Experimental analysis of a prototype voltage stabilizer using an optoelectronic proximity voltage relay

This article discusses the issues of experimental analysis of power quality indicators when using a voltage stabilizer using an optoelectronic proximity voltage relay. Where, the booster voltage stabilizer, the magnetizing windings of which are switched using non-contact voltage relays made on the basis of semiconductor devices, as well as the duration of the transient process when switching active and active-inductive loads connected to the output of the stabilizer. In addition, the article provides information regarding the performance of the developed prototype voltage stabilizer using an optoelectronic contactless voltage relay and verification of an experimental study of the operation of installations with their use. Also presented is material on the experimental study of a prototype voltage stabilizer using an optoelectronic contactless voltage relay in various operating modes. Summarizing the results of experimental studies of a prototype voltage stabilizer using an optoelectronic contactless voltage relay, it can be stated that it fully meets the requirements for such devices and can ensure reliable operation of the power supply network of household electrical consumers.

Analysis and study of energy efficiency by the operation of a voltage stabilizer

This article discusses the analysis and study of the energy efficiency of the operation of a voltage stabilizer using a non-contact voltage relay. In addition, the calculation of the energy efficiency from the use of the stabilizer is presented on the example of the enterprise of the Baysun district power supply of the Surkhandarya region. Summarizing the results of the analyzed and investigated energy efficiency of the prototype of the stabilizer, it can be stated that it fully meets the requirements for such devices and can ensure reliable operation of the power supply network of household electrical receivers with a voltage of 0.4 kV.

Evaluation of Tribological Properties of Bearing Materials for Marine Diesel Engines Utilising the Contact Voltage Method

The contact voltage (CV) method, which can detect miniature failures, has been tested under laboratory conditions to monitor the condition of bearings. In this study, the bearing materials for marine diesel engines, aluminium and copper alloy, were tested on a bearing fatigue wear test bench in the boundary lubrication state, which was found through tests of the different parameters. The frictional torque, the oil film thickness and the bearing temperature were measured, as well as the CV signals. The possibility of using the CV technique to monitor the condition of the bearings was also assessed by evaluating the tribological properties. After 10 h of the test, the aluminium alloy bearing was worn to the alloy layer. Then, the wear-reducing layer on the surface of the bearing slowly peeled off, and the wear was intensified. Due to its higher wear-resisting property, the amount of wear on the copper alloy bearing increased slowly. After 20 h of the fatigue wear test, the aluminium alloy bearing became severely worn, the CV characteristic was up to 81% of the initial value, the bearing temperature increased by 6.3%, and the torque value increased by 32%. This indicates that the CV method is more sensitive to wear failure. Due to better wear resistance, the copper alloy bearing showed only slightly wear and a small increase in its CV value. The main contribution is that the CV method is useful for monitoring the lubricated condition and for evaluating the tribological properties of bearings. This research has laid technical foundations for the engineering of the sliding bearing wear monitoring system based on the CV method.

Friction Forces in a Linear-Guideway Type Recirculating Ball Bearing Under Grease Lubrication

This paper deals with friction forces in a linear-guideway type recirculating ball bearing (linear bearing) under grease lubrication. During the experiments, the friction force, temperature, and electric contact voltage of a grease lubricated linear bearing (test bearing) without seals were measured. Experimental results showed that the measured friction forces of the test bearing were fluctuated with the ball passage period. The measured time-average friction force FAVG (measured FAVG) was nearly constant when the grease filling rate x (=grease filling volume/internal space of the bearing) ≥0.13, while the measured FAVG decreased as x decreased when x < 0.13. In addition, the measured temperatures were almost constant, and the measured contact voltages indicated that the contacts of the balls and raceways were electrically insulated by the grease film. Next, the expressions of friction forces due to differential slip (FD), elastic hysteresis loss (FE), and rolling traction (FRT) were shown. The calculated FD + FE + FRT for the test bearing was almost equal to the measured FAVG around the grease filling rate of x = 0, while in cases where x > 0, the measured FAVG was greater than the calculated FD + FE + FRT. This means that when x > 0, an agitating resistance (FA) from the grease might cause the measured FAVG to be greater than the calculated FD + FE + FRT. Finally, an expression for the friction force of a linear bearing, FAVG = FD + FE + FRT + FA (which can estimate the measured ones) is proposed.

Safety analysis of live working operators under zero potential

With the application of the live working method of the zero phase potential of the working phase more and more widely, the safety of the live working operators is urgently needed for research. Considering the influence of electric shock time and frequency on the allowable current of the human body, the safe current is analyzed during live operation, and it is concluded that in the frequency range of 50~60Hz, the current below 50mA can basically guarantee that it will not die after electric shock. In the three scenarios where the insulator maintenance personnel accidentally touch the ground, the grounding wire shocks the electric shock and the charged electric shock of the tower, the human body electric shock is further analyzed. Finally, based on the CDEGS, the model of the human body contacting the grounding conductor is established. The simulation verifies the influence of the allowable current on the time and frequency of the human body withstand current under the zero potential state through the contact voltage diagram and the danger degree diagram.

Development of contactless solid state voltage relay

The article deals with the research issues of compact, reliable, high-speed semiconductor solid-state non-contact voltage relays with an increased service life, combining a sensitive system and a powerful actuator with a sinusoidal voltage curve at the load. Theoretical studies of a controlled resistive and non-autonomous dynamic circuit, consisting of a thyristor connected in series with a parallel circuit containing a capacitance and an active resistance, under the influence of an external sinusoidal voltage, which can be used in control circuits of power thyristors, are presented. An experimental characteristic is shown with a description of the operating principle of the developed solid-state non-contact voltage relay.

Optimal management strength of cutting parts of tools from STM when there is turning heatresistant alloys on CNC machines

The article considers the developed and implemented in the cutting process methodology for managing the dynamic strength of the cutting parts with the tops of tools from STM simultaneously on the front and back surfaces of these tools at thin turning of heatresistant alloys on CNC machines. The specified methodology is based on optimizing (physical, thermal) models of process of thin turning of heatresistant alloys tools from STM developed by us and the offered concept of passing of process of interaction of the processed and tool materials in the conditions of optimization of contact voltage and temperatures at the same time on the front and back surfaces of the tool from STM when cutting.