fdf-motor repair report - fletcher...

Electro - Mechanical Repair Report

Customer Date

Make

Power (Kw)

Frame

Speed (rpm)

Outgoing Photo

Order Number

Job No

Model

Voltage (v)

Freq (Hz)

Current (A)

Mounting

Fletcher Moorland Ltd. Elenora Street, Stoke on Trent, ST4 1QGTel - 01782 411021 web - www.fletchermoorland.co.uk

Reported Faults / Customer Observations / Reason for Removal

Description

5071258

415v (Y/YY dual winding)

50

19,3 / 75

Flange V5

Reported fault from customer engineer - suspected bearing failure due to excessive noise coming from the motor.

2 Speed AC Motor

24 November 2009

Loher

10 / 45 Kw

A280SA-4/2 HV

1465 / 2930

59798


Incoming Photo Stripdown report

Failure Photo Failure Analysis

Repair Carried Out

Inspection

Repair / Service

Parts Fitted

The motor was dismantled and inspected. There was evidence of a slight oil/water contamination in the motor. The bearings were removed from the rotor and it was evident the drive end bearing had failed.

The drive end SKF NU316ECP roller bearing was investigated, the lubricant was contaminated and the fibre cage had failed. There was evidence of the rollers skidding on the outer race of the bearing (seen on further photos).

The failing bearing was detected early and the motor was removed before any major damage was caused, we believe the motor was only days away from failure.

In our opinion failure of this motor is down to failed lubrication caused by contaminate.

All repairs carried out by Fletcher Moorland are to best practice and follow the strict SKF certified rebuilder requirements.

Following stripdown, the motor internals and externals were blast cleaned. The motor windings were statically tested (Resistance, Megger, HI-POT and Baker Surge) for each winding on this 2 speed motor. All mechanical fits were checked against a fit table and were within tolerance. The rotor was checked and balanced to an enhanced G1.0 balance specification for lower operating vibration. All motor internals were sprayed with and anti-track paint. Genuine SKF bearings were fitted to the rotor and the motor was rebuilt. Fresh lubricant was pumped into the bearings and chambers. The inductive pick-up sensor was checked and tested for operation and re-fitted to the motor. The pulley was cleaned and checked then fitted to the motor. A full run test was carried out at both speeds (2 & 4 pole). All mechanical vibration and bearing checks were carried out. The motor was painted then dispatched to your site.

SKF NU316ECPSKF 6313 C3

Mechanical Fit Data

Nominal mm

Up Tol

Lo Tol

Pass Fail

Shaft size

Keyway

Shaft run-out

Pass Fail

Pass Fail

Pass Fail

Pass Fail

Nominal size mm

+ Tol - Tol

Pass Fail

Nominal size

+ Tol - Tol

Pass Fail

Pass FailBearing Shoulder run-out

Journal Measurements - NDE

Nominal

Up Tol

Lo Tol

Journal Measurements - DE

mm

mm


Bearing Bearing

Fit Fit

8 Point Measurements 8 Point Measurements

8 Point Measurements 8 Point Measurements

Housing Measurements - NDE Housing Measurements - DE

Pass FailBearing Shoulder run-out

Rotor Balance Data

Balance grade G1.0 G2.5

Plane

NDE

DE

Permitted (g) Actual (g) Position (Deg)

Foot Flatness

Motor viewed from above

Comments

Balance grade to ISO 1940/1 : 2003 Part 1

80

6.19

6.19

80.015

80.011

80.012

80.012

80.011

80.013

80.013

1.82

4.82

333

019

80.002

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

Pulley, bore and keyway in good condition.

80.013

80.005

80.005

80.005

80.005

80.005

80.005

80.005

80.005

80

80.015

80.00275.015

19.98

0.02

170.020

170.020

170.020

170.020

170.020

170.020

170.020

170.020

170

170.026 169.986

170.010

170.011

170.011

170.010

170.010

170.011

170.011

170.010

170

170.026 169.986

80.013

6316 NU316

h7 h7

Electrical Data - Static Test

U1 - V1 U1 - W1 V1 - W1

1 min 10 min PI

uA

Phase to Phase Resistance

Polarisation Index (PI)

Earth Leakage Test (HI-POT)


Insulation Resistance (IR) V@

V@

Baker Surge Test V@

Electrical Data - Run TestNo load test

VTest Voltage

HzTest Frequency

Star

DeltaMotor

Connection

rpmMotor Speed

ACurrent L1

ACurrent L2

ACurrent L3

VTest Voltage

HzTest Frequency

Star

DeltaMotor

Connection

rpmMotor Speed

ACurrent L1

ACurrent L2

ACurrent L3

Load test

KwMeasured Output Power

Bearing Spike Energy Reading gSE

Plateau Temperature Deg C

Vertical mm/s

Horizontal mm/s

Axial mm/s

Bearing Spike Energy Reading gSE

Plateau Temperature Deg C

Vertical mm/s

Horizontal mm/s

Axial mm/s

Broadband Vibration Data

NDE DE

Mechanical Data

Bearing Spike Energy Readings (gSE)

> 0.1 = New bearing0.1 - 0.5 = OK 0.5 - 0.6 = Alarm < 0.6 = Danger

Vibration Data ISO 10816-3For Class II Machines

> 2.80 = satisfactory> 1.80 = good

3396 M Ohm 1800

1800

Balanced both windings 1800

415

50

1483

0.18 0.18 0.18

N/A N/A N/A

40.0

38.0

38.5

0.533

0.002

37.4

0.8

1.1

1.4

0.003

42.1

0.8

1.2

1.62


Photo Description

Photo Description

Photo Description

Further Analysis / Information

Flats on rollers

The outer race of the bearing shows a pattern not unlikeelectrical discharge damage on a bearing. In this case itis our opinion that these marks have been caused by the rolling elements skidding and jamming on the raceway, further marking around the raceway shows traditional smearing marking that is usually associated with rolling elements slipping on the raceway.(see below)

Outer raceway NU316ECP Marking on raceway

Smearing marking on the outer raceway of the bearing.

Outer raceway NU316ECP Marking on raceway

The rolling elements of the drive end bearing show flats evident, this can be caused when the rolling elements skid on the raceways. This can be seen in the middle of the roller on the photograph.

Rolling element NU316ECP

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