monitornawer.blogg.se - Electric motor rewinding equipment

#ELECTRIC MOTOR REWINDING EQUIPMENT FULL#
#ELECTRIC MOTOR REWINDING EQUIPMENT VERIFICATION#

Said specification is available from the U.S. Motor repair specification for a low voltage induction motor (reference – DOE/BP-2748). You will also notice the quality of the laminations as compared to 1a. This is good as it forms the coils into a firm mass. The 1b stator utilizes larger binding material in addition, notice the resin deposition between the wires. In image 1a, notice the small diameter binding as well as the quality (lack thereof) of the laminations. See Figure 1a & 1b Above. Figures 1a and 1b depict stator construction from two different motor manufacturers. Therefore, to ensure a quality product, every motor re-wind requires a clearly defined specification written specifically for that motor.

If this data doesn’t convince you of the importance of a well-executed vendor qualification process, vendor audit, and repair specification, perhaps this will:įACT: No two motors (OEM’s) are built the same.

All the large repair shops, 66% of the medium shops, and up to 20% of the small shops had vibration testers, DC High Potential testers, and surge comparison testers.

Up to 80% of the large repair shops, up to 40% of medium shops, and under 15% of the small shops had specialty equipment, including dynamometers, core loss testers, three phase watt-meters and acoustic testers *some of the dynamometers were homemade test beds or used a shaft connected to a brake.

85% of the repair shops had meg-ohm meters, low resistance ohm meters, and AC high potential testers.

#ELECTRIC MOTOR REWINDING EQUIPMENT FULL#

Only the largest repair shops had a full complement of test equipment for detailed analysis, including before and after testing.49% of shops perform a no-load test prior to performing repair and rely upon the tests performed to determine the motor condition.Most of the repair shops viewed resistance testing as a method to evaluate DC electric motor fields only.

Only 1.5% of surveyed repair shops used any form of quality assurance testing.

Of the repair shops that used quality assurance procedures, 40% were repair procedure specifications, 25% were test specifications, and 21% were EASA standards.

Only 33% of repair shops used written quality standards and were familiar with any type of quality assurance procedures.

Although insulation, winding resistance, vibration, phase balance (surge or MCA) and core loss testing should be done routinely as part of a quality repair, only insulation testing was performed routinely.

Only 4% modify windings for reliability or energy improvements.

81% of repair shops reported that they modify windings because of equipment limitations or shop preference.

The following data was compiled from a study titled, Motor Diagnostics and Motor Health Study “Industrial Motor Repair in the United States”. This leaves either the motor owner to perform ‘before’ and ‘after’ tests, the motor owner to provide test requirement specifications, or a combination of both – in which the owner performs a commissioning test upon receipt of the motor from the repair shop in an effort to Trust, but Verify.

#ELECTRIC MOTOR REWINDING EQUIPMENT VERIFICATION#

In each case, the motor will be different from the original capability and reliability of the motor and it’s original design.įew electric motor repair shops perform ‘before’ and ‘after’ verification tests of the winding to determine if changes have occurred. Winding configuration changes may modify the electric motor’s impedance balance or change the motor’s output torque. Wire size changes will modify the motor’s I squared R losses. Many motor repair shops will adjust the original winding design, including reducing wire size or the configuration, for convenience or ease of winding. In Part 2, we will discuss why it is so important to develop and agree to a motor repair specification. In Part 1, we discussed repair vs replace and the vendor selection process.