Features of technical operation of voltage regulators on electric locomotives VL80S and VL80T
Experience of the North Caucasus branch
B.I. PAVLITSKY, Ph.D. technologist, science, head of the quality management group of LocoTech-Service LLC,
K.A. NIKITIN, Deputy Head of the Krasnodar Locomotive Service Depot
At the South-Western range, which includes the South-Eastern, Volga and North Caucasus roads, the main traction rolling stock providing freight transportation are electric locomotives VL80S and VL80T. The inventory park of the North Caucasus Traction Directorate contains about 800 sections of these electric locomotives.
It should be noted that in this article we are talking about VL80T electric locomotives of fairly late production, the so-called “large numbers” - “b/n”. The fact is that electric locomotives VL80T of early production (“small numbers”), like electric locomotives VL80K, are currently not serviced by the North Caucasian branch of LocoTech-Service LLC. Also, the North Caucasian branch practically does not service VL80R electric locomotives, however, these electric locomotives are accepted for service by LocoTech-Service LLC, so the article’s materials can be useful for a very wide range of drivers and repairmen who, when carrying out both technical and production operations often face similar problems.
Over the past three years, at the South-Western test site, there has been a tendency of non-compliance with the standard for maintaining the operating fleet of AC freight electric locomotives. One of the main reasons for unscheduled repairs and failures of technical equipment of the 1st, 2nd categories (OTS of the 1st, 2nd categories) for the electric locomotives discussed in the article is a malfunction of the voltage regulator type RN-43 (RN-4).
The voltage regulator type RN-43 (RN-4) is the main part of the static charging unit and is designed to maintain the voltage of control circuits within 47.5 ... 52.5 V (Fig. 1.2).
A malfunction of this node leads to the following consequences:
- desynchronization of the main controller shafts - on the considered electric locomotives VL80T (b/n) and electric locomotives VL80S these are controllers of the EKG-8Zh type;
- violation of safety devices;
- false operation of the grounding relay (according to diagram No. 88);
- failure of a transformer controlled by magnetization shunt (TRPS);
- failure of electric locomotive batteries.
If we look at the statistics of locomotive calls for unscheduled repairs, the following picture emerges. In 2021, 265 unscheduled repairs were recorded due to a malfunction of the voltage regulator type RN-43 (RN-4), which amounted to 10% of the total number of unscheduled repairs on electrical equipment (2661 cases). For 2022 - 389 unscheduled repairs, which amounted to 19% of the total number of unscheduled repairs on electrical equipment (7249 cases).
Statistics of failures of technical equipment indicate that during the period of 2021, failures of the 1st and 2nd categories were recorded - 81 cases, for 2022 - 96 cases.
When calculating the financial costs of restoring the functionality of a voltage regulator type RN-43 (RN-4), from 650 thousand to 1 million rubles are spent per year, and fines for failures of technical equipment of the 1st and 2nd categories range from 240 thousand up to 300 thousand rubles.
The presented quantitative data indicate the very significant weight of the problem under consideration.
A significant part of such failures occurs due to improper production operation (intended use) of electric locomotives or after carrying out technical operation activities, mainly at PTOL, in the scope of TO-2.
The root cause of the malfunction of the RN-43 voltage regulator is unauthorized intervention in the adjustment of a wirewound resistor of the PEV-50-200 type by personnel. As a result, the movable clamping clamp breaks along the body and the side part of the resistor body, cleared of the protective coating, is destroyed.
The main reason for the malfunction of the RN-4 voltage regulator is unauthorized personnel intervention in adjusting the PPB-25E 100 Ohm 5% resistor, the consequences of which are:
- failure of the capacitor (according to scheme No. C6,7, 8, 9,10,11,13);
- failure of the transformer (according to scheme No. T1, T2);
- failure of the zener diode (according to scheme No. V16, V20);
- failure of the diode bridge (according to diagram No. V23-V26).
Taking into account the shortage of freight electric locomotives VL80S and VL80T in the operating fleet of the South-Western range, compliance with the requirements of the repair manuals and the implementation of the measures being developed do not make a tangible contribution to solving the above problem. One of the solutions to the problem of eliminating the causes of malfunctions and restoring the standard performance of the RN-43 (RN-4) regulator is to modernize the design, namely, to exclude unauthorized access to the regulator.
In accordance with the design documentation, voltage regulators of the RN-43 and RN-4 types were installed on the VL80S electric locomotives by the manufacturer. The voltage regulator type RN-43 (drawing 6TN.238.043) is located on the distribution board of type RShch-34 and was installed on electric locomotives VL80T (b/n) and VL80S up to No. 2174.
Electric locomotives VL80S No. 2174 and higher began to be equipped with a voltage regulator of the RN-4 type (drawing 6TS.238.004), which was provided for by the design of electric locomotives VL85. This regulator is located on the ShchR-1 type distribution board. This change in the voltage regulator affected a number of design improvements: instead of the TPSH transformer, a Tr-214 type transformer was installed (according to scheme No. 48); instead of contactor “K” a contactor is installed (according to diagram No. 162). Despite all the design changes, voltage regulators of the RN-43 and RN-4 types are still structurally located in the public domain.
One of the effective ways to prevent unauthorized access to this unit is to transfer the voltage regulator type RN-43 (RN-4) to the high-voltage chamber (HVC) in the area of the fan motor No. 1 (Fig. 3, 4). The peculiarity of this technical solution is the simplicity of its implementation, namely:
- possibility of performing any type of maintenance and current repair of an electric locomotive;
- lack of need for highly qualified specialists;
- no need to purchase additional equipment and specialized tools;
- relatively small material and labor costs for modernization.
According to preliminary calculations, the cost of modernization to transfer a voltage regulator of type RN-43 (RN-4) to a high-voltage chamber will be about 700 rubles. Taking into account the fact that the inventory fleet of the North Caucasus Traction Directorate includes about 400 units of the above series of locomotives, the cost of modernizing the entire fleet will be about 280 thousand rubles. As a result, the payback period for the modernization of electric locomotives VL80S and VL80T (b/n) registered with the North Caucasus Traction Directorate will be from 3 to 5 months.
It is also worth noting the experience of operating AC passenger electric locomotives of the EP1 series of all indexes operated with the participation of LocoTech-Service LLC. On these locomotives, the RN-6 type voltage regulator, according to the design documentation, is located in the power cabinet (ShP-21), which, in turn, acts as a high-voltage chamber. Such design solutions provide the following result: since 2007, electric locomotives EP1M and EP1P registered at the Kavkazskaya operational locomotive depot of the North Caucasus Traction Directorate have had no OTS of the 1st, 2nd categories and unscheduled repairs due to a malfunction of the voltage regulator type PH-6.
