LS3_Exciter_SOW.docx

General Statement of Work for Units LS3 Exciter Reconditioning

1.0 Summary

Perform incoming visual inspection of the main exciter and the pilot exciter armatures and the field frames and PMG, and note any shipping damage and/or problems. Furnish labor, equipment, and materials to clean exciter pieces to remove all contaminates; bake at 225 degrees F maximum temperature to remove all moisture from the insulation; and dip to renew the integrity of the insulation. Neither hydrocarbon based solvents or cleaners, nor any cleaner which dissolves carbon, shall be used to clean the exciter equipment. Only water based cleaners, approved for use on electrical equipment, shall be used to clean the exciter equipment. During dipping and while curing in the oven, DO NOT CONTAMINATE COMMUTATORS WITH VARNISH OR PAINT.

NOTE: On large equipment with aging insulation requiring long dry out times, moisture removal and dryness shall be determined by measuring the galvanic cell voltage between the copper coils in the windings and their respective cores.

Furnish labor, equipment, and materials to test and inspect the exciter pieces in accordance with the attached test forms, and to recondition the exciters to an “as new” a condition as is reasonably possible. The Government will use the test forms to evaluate the condition of the exciters.

After being informed by the Contractor that the exciters are ready for testing and inspection, and at the Government’s option, the Government will send inspector(s) to the work site to witness the after-cleaning tests, and/or to inspect the exciters set after they have been reconditioned and tested.

For the purpose of Government acceptance of the work, and payment for said work, all tests listed in the test forms shall be completed. In addition, all Contractor standard tests shall be performed and documented on the Contractor’s standard forms; said forms shall be attached to the appropriate Government test form.

2.0 Description of Exciter and Recent Operational History

PILOT EXCITER

3.0 Scope of work

3.1 If main exciter and/or pilot exciter armature meggar readings do not improve to acceptable levels after cleaning, unband the armature(s) and clean between the risers, and reband. Use the same type of banding as was installed on the incoming armature, and apply in accordance with Section 3.13 of ANSI/EASA AR100. If meggar readings still remain low, notify the Government of the results and any recommendations for repair. The critical need date for return of equipment is December 30, 2015.

3.2 If rewiring or releading of the pilot exciter fields is required by this specification, or is determined necessary by the Contractor, the Contractor shall wire the field in accordance with LS-3 Exciter wiring diagram 222-117-20624. All pilot exciter leads shall be affixed with a stamped metal tag with the industry designation (See section 4.5) and an additional stamped metal tag with the circuit wire name designation in accordance with drawing 222117-20624.

3.3 If rewiring or releading of the main exciter fields is required by this specification, or is determined necessary by the Contractor, the Contractor shall attach a wiring diagram to the main exciter test form showing how the fields were rewired. All main exciter leads shall be affixed with a stamped metal tag with the industry standard designation and an additional stamped metal tag with the circuit wire name designation in accordance with LS-3 Exciter wiring diagram 222-117-20624.

3.4 MAIN EXCITER

Meggar and perform pole drop tests as applicable on armature and fields. Verify correct polarity of the field pole connections on the two shunt fields before and after any repairs or reconnections are made. Record the readings of the as-found (incoming), the after-cleaning, and the as-left (after sealing windings) conditions of the windings on test form 430-127.

AFTER CLEANING:

Retorque commutator bolts after baking.

After retorqueing commutator bolts, check the heights of adjacent commutator bars to see if any bar-to-bar height variations exceed 0.0005 inch. If variations exceed 0.0005 inch, check for loose bars. If the bars are tight, commutator grinding is required. If the bars are loose, retighten commutator bolts until there are no loose bars, and check bar heights again. Record the bar-to-bar height variations on a separate sheet and attach to form MMB-223B.

Record Ductor readings of the armature coils on a separate sheet, and attach to form 430-127.

Perform Surge Comparison and/or Baker Advanced Winding Analyzer (AWA) Method tests on armature coils. Attach photos and/or report, and a brief narrative of test results to test form 430-127. This same test shall be performed again after the armature has been sealed and cured, to ensure no damage has occurred during the reconditioning process.

Perform high resistance hot test on armature risers to detect any bad connections and cracked or broken riser bars. Attach brief report of findings.

Machine/grind commutator surface to concentricity with shaft centering bores for a runout of 0.001 inch maximum.

Measure and record commutator as-found and as-left diameters and runouts on form MMB-223B.

After machining commutator, undercut mica to a depth of 7/64 (0.1094) inch, +1/64 inch. Check slots with depth gauge and cut out any high mica if depth is not within this tolerance.

Bevel both sides of the commutator slot edges at approximately 45 degrees with a 1/32 inch chamfer.

Inspect and clean all commutator slots and remove any high or side mica and copper tailings from the slots.

If required, fabricate an arbor for machining the commutator surface.

Check rotor balance and dynamically balance it if necessary; notify the Government of any abnormalities.

Perform AC and DC Voltage Pole Drop tests on the main shunt field, the differential shunt field, and the interpole field. Record readings on test form 430-127. The field poles may or may not be numbered. The Contractor shall assign numbers to un-numbered poles, and attach to the test form a diagram of the pole arrangement showing the number and location of each pole.

Perform Polarization Index insulation tests on the armature, the main shunt field, the differential shunt field, and the interpole field. Attach graphs and report to form 430-127. This same test shall be performed after the windings have been sealed and cured.

Measure the DC resistance of the two shunt fields. Record the readings on test form 430-127.

3.5 PILOT EXCITER

Meggar and perform pole drop tests as applicable on armature and fields. Verify correct polarity of the field pole connections on the shunt field before and after any repairs or reconnections are made. Record the readings of the as-found (incoming), the after-cleaning, and the as-left (after sealing windings) conditions of the windings on test form 430-126.

