testing and commissioning procedure for motors
TRANSCRIPT
Energy & Power For All !
Home
Technical Articles
Subscribe to articles
Subscribe to downloads
Categories
Electrica l Spreadsheets
Engineering Guides
EE General guides
Power Substations
Schneider Electric CTs
Siemens Basics of EE
Automation and Control
Alternative Energy
EE Resources
EE Video Course
PLC Programming Course
Testing and Commiss.
Network Theorems
Contact
Testing and Commissioning Procedure For
Motors
Testing and Commissioning Procedure For Motors // Photo by TECO Middle East (TME)
Scope Of Motor Testing
It should be noted that the scope of motor test ing depends upon the motor type and size, this
being indicated on the inspection forms.
Motor vibration shall be measured in a tri-axial direction, i.e.:
Point x axis – side of bearing housing at shaft height
Point y axis – top of bearing housing
Point z axis – axial of bearing housing at shaft height
The measurements shal l be carried out with an instrument conforming to ISO 2954 (10-1000
Hz f requency range). With the motor at normal operating temperature, the vibration velocity shal l not
exceed 2.8 mm/s RMS, or 4 mm/s PEAK, in any direction.
For bearings fitted with proximity probes, the unfiltered peak-to-peak value of v ibration
(including shaft ‘run-out‘) at any load between no load and full load, shal l not exceed the following
values:
50 µm for two-pole motors
60 µm for four-pole motors
75 µm for six-pole or higher motors
Motor bearing (photo by CCLW INTERNATIONAL)
Bearing temperature r ise limits following a ‘heat run’ of 3.5 – 4 hours are as follows:
Rolling bearings:
Outer ring measurement max. 90 °C
Temperature rise from ambient max. 50 °C
Sleeve bearings:
Oil temperature max. 90 °C
Bearing temperature rise by RTD max. 50
°C
Lub. oil temperature rise from ambient
max. 30 °C (for forced lub. o il sys tems ).
When commissioning or re-commissioning
motors, precautions shall be taken to
avoid excessive vibration caused by the
phenomenon known as ‘soft foot‘; i.e.
feet which do not have solid flat contact
with the base prior to the tightening of
the holding-down bolts.
This may be measured and rectified
during insta llat ion or detected during running by the loosening of each holding-down bolt in turn
while measuring motor vibration.
Motor ‘Soft Foot’ Condition
‘Soft feet’ are those which do not have solid flat contact with the base prior to the tightening
of the holding-down bolts; one or more feet may be ‘soft ’ as shown in Figures 1 to 3.
The profile of the foot contact area may be as shown in Figures 4 to 6 .
The profile of the foot contact area (Figures 1, 2 and 3)
Figure 1 - Machine resting on 3 feet, foot 4 is raised or ‘soft’
Figure 2 - Machine resting on diagonal formed by feet 3 and 4, feet 1 and 4 are ‘soft’
Figure 3 - Bottoms of al l 4 feet are not para llel with base, feet 3 and 4 are ‘soft ’
Profile of 'soft foot' contact area
NOTE: Re-
machining of
rotor feet is
required in
Figures 4 and
5; temporary
use of wedge-shaped shims may be acceptable (maintenance).
Forms
Form 14 – Inspection of electric motor – Cage-induction type (incl. control unit)
Inspection of electric motor cage-induction type (including control unit)
Form 4 – Inspection of Switching Units – HV Switchgear
Inspection of Switching Units - HV Switchgear
Form 11 – Inspection Of Outgoing Unit – LV Switchboard
Inspection Of Outgoing Unit - LV Switchboard
Reference: Field Commissioning and Maintenance Of Electrica l Installa tions and Equipment Manual
Recommended EE articles
Edvard - Electrica l engineer, programmer and founder of EEP. Highly special ized for design of
LV high power busbar trunking (<6300A) in power substations, buildings and industry fascil ities.
Designing of LV/MV switchgears. Professional in AutoCAD programming and web-design. Present
on Google+.
© 2014 EEP - Electrica l Engineering Porta l. All Rights Reserved | Privacy Policy | 44 queries in
0.373 seconds.
Powered by CsanyiGroup
