOLT!.GE PICK-UP SETTING ALLONELE VALUSS 120V AC 102V AC 100-106V AC NOTE: To ensure the raximua stored energy is available, maintain pick-up voltage at upper end of tolerance band.

After calibration and reinstallation of the locking uire, the endcrvoltage device pick-up voltage should be rechecked with three (3) quick measurements.

6.1.3 Check dropout voltage of undervoltage device. Allowable values are 30% to 607,(36 - 72 VAC). l 6.1.4 Check the torque required on the trip shaft to trip the closed breaker. This torque should not exceed 1.25 pound-inches. This may be checked with the equivalent of an open end urench fabricated froa a piece of sheet metal to which a spring scale can be fastened approximately 1 inch from the trip shaft cc:nt arline . If the torque required to trip the breaker exceeds 1.25 pound-inches, investigate and repair as necessary.

CAUTION: The latch roller and trip shaft bearings have been replaced en all CR9 trip breakers with bearings containing Mobil 23 grease.

Do IIOT attempt to revitalize the lubricant in these bearings.

Section 6.1 completed by Date 6.2 Inspecting, cleaning, and adjusting.

6.2.1 Pemove are chutes and do a complete visual inspection.

This should not be limited to just a static visual check, but the breaker chould be manually and electrically operated to casure a cicar, free operation in both the I

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4 5 UP 1405.05.3 closing _and opening modes. All nethods of closing and tripping must be checked to ensure proper operation.

Any interlocks that ti;e breaker has. i.e. , breaker withdrawal while in closed position or breaker withdrawal while racked in, cust also be checked for operation.

3 A visual inspection for broken, Icose or missing parts is critical.

This inspection will include viring insulation and termination, all retaining rings, pole bases, statiocary and movable contacts, and tightness of nuts and bolts.

The arc chutes should be inspected to determine their condition. If cracks develop or parts are broken off, the are chutes should be replaced; beads of metal from contact splattering should be renoved.

Excessive black carbon fren arcing can be recoved with light canding.

6.2.2 Hanually operate the breaker three times and check for 3 obstructions, excessive friction, latch engagement, and operating mechanism alignaent and freedom.

6.2.3 Utilize the folloving information and connect the

'a 120V AC or 125V DC power supply to allow electrical cycling of the breaker in Step 6.1.4.

3l TO CLOSE (AC) TO TRIP (DC)

1. Attach + Lead to Al 1. Attach + Lead to A-6

2. Attach - Lead to A4 2. Attach - Lead to A5

3. Jumper Al to A2 3. Energize power supply +

4. Energize power supply Breaker will trip.

5. Press CLOSE Button +

Breaker will close.

6.2.4 Electrically cycle the breaker three tines and check for proper functi, aing of the breaker's electrical system.

3 6.2.5 Discoanect pm -r supplies.

6.2.6 Contact Print - This very simple test involves inserting a piece of bond paper and carbon paper betucen the contacts. Close the circuit breaker, open the breaker, and check the contact print.

A general rule of thumb requires 80% contact surface.

A print will indicate the general condition of the contacts and shou the amount of maintenance or service they need.

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6 MP 1405.03.3 6~2.7

. Clean and inspect the overall breaker. Renove cny I 3 foreign material such as paint, dust, oil or exccasive grease. This chould prevent low resistance betvean points of different potential. Execssive grease and cirt nust be ren>ved from the trip latch surface.

6.2.8 Clean and inspect the "X" relay and contacts. Ensure that there are no loose connections.

0.2.9 Clean and inspect the "Y" relay and contacts. Ensure that there cre ao laose connections.

6.2.10 Clean and inspect the undervoltage trip device.

3l 6.2.11 Cleana'ndinspecttheshukttripdevice. Check / adjust overtravel per GEI-50299 page 20 under (Shunt Trip Device Adjustment).

6.2.12 Clean and check the seccndary disconnects for bad tabs. Ensure the wire connections are tight.

6.2.13 Inspect main contact condition and neasure contact 3l vipe. Proper uipe is 3/32 to 5/32 inch. Replace contacts with less thaa one-half the original thickacas (1/8 inch) of the contact tip material remaining. -

6.2.14 Inspect the primary disconnects. Adequate primary T-contact force is candatory. Proper spring dimension is 13/16 to 27/32 inch. The proper dimensions betucen 3 contact fingera is 7/16". Adjust if necessary.

(Refer to the GE Instruction llanual for primary disconnect replacemeat information if necessary).

6.2.15 Clean all silver to silver friction points (such~

as the primary disconnects) (with scotch brite or equivalcut) and apply a fresh coat of GE Spec. No.

D50II47 lubricant or an equivalent.

6.2.16 Lubricate all bearing points and sliding surfaces very lightly with a thin filn of extreme tenperature, high prernure light grease such as GE Spec. No. .

D50lI15, RPM No. 5, or an equivalent.

3 NOTE: Mobil 28 (GE Company Spec D50ED38) can be uted in place of both the D50lI47 and D50lI15 grease.

6.2.17 Inspect the trip latch engagement for proper latch.

NOTE: If the breaker trips properly with the manual trip button and with the shunt trip

7 MP 1405.05.3 device, D0 NOT rdjust the trip latch ecchanisn.

ifoweve r, if adjustment is necessary, folle:

the L-E instructions specified in G :f-50299.

3l 6.2.13 Inspect the undervoltage trip device to assure there is Nor excessive clearance between the armsture and the rivet and that there is no binding as the armature moves through its t ravel when manu. illy operated.

