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04.06.2018 [ [more] ]

New Factory in SarstedtIn addition to the existing plant, a new state-of-the-art manufacturing facility is under construction at the HELMKE site in Sarstedt (near Hannover, Germany).[ [more] ]

Drive systems - engineered by HELMKEHELMKE is a worldwide acknowledged competence for the delivery of complete drive systems. The converter cabinets engineered by HELMKE are projected and manufactured for customized and branch-specific applications.[ [more] ]

Damage at a high-voltage Cement Mill Drive, 2,500 kW, 5.3 kV, 495 rpm

One of our standing customers in Scandinavia had to experience a great winding damage of the drive motor mentioned above. As consequence of that failure each day several thousand tons of cement could not be produced.
After thorough examinations of the motor it was obvious that the repair works would take quite a few months. Because of comprehensive investigations J. Helmke & Co, Hannover succeeded on the market to purchase a machine of identical construction with high wear which we could repair for quick operation.
For example, we carefully cleaned the winding elements to examine the quality. The evaluation of the quality was done on the basis of tan-D, partial discharge and polarization index measurements.
The mechanical components were thoroughly examined, too and among other things the shaft assembly was examined by means of ultrasonic test and magnetic crack detection. In addition to that, we had to determine extensive damages on the machine housing and we had to examine the possibility to copy several missing housing parts.
After a 4 weeks handling time for comprehensive reconditioning works of the motor components and final successful inspection and testing the motor left our repair workshop to be assembled in the cement factory.

  • After a long-lasting storage the motor arrived at our works with partly damaged and missing housing components.

  • Machining of bearing seats and slip rings in a horizontal turning lathe for piece weights up to 6 t.

  • Slipring rotor ready-for-assembly.

  • Motor components sandblasted and primed. The picture shows base frame, pedestal bearing as well as stator laminated core with winding being ready for assembly.

  • Preparation of assembly of the motor components.

  • Totally revised brush-rocker with renewed insulating parts. Slipring equipment assembled. Clearly visible are the grooved slip rings as well as the brush holders operating at high vibrations and permanent pressure.

  • Motor being partly disassembled but with assembled housing and air guide elements.

  • Assembled pedestal bearing and PT100 temperature measurement sensor.

  • After the final inspection the cement mill drive was provided with a transport safety device and is now ready for operation.
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