Electrical workshop was designed and built as part of the Atyrau Training Centre. SP-1 and SP-3 trainees had their practical training in this workshop (there were no electrical trainees in SP-2). Some of the SP-3 trainees are now working in France, some in Karabatan, others on D Island. The main purpose of this workshop is to train people who have, perhaps, little or no practical experience and teach them to "work with hands”.

Trainees get a chance to build an experience of working with different equipment. They are given different projects which they should do by themselves. This means that trainees have to solve a given problem: research it, come up with the solution, design, implement and then test it.

For example, trainees are given a project to build a system for driving one of the motors in the workshop according to given drawings. They then have to built and test it, program a PLC and so on. So by the time they finish their practical training they should be confident of using tools, simple test equipment. Afterwards trainees can develop their skills on field.

SP-3 trainees working on the practical project.

Another project which was carried out by one of the SP-3 trainees touches current safety problem. A trainee was given a bench grinder. The problem with that is when you start it and then stop it by disconnecting the supply because of the inertia of the grinding wheel it can take a long time to stop. 

With a big machine it can take many minutes, 5-10 or more, to stop. All the time dangerous rotating parts can possibly cause injuries to personnel. There is a regulation governing this kind of equipment which tells that if you have dangerous moving parts it should stop in reasonable time, usually defined to be about 10 seconds. So the task was given to a trainee - stop a bench grinder in 10 seconds using electromagnetic means. Possible methods of solving the problem were given to a trainee. He chose the method of DC injection breaking. The principle of it is that when the stop button is pushed a 3-phase AC supply is replaced with a DC supply and the rotor of the motor stops. The 3-phase AC supply produces rotating magnetic field which drags a motor. When the stop button is pushed the contactor disconnects the 3-phase AC supply, the DC supply is connected from the transformer to the rectifier and fed into the second contactor which now feeds the motor. The rotating magnetic field is replaced then with a fixed magnetic field. The rotor is now spinning through that and breaking forces are generated. By the means of DC injection breaking the bench grinder was stopped in three seconds.

This project was carried out entirely by a trainee. He produced the drawings (he was taught how to use the Acad package): electrical, layout (where to put everything on the panel), wiring diagrams. So that is a standard trainees are supposed to reach.

At the stage of practical training there is different equipment available in the workshop to reinforce basic electrical principles. Though trainees usually study these at college or university before they come here, here we allow them to improve practical knowledge.

At the stage of practical training there is different equipment available in the workshop to reinforce basic electrical principles. Though trainees usually study these at college or university before they come here, here we allow them to improve practical knowledge.

There are AC/DC power supplies, load simulators, a selection of meters for measuring power, voltage, current, digital multimeters, clip meters, digital oscilloscope. By the time they used various exercises they get involved into something a bit more practical, design something, which relates more closely to what they’re going to find on the field.

An overview of equipment available in the workshop.

Megger Automatic Oil Test Set

The Megger OTS AF/2 test sets are used to determine the dielectric strength of insulating oils used in transformers, switchgear and other electrical apparatus. This test offers a quick guide to the general state of the oil and may show if the oil is contaminated by moisture or particles. A low dielectric strength may indicate that the oil is deteriorating and requires replacement.

The standards for sampling techniques and procedures are programmed into the OTS AF/2 series to reduce operator testing time.

These oil tests offer fully automatic operation plus the benefit of a built in printer to produce a hard copy of the test results and the ability to program up to five user defined tests for individual applications. Standard stirring with the OTSAF/2 is achieved by a magnetic stirrer bar. The withstand test can be set to operate at test voltage up to 60 kV and with an initial stand time.

A spark was produced with a breakdown voltage of 57.2 kV.

This article was based on the interview with Bill McLeod, Electrical Training Instructor