Optitua:a operating conditions exist when the cicarance between rivet (13) and armature (3) is factory set between 0.001 and 0.010 inches. This clearance dimension cannot be easily measured wiht the undervoltage device installed ia the circuit breaker. The undervoltage 3l device should be removed if necessary and measurcaents raade with a feeler gauge inserted through the side of tLe frame. Measurements should be taken at the outer edges of the armature where a constant radius is in close pro::imity to the rivet. The gap between armature and rivet should be relatively constant for all armature positions.

If adjusbaents are required, proceed as described in Paragraph 1 of the 1979 Service Bulletin.

3 If recommended trip torque reaults (less than 20 i ounce-inches) cannot be obtained, the bearings need to be replaced. No other methods or lubricants should be used.

6.2.19 The adjusteent between the undervoltage trip device and the trip paddle en the trip shaft should be checked to assure the required positive trip is maintained (positive trip exists when approximately 1/32" additional travel of the armature occurs af ter the undervoltage device trips the breaker).

" Positive trip" ensures that during the last part of the armaLure motion sufficient overtravel exists to positively displace the trip latch slightly more than the amount necessary to trip the breaker. This i- overtravel should be 1/32" plus 1/64" minus 0 (i.e.

between 3/64" and 1/32"). With a 1/32" dia uire placed between the open air gap stop and the armature extension, the contact should just start to close when the mechanism is operated to the closed position.

Adjust screu 20 until this condition is obtained.

Uith the wire removed, the breaker should be trip-free with no contact movement or resistance whan the mechanism is operated.

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3 'UP 1405.CS.3 x

6.2.20 Nanually operath the breaker three times. Verify I that the brecher cperates properly and smoothly.

6.2.21 Utilize the following informatica .:nd connect the 3l.-

120V AC or 125V DC power cupply to allow electrical cycling of the breaker in Step 6.1.26.

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'TO CLOSE (AC) TO TRIP (D'C)

1. Attach + Lead to A1 1. Attach + Lead to A6

2. Attach - Lc'ad to A4 2. Attach - Lead to'AS

3. Jumper Al to A2 3. Ener'gize power supply-

4. Energize power supply Ercaher will trip.

5. Press CLOSE Button Breaker will close.

6.2.22 Electrically cycle the breaker twice and verify proper circuit breaker functioning.

-3l 6.2.23 Disconnect the power supt ies and replace the are chutes.

-3 6.2.26 Perform Section 6.1 and record as (As Left).

6.2.25- Mcgger breaker per tIP 1410.33,- and enter results on

-Attachment 1.

6.2.26 Perforn response time test per ST 5030.20.

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Section 6.2 ccepleted by Date 6.3 AKD5.Svitchgear Maintenance NOTE: Section 6.3 will only be perforned during an outage or shutdown condition.

6.3.1 Breaker Compartment Interiors

1. Thoroughly clean interior of the breaker and instrument.

compartments. Use a vacuum cleaner and clean rags only. Do not use stcci wool, or oxide papers.

Blowing uith compressed air is not recommended.

2. Check indicating devices and mechanical interlocks.

3. Check primary disconnecting device contacts for signs of abnormal wear or overheating. Discoloration of the silvered surfaces is not ordinarily harmful.

These contacts should be cleaned only by uiping with a lint-free cloth.

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9 MP 1405.05.3

-4. Before replacicg the breaker, check the align. cent and wipe off the primary disconnecting davice contacts.

Apply a thin coat of contact lubricant. D50!I47 (or

. Mobil 28), to the houce studs and fingers.

6.3.2 Bus Ccapartment

1. Inspect the busses end connections carefully for evidence of over-heating or weakening of the insulating supports.

2. Check that all bua mounting bolts and cplice connection bolts are tight.

3. Wipe and vacumi clean the busses and supports.

4. Check the insulation of the breaker studs that pass through the bus compartment.

5. Af ter cleaning, megger and record the resistance to ground and between phases of the insulation busses

- and connection per tiP 1410.33.

Section 6.3 completed by Date 6.4 Breaker Restoration 6.4.1 Contact the Chif t Supervisor and install the breaker in the cell. ,

6.4.2 Perform a function al test of the breaker per ST 5030.12.

Section 6.4 completed by Date

7. ACCCPTANCE CRITERIA 7.1 All parameters are within tolerance and breaker functional test is satisfactory.

Verified Date Reviewed by Date (Cognizant Engineer)

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~ AD iflld.li.00 10 _ iip 1405.05.3 CRD TRIP LPIAYER -

DATA S! FELT CHMUIL TO. SERIAL N0. DATE 6.1.1 Ifiero-Olnacter test.

Aa Found A B C-As Left.-A B -C (tloninal 0-100 mLcro chms, naximma 400-500 ndcro oluns) 6.1.2 _ Pick-up setting of instantaneous undervolt. age device.

As Found Voltage As Left Voltage (Tolerance 100-106 VAC) 6.1.3 Drop-out cetting of instantaneous undervoltage device.

As Found Vcltage As Left Voltage s i

Tolerance 307,-60% (36-72 VAC) 6.1.4 Torque required to operate trip sitaft.

As Found Torque l As Left Torque (Tolerance 1.25 pound-inches) 6.2.25 Insulation Resistance A B C l

(Ilinimum 2 megohn:s) i ~

6.2.26 Response Time Test l Ibec (Bencit)

f.  !!sec (On-Line)

[ (ifaximum 100 lbec)

+

Completed by_ _

l Attaciment 1 END Page 1 of 1

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