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PREVENTATIVE MAINTENANCE PROCEDURE PM-105 FLORIDA POWER CORPORATION CRYSTAL RIVER UNIT 3 INSULATION RESISTANCE, CONTROL CIRCUITS, HIGH POTENTIAL TEST!NG, INSPECTION, CLEANING, AND DRYING WINDINGS OF ELECTRIC MOTORS THIS PROCEDURE ADDRESSES SAFETY RELATED COMPONENTS THIS PROCEDURE ADDRESSES ENVIRONMENTALLY QUALIFIED (EQ) EQUIPMEN l
l APPROVED BY: Responsible Section Superintendent Supervisor l
8703130236 G70305
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.[ M PDR ADDCH 0S000302 Date M - f-INTERPRETATION CONTACT: Nuclear Maintenance Superintendent
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1.0 PURPOSE 1.1 To provide instructions for testing the winding insulation resistance, high potential testing, inspection, cleaning, and drying of 6.9 kV, 4.16 kV, 480V and 120V electric motors.
Sect: n Maintenance Item 7.1 Using Standard Meggers - General 7.2 Insulation Resistance of Electric Motors 7.3 High Potential Testing of Electric Motors 7."
Inspection and Cleaning of Electric Motors 7.5 Drying Windings of Electric Motors Inspection and Cleaning of Electrical 7.6 Control Circuits
2.0 REFERENCES
2.1 IMPLEMENTING REFERENCES 2.1.1 CP-113, Handling and Controlling Work Requests and Wcrk Packages 2.1.2 CP-115, In-Plant Equipment Clearance and Switching Orders 2.2 DEVELOPMENTAL REFERENCES 2.2.1 Allis-Chalmers Motors, Plant Library Manual Number 226 Electric Machinery Company Motors, Plant Library Manuals.
2.2.2 Numbers 64 and 65 PM-105 Rev. 12 Page 1
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2.2.3 IEEE Standard 43, Recommended Practice for Testing Insulation Resistance of Rotating Machinery 2.2.4 IEEE Standard 95, Recommended Practice for Insulation Testing of Large AC Rotating Machinery with High Direct Source Voltage 3.' ENCLOSUMM 3,1 Enclosure 1 Electric Motor Drying out Data Sheet 3.2 Enclosure 2 Temperature Conversion Chart 4.0 LIMITS AND PRECAUTIOH1 4.1 Do not use a "segger" tester whose terminal or operating voltage is in exces's of that which is safe to apply to the equipment to be tested.
4.2 Megger 120V motors at 500V; 208-220 motors at 500V; 480V motors at 1.000V; and 4.16 kV and 6.9 kV motors at 2500V.
NOTE: All DC actors shall be neggered at 500v unless author-ized by the Nuclear Electrical /IC Supervisor.
4.3 In order to obtain accurate trending data, insulation resis-tance testing should be done within one hour of de-energi:Ing equipment whenever oossible.
PM-105 Rev. 12 Page 2
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4.4 Control complex chiller compressor motors are megged with the stator at ambient temperature after 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> idle standby without water flow through the unit. The unit must be at a positive pressure during the megging operation.
When work is performed on energized equipment, such as termi-4.5 nals, cables, busses, or cubicles, or when work is performed on or around batteries, all tools, tool boxes, and other equipment used must be insulated.
4.6 prior to performing insulation checks on equipment where multi-ple clearances are in ef f ect, the man in charge must assure that the following has been completed.
4.6.1 All clearance holders have been notified.
4.6.2 All open or exposed switchgear, cubicles and terminal points are flagged or roped off and appropriate signs' are posted.
4.6.3 One af the work group personnel is posted within sight of equipment being tested and radio contact has been made between equipment being tested and person responsible for testing.
4.7 For CR-3 equipment designated as "QQ* on the Safety Listing that requires replacement parts, work shall be handled througn Cp-113, Handling and Controlling Work Requests and Work pack-ages.
4.8 Electric motors designated as "QQ" on safety listing, perform-ance of pM-105 is a requirement in order to maintain env;ren- ,
mental qualifications. If it is not possible to perform this pM on the assigned date, notify the Nuclear Electrical Super- i visor so he can arrange to have this pM done as socn as l j
possible.
12, page 3 PM-105 Rev.
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, ,s .g,. ; ._ .g33 . y 5.0 EOuir .n1 kun PFERONNEL REOUTRDIENTS 5.1 Personnel assigned shall be knowledgeable, experienced and qualified to perform the specified tasks as determined by the appropriate supervisor.
