Articles

For years parts have been inspected via Magnetic Particle Inspection and then placed back into operation, with sometimes a small residual or worse yet, a strong magnetic field. When residual fields are combined during unit assembly they can interact and be the origin of stray shaft currents. MPS experts, after years of engineering investigations, see that […]

Principles of Magnetism and Stray Currents in Rotating Machinery By Paul I. Nippes P.E. President of Magnetic Products and Services Inc. Introduction This paper presents a collection of information that should be useful for understanding magnetism in machinery. It can also be used as a reference guide for engineers and technicians regarding the principles of

MPS VCM-E’s connect and operate with any manufacturers grounding or voltage sensing devices. Shaft Grounding Devices need to be insulated to capture all stray shaft grounding current and monitor properly. Shaft Voltage Sensing Devices should not be grounded. Raw Signals are consolidated and conditioned by VCM-E’s into three meaningful values. These values include: Peak Current, Peak Voltage, and Average

Below is a downloadable article on “Understanding Shaft Voltage and Grounding Current of Turbine Generators” by Paul I. Nippes, PE and Elizabeth S. Galano. Abstract Attendant with the current practices of extending periods between turbine-generator planned outages is the need for improved and careful condition monitoring. By determining the condition of the turbine generator units

Examples of Shaft Grounding Devices Available* It is advisable that grounding devices designed specifically for shaft grounding duty are chosen. Grounding devices vary in performance and application. MPS encourages the end user to contact suppliers and determine which design best suits their application. Regardless of the device selected, all devices require a certain amount of

SHAFT CURRENT DAMAGE: TYPES 1. Frosting By far the most common type of shaft current damage. Parts affected are bearings, seals, thrust collars, journals, and to a lesser extent, gears. The appears is that of a sand blasted surface, characterized by over­lapping, molten, shiny pit marks. If the entire available surface is affected, the damage