{"id":13674,"date":"2023-12-27T17:31:46","date_gmt":"2023-12-27T16:31:46","guid":{"rendered":"https:\/\/eneria.pl\/blog\/serwisowanie-gazowych-agregatow-kogeneracyjnych-pradnice-w-roli-glownej\/"},"modified":"2026-02-03T10:48:54","modified_gmt":"2026-02-03T09:48:54","slug":"serwisowanie-gazowych-agregatow-kogeneracyjnych-pradnice-w-roli-glownej","status":"publish","type":"post","link":"https:\/\/eneria.pl\/en\/blog\/serwisowanie-gazowych-agregatow-kogeneracyjnych-pradnice-w-roli-glownej\/","title":{"rendered":"Servicing of gas-fired cogeneration units: generators play the main role"},"content":{"rendered":"

During the operation of any device, wear and tear occurs. This is particularly evident in the operation of mechanical equipment, where interlocking parts or components work together. Despite efforts to eliminate friction or reduce it as much as possible with lubrication or systems equipped with rolling bearings, the process of wear during operation is unavoidable. Based on the operating instructions for a given equipment, within a specific time frame, it is essential to conduct the following: service inspection, overhaul or rebuild. While everyone agrees on the need to perform mechanical inspections on the gas engines of CHP units, hardly anyone remembers to inspect the dynamo.<\/p>\n

\"\"Image 1. Dynamo rotor.<\/em><\/p>\n

The dynamo plays a very important role in a CHP unit, as it converts the mechanical energy from the engine into electrical energy. Apart from lubricating the dynamo’s bearings, which is evidently written on its nameplate (we can read from it how many operating hours the bearings should be lubricated and how much grease should be used), no one pays much attention to servicing the dynamos. More foresighted people measure the resistance of the dynamo’s stator winding. If for some reason the generator is out of service, the prevailing belief is that nothing should be done with the dynamo because it is not actively working, so such an inspection is not required. And yet, even though in theory the dynamo is not actively working, a lot could happen to it. Namely, during the shutdown, the insulation can become damp and its insulation resistance can decrease, which may lead to an electrical breakdown, resulting in the burning of the dynamo’s circuits. To avoid this, it is absolutely necessary to check (measure the resistance) the insulation of the dynamo after a shutdown. Another phenomenon we may encounter when starting the dynamo after a shutdown is the excessively loud operation of the bearings. This can be caused by the bearing balls impressing the bearing races as a result of prolonged pressure of the balls in “one” location. This, of course, applies to dynamos with rolling bearings.<\/p>\n

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Image 2 Dynamo’s stator.<\/em><\/p><\/div>\n

Dynamos in power generators are most often selected in such a way that their overhaul is performed together with the overhaul of the engine. There is an economic and practical justification for this. For main services, the engine must be removed from the frame and overhauled at the generator manufacturer’s factory service. It is most convenient to remove the engine from the workplace together with the frame on which it is mounted along with the dynamo. In this case, after dismantling the unit once, we have access to the engine and dynamo, and after removing the dynamo from the frame, all that remains is to perform an inspection at a specialised facility.<\/p>\n

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Image 3 Damage to the engine varistor and damage to the diode bridge varistor.<\/em><\/p>\n

The activities performed during the dynamo service include:<\/p>\n