KEEPING way ELECTRIC MOTORS EFISIENCY when repair

The challenge for all electric motor rewinding workshop al:
• Doing the best job possible
• Shows the contumer that all inspection and testing is performed and documented that the rewinding work does not result in the decrease of the efficiency of the motor.
If the efficiency decreases, meaning the motor needs to be greater power than ever before, adding to the waste of electricity usage.
From the observation happens that almost all of the motor after rewinding, efficiency becomes down. Study concluded that the influence of al: burning core, winding design, bearing type, air gap and winding resistance.
To maintain the efficiency of EATA make the "recommended practice", which contains
What to do and what not to do, when you do rewinding:
Work.
1 Make the "quality assurance program"
2 Perform program test / calibration of all measuring instruments and test equipment.
3 Perform test stator core before and after unpacking.
4 Repair or replace the damaged laminate.
5. Evaluation of impact efficiency when changing the winding design
6 Measure and record the resistance / temperature resistance winding and space
7 Measure and record amperage and voltage during the test.
Do not
1 Do not overheat the stator core
2 Do not use the fire when unpacking
3 Do not sandblast iron core mem-
4 Do not "short" laminate, by grinding or clicking miser (filling)
5. Do not enlarge the airgap
6 Do not add to the resistance of the stator winding.
7 Do not knurl, peen, paint bearing fits
8 Do not modify the prior approval of the owner.
Further discussion as follows:
DO
1 Quality assurance program:
Make sure that the workshops do what we want. Wire size, the size of the lead wire, insulation material is according to spec. Test quality of varnish varnish according to the manufacturer's recommendations, all must be documented when dismantling, testing, inspection, etc..
2 Perform program test / calibration of all measuring instruments and test equipment.
All test equipment, measuring and testing must be calibrated regularly by air treatment or certified, at least once a year.
3 Perform test stator core before and after unpacking.
Document the stator core test, to ensure that no damage when demolition winding cores. EATA provides guidance test the cores with a single phase Wattmeter.
4 Repair or replace the damaged laminate.
Separate laminates are already short. When the core restacking wear coreplate already in varnish next. The drying process must follow procedures when varnishing curing. Stackinglah on the side that is not in the varnish, varnishing leads the side.
5. Evaluation of impact efficiency when changing the winding design
Must take into account that changes in winding wire can also cause changes in the efficiency and performance possible. Changing the number of winding cross-section and length can change the total winding resistance.
6 Measure and record the resistance / temperature resistance winding and space.
Measure and document the winding resistance and temeprature space. Because temperature affects the price of resistance
7 Measure and record amperage and voltage for the final test
During the final test subject must be monitored and recorded, from the start, per ½ hour or a certain time period: room temperature, bearing temperature, winding temperature, vibration, starting current, the ampere all phases, all the phase voltages. Ampere large suit of the load, the higher voltage causes ampre larger no-load, voltage does not cause the current balance does not balance and greater.
DON "T / Never
1 Do not overheat the stator core
Dismantling by burning, very detrimental. This will result in core-plating damage, which resulted in the emergence of short-plating on laminated cores. Short on laminated cores -looses cause large. EATA provide guidance, heating should not be more than 360 C.
2 Do not use the fire when unpacking
Dismantling the fire is strictly prohibited, and his deep flame temperature can not be controlled
3 Do not sandblast iron core mem-
Laminated cores if disandblast also lead to short, thereby increasing the core-looses.
4 Do not "short" laminate, by grinding or clicking miser (filling)
Do not filing or grinding, as it will cause a short between the laminate. If cleaning the varnish on the hole in the stator, do not enlarge the hole, because it will cause a short between cores.
5. Do not enlarge the airgap
Enlarge the stator bore or cut / reduce the diameter of the rotor causes the water-gap getting bigger. Which led to large increases magnitasi flow, resulting in large increases losses
6 Do not add to the resistance of the stator winding.
Measure the diameter of the wire carefully, after peeling varnish coating, the total cross-section should not be reduced, also the number of windings. Changes in cross-section and the number of windings affect winding resistance changes, then change the motor performance.
7 Do not damage, paint bearing fits
Do not do anything that damages the bearing fits, this can lead to bearing damage early or premature.
8 Do not modify the prior approval of the owner.
Making changes or modifications could result in changes in performance. Changes in temperature cause changes in the motor fan. Bearing and seal change causes changes in friction, which affects the efficiency.
conclusion
Rewinding or repair jobs should not give rise to a decrease in efficiency, at least be fairly constant. Effiensi down means requires electrical energy, which means more waste.
Suppose the initial motor efficiency 87% and 84% efficiency after direwinding.
With the formula approach, the consumption of electrical energy into: 87/84 x X = 1.04 X
If X eg 300 Kw, then X = 312 Kw 1:04
Per day komsusi before rewinding = 24Hx 300 Kw = 7200 KWH
Per day consumption after rewinding = 24H x 312Kw = 7488 KWH
The difference is significant at 288 KWH per day.