5.2 Potential of 500v up to 2500v megger with test leads.
5.3 Hand Tools 5.4 Grounding Jumpers 5.5 HiPot Test Set.
5.6 Clean Rags 5.7 Technical Services-approved solvent and guidelines for use.
5.8 Bucket of Demineralized Water 5.9 Stainless Steel Wire Brush 5.10 Rubber High/ Low Voltage Gloves 5.11 Insulated Mat 6.0 REOUTRED INITTAL CONDITIONS AND PLANT STATUS
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6.1 The equipment to be worked on is to be isolated and removed from service using an approved Operating Procedure and/or an Equipment Clearance Order per CP-115, In-Plant Equipment Clear-ance and Switching Orders, if required.
6.2 If required, obtain a Radiation Work Permit (RWP).
l PM-105 Rev. 12 Page 4
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7.0 PROCEDURE 7.0.1 Ensure c Limits and Precautions of Section 4.0 have been reviewed ar.d implemented.
Step 4.6.1 Completed By Date Step 4.6.2 Completed By Date Step 4.6.3 Completed By Date o Equipment and Personnel are available per Section 5.0.
o Initial Conditions of Section 6.0 have been met.
Completed By Date 7.1 USING STANDARD MEGGERS - GENERAL Place the instrument on a firm and fairly level base. Avcid 7.1.1 f
large masses of iron and strong magnetic fields.
NOTE: The pointer may appear to stand anywhere over the scale i until the instrument is operated because the megger chameter has no control spring.
1 Page 5 PM-105 Rev. }g
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7.1.2 Connect leads to motor to be tested as follows:
NOTE: Motor must be taken out of service and disconnected electrically from all other equipment.
7.1.2.1 Connect the " Earth' lead to the case or foundation of the motor.
7.1.2.2 Connect the 'Line' lead to the conductor of the motor.
NOTE: On three-phase actors, each phase should be tested separately althouga all three (3) leads may be tied together and tested at one time. On DC actors, initial test is with brushes on commutator.
Page 6 PM-105 Rev. J2
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7.2 ur1CUmTNG TNSUuTION RESISTANCE OF Ftr m IC le0 TORS 7.2.1 Operate the aegger and take resistance readings only af ter it becomes steady. Record resistance readings below.
Test Inst. No. Cal. Due Date Meggar Voltage Insulation Resistance Megehas Notes NOTE: If the insulation resistance is less than 1 segohn per 1,000V rating, or 1 segohn, whichever is greater, notify the Electrical Supervisor.
Completed By Date 7.2.2 Repeat Step 7.2.1 for each phase on AC motors if each winding is tested separately.
(2nd Phase 3rd Phase ) as required).
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l 7.2.3 On DC motors, repeat Step 7.2.1 with brushes lifted off commutator if unsatisfactory value was obtained.
7.2.4 Upon completion of megger test, separate leads and return l equipment to original configuration.
1 Completed By Date Rev. page 7 PM-105 }2 l
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7.3 EIGE Mzn1W. TESTING OF FT FCTRIC HOTORS 7.3.0 Discussion from IEEE Std 95-1977, Recommended Practice for Insulation Testing of Large AC Rotating Machinery With liigh Direct Voltage. ' Direct voltage acts to search out a faulty area in the insulation by establishing leakage current frcm that area. Although small currents may aqqravate damage and lead to breakdown if the voltage is raised to a high enough level, this usually does not occur unless the weakness is significant and should be found.'
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CAUTION: Personnel performing the high potential testing must wear rubber high voltage gloves while connecting and disconnecting the Ei Pot Test set leads and stand on an insulated sat during the test.
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NOTE: Prior to performing a high potential test, a PI index aust be determined as follows:
- a. Attach a megger per Section 7.1 and 7.2 and supply 2500V.
10
- b. Take a resistance reading at 1 min. and again at min.
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- c. Divide the 10 min. reading by the 1 min. reading to determine the PI index.
- d. If the PI index is _{ 1.5, contact the Electrical Supervisor before any high potential testing is attempted.
- e. Contact Elec Supervisor for proper test voltage to be used.
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Turn " Voltage Adjust" knob to minimum voltage. [12 7.3.1 7.3.2 If " Remote' switch is to be used, plug into " Remote" jack.
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(See Step 7.?.6 7.3.3 Record test data for the motor to be tested.
for appropriate values.) Record value below.
Test Inst. No. Cal. Due Date Current Limit Microamps
2 Test Voltage Notes Completed By Date 7.3.4 Connect the high voltage lead to the conductor of tne mo ::
Ensure motor is out of service and. disconnected electrica;;y from all other equipment.
NOTE: On three-phase motors, each phase should be tested separately although all three (3) leads may be tied together and tested at one time.
