Will diesel generator sets generate shaft voltage?

Recently, some customers have become interested in the shaft voltage of diesel generator sets. In this regard, Haixing will give you a comprehensive introduction to what shaft voltage is and why the generator set produces shaft voltage, thereby deepening your understanding of the generator set .

The shaft voltage refers to the voltage generated between the two bearing ends of the motor or between the motor shaft and the bearing when the generator is running. The generator shaft voltage always exists, but is generally not high. However, when the insulation pad loses its effect due to oil stains, damage or aging, the shaft voltage is sufficient to break through the oil film between the shaft and the bearing and discharge occurs. Over time, the lubricating and cooling oil will gradually deteriorate. In severe cases, the rotating shaft and bearing shells will burn out, causing shutdown.

Why does the generator set generate shaft voltage? This is due to the imbalance of the stator magnetic field of the generator, and an induced potential is generated on the generator's rotation axis. The reason for magnetic field imbalance is generally caused by the large local magnetic resistance of the stator core (such as rust of the stator core), and the uneven air gap between the stator and rotor.

In order to prevent damage caused by shaft voltage, Haixing recommends that polyester glass stacks can be used to make an insulating plate at the bearing ring at the excitation end and the oil sealing device used to prevent hydrogen leakage. The insulating plate has an insulation resistance measurement lead-out machine. When installing and operating the generator set, the voltage between the shaft and bearings of the generator set should also be measured and checked to ensure that it is within the normal range and does not affect the operation of the unit.