Note: The industry lead designations on the pilot exciter are not standard. The armature leads are A3 (circuit designation PEN) and A4 (circuit designation PEP); the shunt field leads are F5 (circuit designation PEF1) and F6. DO NOT CHANGE THESE DESIGNATIONS. If the leads do not have stamped metal tags with these designations, they shall be affixed with stamped metal tags per the designations above and LS3 wiring diagram 222117-20624.

AFTER CLEANING:

Retorque commutator bolts after baking.

After retorqueing commutator bolts, check the heights of adjacent commutator bars to see if any bar-to-bar height variations exceed 0.0005 inch. If variations exceed 0.0005 inch, check for loose bars. If the bars are tight, commutator grinding is required. If the bars are loose, retighten commutator bolts until there are no loose bars, and check bar heights again. Record the bar-to-bar height variations on a separate sheet and attach to form MMB-223B.

Record Ductor readings of the armature coils on a separate sheet, and attach to form 430-126.

Perform Surge Comparison and/or Baker Advanced Winding Analyzer (AWA) Method tests on armature coils. Attach photos and/or report, and a brief narrative of test results to test form 430-126. This same test shall be performed again after the armature has been sealed and cured, to ensure no damage has occurred during the reconditioning process.

Perform high resistance hot test on armature risers to detect any bad connections and cracked or broken riser bars. Attach brief report of findings.

Machine/grind commutator surface to concentricity with shaft centering bores for a runout of 0.001 inch maximum.

Measure and record commutator as-found and as-left runouts on form MMB-223B.

After machining commutator, undercut mica to a depth of 1/16 (0.0625) inch, +1/64 inch. Check slots with depth gauge and cut out any high mica if depth is not within this tolerance.

Bevel both sides of the commutator slot edges at approximately 45 degrees with a 1/32 inch chamfer.

Inspect and clean all commutator slots and remove any high or side mica and copper tailings from the slots.

If required, fabricate an arbor for machining the commutator surface.

Check rotor balance and dynamically balance if necessary; notify the Government of any abnormalities.

Perform AC and DC Voltage Pole Drop tests on the shunt field and the interpole field at rated voltage and/or amps. Record readings on test form 430-126. The field poles are numbered, and their locations are shown on LS-2 Exciter Wiring Diagram 222-117-20407.

Perform Polarization Index insulation tests on the armature, the shunt field and the interpole field. Attach graphs and report to form 430-126. This same test shall be performed after the windings have been sealed and cured.

Measure the DC resistance of the shunt field. Record the readings on test form 430-126.

3.6 PERMANENT MAGNET GENERATOR (PMG)

AFTER CLEANING:

Inspect the following for condition; record condition of the windings, connections and insulation, testing and inspection should be as specified as accepted national or industry standards. If it’s determined after inspection that the PMG is in a deteriorated condition including but not limited to the following, notify the Government prior to repair.

a) Physical damage

b) Insulation failure

c) Winding of permanent magnet generator deteriorated.

d) Rewiring or releading

e) PMG out of balance (contingent upon if PMG was sent as full assembly)

f) Notify the Government of any abnormalities.

3.7 EXTRA WORK AND DEFICIENT CONDITIONS

The Contractor shall notify the Government as soon as possible when it is apparent that extra work is required that is not in the specified scope of work (e.g., rewinding armatures and fields), or if deficient conditions are found. Deficient means out-of-limit conditions found through inspections or tests performed as specified herein, or as specified in accepted national or industry standards. Deficient also means conditions that would not permit the exciter to be returned to “as-new” condition. Any additional work deemed necessary by the Contractor will be discussed at this time. This additional work may include, but not be limited to:

Rewinding the pilot and/or main exciter armatures, Turning and undercutting the pilot and/or main exciter commutators, Replacing/reinsulating/repairing the iron core(s), Rewinding/releading pilot and/or main exciter field windings, Replacing field pole ground wall insulation as necessary on any/all field windings, Replacing field frame insulators, Reinsulating/repairing brush rigging, and Refilling the commutator(s).

Additional repair items identified during inspection will be addressed after award with a modification. Vendor is not authorized to start repair work without prior approval from a contracting officer.

4.0 INSPECTIONS

The Government reserves the right to witness testing and to inspect the exciter components after cleaning, and to witness final testing prior to shipping to Grand Coulee Dam. The Contractor shall provide two business days’ notice of expected testing times, and provide the same notice for the expected shipping date.

The Government will assign a technical contact/representative to oversee Contractor performance of this Statement of Work after contract has been awarded. The technical representative will monitor each requirement and performance thereof and report to the Contracting Officer/Specialist and the Powerhouse Superintendent on any issues that are of concern.

6.0 WARRANTY

Standard commercial warranty is acceptable.

7.0 SHIPPING/TRANSPORTATION

7.1 The Contractor shall transport the exciter pieces to and from the Contractor’s facility. The Government will prepare the exciter pieces for shipping at Grand Coulee Dam Left Powerhouse and load them on to the Contractor’s truck. The Government will off-load the exciter pieces from the Contractor’s truck upon their return to the Grand Coulee Dam Left Powerhouse.

7.2 All exciter pieces shall be wrapped and sealed in Mobil Wrap or equivalent before transporting. Upon completion of work and testing, the Contractor shall package components and secure them to the truck bed in such a manner as to prevent damage from weather and transportation hazards. Packaging methods must be adequate to assure that all pieces, parts, and integral components are well protected from the elements and all road hazards, and to ensure their safe arrival at Grand Coulee Dam.

8.0 TEST & RUNOUT FORMS

9.0 REFERENCE DRAWINGS