7.3.5 Connect the return for the leakage current to be measured to the ground lead.
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"High Volt" switch and aradually increase the 7.3.6 Turn on
' Voltage. If desired test voltage cannot be reached without l1; exceeding current limit values, notify Electrical Superviscr ,
before continuing test.
NOTE: For new installations, desired test voltage is twice the rated voltage plus 1,000V times 0.85 times 1.7 held for 60 sec., i.e.:
Normal Volts Test Volts current Limit uA ,
120 1,791 30 480 2,832 100 4,160 13,467 300 6,900 21,386 300 NOTE: For existing installations, desired test voltage is 125*.
of rated voltage times 1.7 held for 60 seconds, i.e,:
Normal Volts Test Volts current Limit uA 120 255 30 480 1,020 100 l
4,160 8,840 300 6,900 14,662 300 i
{ For special testing, test voltages will be determined by the l
j Nuclear Electrical Supervisor.
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7.3.7 The 'DC Micreamps' display will indicate the leakage current in the circuit under test.
7.3.8 Release the "High Volt" switch and record test voltage and leakage current below.
Test Inst. No. Cal. Due Date j '2 Current Limit Micreamps Leakage Current Test Voltage Notes NOTE: Allow sufficient time for the high voltage to reduce to a low value.
Date Completed By l
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7.3.9 Ground the motor leads and leave grounded for a period of five (S) times the length of time the motor was energized.
NOTE: This is required as some dialectrics will return a test circuit to a potential of several hundred volts after it has been shorted briefly, due to polarization relaxation in the dialectric.
7.3.10 Repeat Steps 7.3.4 thru 7.3.9 for each phase of the AC m:: Or.
if each winding is tested separately.
7.3.11 Upon completion of high potential test, return equipment to original configuration.
Completed By Date 7.4 INSPECTION AND PLEANING OF ELECTRIC MOTORS 7.4.1 Check the motor for the following conditions and rec 0rd the results after each step.
7.4.1.1 With motor not running, check space heater electrically usin; amp probe.
NOTE: On a motor that is inaccessible; check current on heater Current circuit at motor control station on starter.
will be on the order of approximately 0.10 amps, page 1:
pM-105 Rev. 1g
7.4.1.2 Tag out equipment in accordance with CP-115, In-Plant Equipment Clearance and Switching orders.
7.4.1.3 Check the motor for loose or damaged cables or condult.
Sat. Unsat. Notes Completed By Date 7.4.1.4 Check the actor for proper ventilation. Inspect ventilation screens or openings for cleanliness.
Sat. Unsat. Notes Completed By Date 7.4.1.5 Visually check the motor for a buildup of dust, dirt, or rus:.
Check motor for water, oil, or other contamination.
Sat. Unsat. Notes Completed By Date 7.4.2 If cleanliness is judged to be unsatisf actory, clean ac:crd:ng to the following procedure.
Sat. Unsat. Notes Completed By Date PM-105 Rev. 12 Page 13
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7.4.2.1 If contamination is by loose dust or dirt, use a vacuum cleaner; or clean, dry cloths for removal, compressed air can be used with caution.
NOTE: Compressed air used should be clean and dry (instrument air) and at a reduced pressure of approximately 25 psig.
Avoid blowing dust from one nachine to another. Cloths should be clean and free of any lint. When using compressed air, wear safety goggles. Motors that have run in the Radiation controlled Area (RCA) require special consideration prior to cleaning. Insure Realth Physics is aware if compressed air is to be used.
7.4.2.2 If accumulated dirt contains grease or oil, a solvent will probably be necessary. Note that high terperature insulations of the ' silicone
- type require special solvents which do not t
attack the varnish. Consult manufacturer's recommendations.
NOTE: Obtain Health Physics approval for any solvent used in an RCA.
7.4.2.3 Water can be used to wash out motors that have been plugged with aud or other foreign matter. Water may be applied with a hose at reduced pressure. Af ter any cleaning operation with water, the surface moisture should be wiped off with a clean cloth and the insulation dried promptly.
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7.4.3 After any cleaning which may reduce insulation resistance, check resistance per Section 7.1 and 7.2.
Sat. Unsat. Notes Completed By Date 7.4.4 Restore equipment to normal operation.
Sat. Unsat. Notes Completed By Date .
7.4.5 While motor is in operation, listen for any unusual noises.
7.4.6 After operation until temperatures have stabilized, physically If feel the motor for excessive heat or excessive vibration.
either is suspected, notify the Electrical Supervisor.
7.4.7 Sign and date below.
Completed By Date .
PM-105 Rev. Ib Page 15
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7.5 navilec vTunincs or uv.rcTmic noTons After an electric motor has been cleaned, before it is placed in operation, the insulation must be dry. There are many methods of applying heat to a motor, both externally and internally. The preferred type of each is procedurally described herein. If other methods are required, then permis-sien must be obtained from the Electrical Supervisor prior to proceeding.
