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Quality Assurance checks for Induction Motor / Synchronous Motor

1. Electric Motors along with required accessories shall be of proven design and areto be tested for final test at shop according to IS-325, IEC-60034 or equivalent International standard.

2. The final test applicable for all rating of motors shall be as follows:

i. Verification of rating, type and degree of protection as specified.ii. Measurement of overall dimensionsiii. Measurement of Resistanceiv. Measurement of Insulation Resistance before and after High Voltage

test.v. No load run test with measurement of voltage, current, power, vibration

ensuring free / smooth running and phase sequence check.vi. Locked rotor test at reduced voltage.

3. The final test applicable for HT Motors in addition to above shall be:

i. Tangent delta test carried out on each phase or complete winding.ii. Partial discharge test on each phase or complete winding.iii. Polarisation index which shall be greater than 2 (two).iv. Shaft voltage measurementv. IR for RTD, BTD and space heater.

4. The electric motors are to be manufactured as per Quality program involvingchecks during receipt of material, in process, assembly and final testing. An

indicative program is as below; however this shall not be limiting themanufacturer to adopt their best practices and detailed program as per their manufacturing processes and design to be followed. Quality plan for motorsabove 75 KW are required to be approved. The sources of major components like shaft, stamping, bearing, insulated copper conductor, arealso required to be approved for HT Motors.

i. Stator frame, End shields, bearing covers, Terminal box, Coolertubes & body :

The components (caste or fabricated) shall be free from surface/ internal

defects. Plates of thickness greater than 40 mm to be tested by Ultrasonictest. Samples shall meet the Mechanical and Chemical properties. Sufficientclearances to be maintained for machining and in case of heat treatment as

per defined process, records shall be maintained. In case of welding sameare to carried out by qualified welder as per weld procedure in line withASME IX and the weld joints shall be checked for defined NDT test. Thedimensions after machining shall be within specified fitment tolerances.

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Gasket used shall meet the hardness, compression and ageing properties.Coolers for HT motor to be hydraulic tested to ensure free from leakage.

ii. Magnetic material :

Magnetic sheet shall have loss value and thickness as per design and tolerancespecified. The staking factor shall be as per standard referred. The varnishshall be checked for viscosity. The varnished punching shall be checked for dimensions include burr level and coating thickness.

iii. Shaft, fan, Short circuit ring :

The material forged or rolled as per design shall be free from internal andsurface defects when checked by NDT / DP/ MPI / UT. The sample whentested shall meet the desired mechanical and chemical properties. Themachined shaft shall be measured for run out which shall be within specified

limits. In case of welding same are to carried out by qualified welder as per weld procedure agreed and the weld joints shall be checked for defined NDTtest. The heat treatment if any shall be as per defined process. Balancing of shaft, fan is to be carried out to meet the level G 2.5 as per VDI 2056 or

better. The fan blades, hubs shall be suitably locked to the main shaft andtested for over speed test.

iv. Stator Copper Conductor, Rotor copper / Aluminum :

The material / grade used shall meet the conductivity, mechanical andchemical properties as per design. The insulation shall meet the specified classof insulation with their checks for dimension, thickness, dielectric, adhesion.

v. Stator core :

The stator core shall be stacked ensuring slots and ducts free from burrs andusing proven locking mechanism. The build core shall be tested for hot spot,core loss as per practice, rating of motor.

vi. Stator bars/ winding :

The stator bars insulation shall meet the specified class of insulation and the process specified. The varnishing is to be controlled as per defined process.The brazing joints shall be free from cold joints. The stator bars / wound stator to be checked for resistance, dielectric, surge test, Tan delta

vii. Bearing :

The bearing in case of Babbitt shall be ultrasonically tested; the bearingclearances and lubrication are to be maintained as per defined process

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parameters. The sleeve bearing pedestal shall be checked for kerosene leakagetest.

viii. Accessories :

RTD, BTD, Gauges, CT, Lugs shall be provided of proven approved makeand of required rating

iix. Field Quality plan

A detailed Field Quality program for receipt, storage and erection at site as per manufacturers Manual and recommendation to be implemented.

05 The type test requirements are specified else where in this specification