Page 1 of 11
Subject: Polarization Index Testing of Motors
Revision Number and Date: R 0
TBD
Procedure No.: LUM-FFA-MNT-0021
Use: Reference Use
Effective Date: TBD
Prepared by: Jerry Wayne
Date: ____________________
Reviewed by: ___________________________________________________ Date: ____________________
Approved by: ___________________________________________________ Date: ____________________
Required review frequency: TBD
Page 2 of 11
Subject: Polarization Index Testing of Motors
Revision Number and Date: R 0
TBD
Procedure No.: LUM-FFA-MNT-0021
Use: Reference Use
Table of Contents
1. Purpose and Scope ......................................................................................................................................... 4
2. Acceptance Criteria........................................................................................................................................ 4
3. Special Tools and Materials ........................................................................................................................ 4
3.1 Tools .......................................................................................................................................................................... 4
3.2 Materials .................................................................................................................................................................. 4
4. Precautions, Limitations, and Notes ........................................................................................................ 5
4.1 Precautions............................................................................................................................................................. 5
4.2 Limitations.............................................................................................................................................................. 5
4.3 Notes ......................................................................................................................................................................... 5
5. Prerequisites.................................................................................................................................................... 6
5.1 Planner ..................................................................................................................................................................... 6
5.2 Electricians ............................................................................................................................................................. 6
6. Definitions and Acronyms ........................................................................................................................... 7
7. Instructions ...................................................................................................................................................... 7
7.1 Polarization Index ............................................................................................................................................... 7
8. References......................................................................................................................................................... 9
8.1 Development References .................................................................................................................................. 9
8.2 Performance References ................................................................................................................................... 9
Attachment A: Data Sheet ................................................................................................................................................. 10
Revision History..................................................................................................................................................................... 11
List of Figures
None
List of Tables
Table 1: Signature Box........................................................................................................................................................... 6
Table 2: Test Voltages ............................................................................................................................................................ 7
Page 3 of 11
Subject: Polarization Index Testing of Motors
Revision Number and Date: R 0
TBD
Procedure No.: LUM-FFA-MNT-0021
Use: Reference Use
Reviews
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stored in <type location where comments are stored.>.
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Internal Review
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03/01/11
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Page 4 of 11
Subject: Polarization Index Testing of Motors
Revision Number and Date: R 0
TBD
Procedure No.: LUM-FFA-MNT-0021
Use: Reference Use
1. Purpose and Scope
The purpose of this procedure is to provide instructions for performing a Polarization Index (PI)
test of motor insulation and a place to document the data collected.
2. Acceptance Criteria
The following acceptance criteria must be met to complete the procedure. The PI shall equal or
exceed 2.0 or manufacturer's recommendations if specified. (If the one-minute insulation resistance
value is above 5000 megohms, the calculated PI may not be meaningful. In such cases, the PI may be
disregarded as a measure of winding insulation condition.)
3. Special Tools and Materials
Use the following special tools and materials to perform this procedure.
3.1 Tools
The following special tools are required:



Digital Multi-Meter (DMM)
Megger (500 VDC to 10,000 VDC)
Timing device (stopwatch)
3.2 Materials
The following special materials are required:





Hot stick
Grounding stick
Ground jumpers
Class II insulated gloves with leather protectors
Insulating material (7.5KV PVC insulating roll, made by Certified Insulated Products,
code #20307)
Page 5 of 11
Subject: Polarization Index Testing of Motors
Revision Number and Date: R 0
TBD
Procedure No.: LUM-FFA-MNT-0021
Use: Reference Use
4. Precautions, Limitations, and Notes
Before performing the procedure, ensure you understand the following precautions, limitations,
and notes.
4.1 Precautions
The following precautions shall be followed:




Do not perform insulation test in a flammable or explosive atmosphere.
Wear Personal Protective Equipment (PPE) and Electrical Protective Equipment (EPE) when
meggering and when connecting or disconnecting meggering equipment rated above 2500
volts.
Establish barriers and flagging to warn and keep other personnel away from equipment
during insulation testing and during a capacitance discharge.
Maintain minimum approach distances to exposed live parts as follows unless you are using
proper protective equipment:
o
o





0- 1000 volts
avoid contact
1001-15000 volts 2 feet 1 inch
A supervisor must be present when working with equipment energized at 600 volts or
more.
Connect ground lead first, and then HV lead. Disconnect ground lead last.
Ground motor to discharge accumulated electrical charges for safety of personnel and for
test accuracy. Apply ground for four times the length of time you performed the test.
Establish a solid connection to earth ground for both PI and discharge of voltage. Use motor
frame for ground when meggering de-terminated motors.
Be aware that other voltages may be present if working from switchgear: DC control power,
space heaters, alarm circuits, and convenience outlets.
4.2 Limitations
The following limitations may occur while performing the procedure:

None
4.3 Notes
The following information is to be used while performing the procedure:


Consider equipment to be energized until grounded. When removing grounds, equipment
should be considered energized at the moment of ground removal.
Steps in this procedure may be re-performed as necessary to obtain satisfactory results.
Page 6 of 11
Subject: Polarization Index Testing of Motors
Revision Number and Date: R 0
TBD
Procedure No.: LUM-FFA-MNT-0021
Use: Reference Use


Check that all calibrated equipment has a current Due Date.
Report unsatisfactory test results to the Electrical Supervisor for follow-up actions and to
write a CR.
5. Prerequisites
The following prerequisites must be met before performing this procedure.
5.1 Planner
The planner must enter the following information:




Work Order No.: __________________________________
Component Tag No.: ______________________________
Unit No.: ____________________________________________
Serial No.: __________________________________________
5.2 Electricians
Personnel performing this procedure shall review all instructions, precautions, notes, and safety
requirements prior to performing this procedure.
Each person performing work using this procedure is required to record his or her name in the
following signature box (see Table 1: Signature Box). If a RACF ID is unavailable, include the contact
information of the individual.
Print Name
Table 1: Signature Box
Sign Name
Initials
RACF ID
Page 7 of 11
Subject: Polarization Index Testing of Motors
Revision Number and Date: R 0
TBD
Procedure No.: LUM-FFA-MNT-0021
Use: Reference Use
Determine the proper test voltage for the motor using the Table 2: Test Voltages. Record this value
on the Attachment A: Data Sheet.
Bus Voltage
Test Voltage DC
480
500
2500
2500
4160
5000
6900
5000
13800
10000
Table 2: Test Voltages
6. Definitions and Acronyms
The following definitions and acronyms appear throughout this procedure. The first occurrence of
each term and acronym appears in italics.
DMM—Digital Multi-Meter
EPE—Electrical Protective Equipment
L-D-L—Live-Dead-Live
PPE—Personal Protective Equipment
PI—Polarization Index
Resource Access Control Facility Identification (RACF ID)—Computer logon identification and
authentication code
7. Instructions
The instructions below are for the following task:
7.1 Polarization Index
Note 1 Perform a PI while the motor is still warm to preclude condensation or the absorption of
moisture.
Page 8 of 11
Subject: Polarization Index Testing of Motors
Revision Number and Date: R 0
TBD
Procedure No.: LUM-FFA-MNT-0021
Use: Reference Use
1. Verify LOTOV to ensure motor feeder breaker is in Disconnect or Remove position.
2. Ensure load side connections of breaker cubicle are de-energized by electrical
measurement. Use L-D-L method.
Caution
If exposed voltages or test voltages exceed 600 volts, a supervisor must be present
during testing.
3. If you are working in switchgear with the breaker removed, install a cover over the
exposed bus stabs to prevent contact with energized buss. Use an acceptable insulating
material. An alternate method is to work from the back side of that switchgear cubicle
for motor. Be certain of cubicle location and know where the energized bus is.
4. Perform a continuity check between all phases of motor field cables: A-B B-C C-A. If a
discontinuity exists, stop and tell your supervisor.
5. Ensure insulation surface of phase leads is clean and dry.
6. Connect a grounding lead on conductors from all phases to ground. Leave grounds in
place for approximately 10 minutes.
7. Remove all ground leads installed in previous step.
Caution
If test voltages are above 2500 volts, use all PPE, EPE, and Class II gloves when you
connect and disconnect meggering leads.
8. Connect megger ground lead to ground.
9. Connect megger voltage lead to any one phase.
10. Apply test voltage as determined using Table 2: Test Voltages and record the reading
here at one minute and then at the ten-minute point.
1 minute reading: ________ Megohms
10 minute reading: ________ Megohms
11. Using PPE, EPE, and Class II gloves, disconnect megger leads.
Note 2 Grounding will not be required when the equipment is immediately restored to normal
operating conditions and no work is to be performed on the equipment.
12. Use the grounding stick to ground the motor to discharge accumulated charge for
approximately 40 minutes.
Page 9 of 11
Subject: Polarization Index Testing of Motors
Revision Number and Date: R 0
TBD
Procedure No.: LUM-FFA-MNT-0021
Use: Reference Use
13. Remove the ground lead.
14. If used, remove any insulating material or cover that was installed in Step 7.1.3.
15. Calculate the PI as follows:. divide the reading taken at 10 minutes by the reading taken
at 1 minute (PI = 10 min reading / 1 minute reading). Record value here and on
Attachment A: Data Sheet. _______:_1_
16. Check the calculated PI against the acceptance criteria given in Section 2.
17. Perform a closeout inspection of switchgear and work area.
8. References
Development references are documents used to develop the procedure. Performance references are
documents referenced within the procedure.
8.1 Development References
[1]
[2]
[3]
[4]
[5]
Generation Safety Handbook
LUM-FFA-REL-0014 Standard of Human Performance Improvement
IEEE Std 43-2000 Recommended Practice for Testing Insulation Resistance of Rotating
Machinery
MSE-G0-4213 Polarization Index Testing of Motors (from Comanche Peak NPP)
STA-124 Electrical Safe Work Practices (from Comanche Peak NPP)
8.2 Performance References
[1]
STA-124 Electrical Safe Work Practices (from Comanche Peak NPP)
Page 10 of 11
Subject: Polarization Index Testing of Motors
Revision Number and Date: R 0
TBD
Procedure No.: LUM-FFA-MNT-0021
Use: Reference Use
Attachment A: Data Sheet
Equipment Tag Number ________________________
Work Order Number ___________________________
Step No.
Data
5.2
Table 2: Test Voltage: ________________ VDC
Initials
7.1.1
Breaker in Remove or Disconnect position
7.1.4
Continuity:
7.1.10
One minute reading -
Megohms
Ten minute reading -
Megohms
Satisfactory
7.1.15
Calculated PI
7.1.16
Meets acceptance criteria -
7.1.17
Closeout inspection.
Yes
No
Unsatisfactory
_______: 1
Yes
No
Equipment Tag Number ________________________
Step No.
Data
Initials
5.2
Table 2: Test Voltage: ________________ VDC
7.1.1
Breaker in Remove or Disconnect position
7.1.4
Continuity:
7.1.10
One minute reading -
Megohms
Ten minute reading -
Megohms
Satisfactory
7.1.15
Calculated PI
7.1.16
Meets acceptance criteria -
7.1.17
Closeout inspection.
Yes
Unsatisfactory
_______: 1
Yes
No
No
Page 11 of 11
Subject: Polarization Index Testing of Motors
Revision Number and Date: R 0
TBD
Procedure No.: LUM-FFA-MNT-0021
Use: Reference Use
Revision History
Revision Number
Approval Date
Name
Changes
R0
TBD
Jerry Wayne
Initial Draft