7.5.1 Drvina with External Heat 7.5.1.1 Determine heater (KW) capacity by multiplying the total outside I
area of the end bells of the motor, in square feet, by the desired degrees Centigrade rise and divide by 1,000.
EXAMPLE: (4 ft.2)(50*c) = 200 watts 1,000 f
NOTE: Motor temperature will be raised to 85*c during the drying out process.
7.5.1.2 Suspend space heaters under the end windings and provide ventilation to circulate the air.
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7.5.1.3 Connect a 'negger* Per Section 7.1.
7.5.1.4 Arrange the instrument and test leads and one (1) or more thermometers so that frequent readings can be made quickly and easily as drying progresses. Use installed RTD's if available.
NOTE: Leave the "negger" tester connected for the duration of the heat run.
7.5.1.5 Record insulation resistance readings every 4 hrs. on Enclosure 1 while the drying-out run is in progress.
7.5.1.6 Turn on the heaters and slowly raise the temperature of the end winding insulation. During heating, temperatures should net exceed 85'C.
7.5.1.7 Maintain 85'c until the insulation resistance has dropped to the minimum and then increased to a satisfactory value.
NOTE: This may occur before a temperature of 55'c is indicated on the armature punchings.
NOTE: Satisfactory value is at least 1 megohn for each 1,000V j
operating voltage but not less than 1 segohn regardless I
of voltage.
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7.5.1.8 Continue the drying-out run until both the insulation resis-tance and the temperature have become constant and remain constant for several hours.
7.5.2 nrvina with Internal Heat NOTE: Extreme caution must be exercised when drying out with internal heat since the heat generated in the inner parts is not readily dissipated. This results in gas and vapor generation within the insulation and possible breaking the continuity of the layers or actual rupture of the material. Therefore, this procedure shall only be performed under the cognizance of an Electrical Supervisor.
7.5.2.1 connect a DC welding nachine to the motor windings. Set ar.perage at one-third of motor rating.
l 7.5.2.2 Set up a 'megger' per Section 7.1 and 7.2 using alligator I
clips.
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i PM-105 Rev. 10 Page 18
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7.5.2.3 Arrange the instrument and test leads and one (1) or more thermometers so that frequent readings can be made quickly and easily as drying progresses. Use installed RTD's if available.
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CAUTION: De ant leave the "megger" tester connected while circulating current with the welding nachine.
7.5.2.4 Record insulation resistance readings every 4 hrs. on Enclosure 1 while the drying-out run is in progress.
7.5.2.5 Ensure the "negger" is disconnected and then turn on the DC welding nachine.
7.5.2.6 Maintain winding tempert*.ure less than 65*C as determined by the Electrical Supervisor until the insulation resistance has dropped to the minimum and then increased to a satisfactory value.
NOTE: This may occur before a temperature of 55'c is indicated on the armature punchings.
NOTE: Satisfactory value is at least 1 segohn for each 1,000V operating voltage but not less than 1 megohn regardless of voltage.
PM-105 Rev. 1b Page 19
7.5.2.7 Continue the drying-out run until both the insulation resis-tance and the temperature have become constant and remain constant for several hours.
7.5.3 Upon completion of the drying-out run, restore equipment to original configuration.
EM-7. INEPECTION AND ctEANING OF FLECTRICAL l11 7.6 ,'
CONTROL CIRCUITS 7.6.1 visual Inspection ,
7.6.2 Open the control cabinet to gain access to the control circuits to be inspected.
the control circuits for signs of overheating.
7.6.3 Check discoloration, odors, or cracked insulation.
7.6.4 Check the control circuits for foreign object damage.
7.6.5 Check the control circuits for deterioration and rust.
7.6.6 Using care not to break or damage any components or wir:n; vacuum the control circuit cabinet.
ti:w 7.6.7 Using low pressure air or nitrogen (25 psig or less remaining dust or dirt from the cabinet. l 7.6.8 Check terminal block links to insure that they are closed and tight.
PM-105 Rev. 1g Page 20 (Continued on Page 20a)
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7.6.9 #Check control fuses per CAI 55-224-003 fuse list. l11' _
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Completed By y Date , [1?
5 8.0 POST-MAINTENANCE TESTING A180 STSTDI RESTORATION E M '
8.1 Any testing and restoration required in the t:ocecure* portion of this procedure is complete.
8.2 Release Clearances per requirements of CP-115. In-Plant Equ.p ment Clearance and Switching Orders if issued.
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- ,s Page of ELECTRIC MOTOR DRYING OUT DATA S3EET s
MAIN 7JffANCE SUPV./
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