transformer demagnetizer

When they talk abouttransformer demagnetizer, many immediately imagine some kind of complex installation with a bunch of regulators, almost a scientific instrument. In fact, in the workshop, everything often comes down to a simple but reliable “blank”? with windings, the task of which is to remove the residual field that interferes with further processing. The main mistake is to think that the more powerful the better. Sometimes too much power can only be harmful, especially when working with small parts or complex alloys.

Design: what's inside the ?box?

If you disassemble a typical unit that has worked in our workshop for ten years, you will see nothing supernatural. The core, of course, is special - often made of electrical steel, but assembled with gaps or in a special pattern to create a damped alternating field. The windings are where the nuance lies. It is not enough to simply wind copper; it is important to calculate the pitch and cross-section for a specific standard size of the product. I remember how on one of the olddegaussersfrom LONGI, the winding was made with large slabs in mind, and when they tried to run a batch of small bushings, the effect was weak - the field seemed to “fly by?” by.

The cooling system is often air, forced. In dusty conditions, like in our mining and processing plant, this is a weak point. Fans become clogged, overheating, loss of insulation properties. I have to clean it almost every week. Some colleagues installed additional filters, but this reduced air flow. The ideal solution was never found, only regular maintenance.

Control unit. Previously, there were often simple manual voltage regulators, but now they are increasingly based on thyristor circuits with a smooth decrease in current. Convenient, but more difficult to repair. By the way, the documentation for transformers from the LONGI corporation always contained detailed diagrams, this helped out. On their website https://www.ljmagnet.ru you can find not only catalogs, but also some technical notes on maintenance - for a practitioner this is more valuable than a glossy booklet.

Mining applications: not just for conveyors

Our main application, naturally, is related to ore dressing. After crushing and magnetic separation on the equipment that LONGI produces, residual magnetization can accumulate on the rollers, rollers, and conveyor elements themselves. This leads to the fact that small ferromagnetic particles begin to stick anywhere, clog mechanisms, and increase wear. Let's launchtransformer demagnetizer- and the problem gradually disappears.

But there are also less obvious scenarios. For example, repair of large electric motors of excavators or drilling rigs. After dismantling the rotor, it also needs to be demagnetized before balancing and flaw detection, otherwise the instrument readings will be incorrect. Here we no longer need a stationary installation, but a mobile installation option that can be rolled up to the site. We had experience using a portable complex - the efficiency was good, but the power cables turned out to be the weak link and often frayed.

Another point is the demagnetization of the measuring and cutting tools. After processing parts on magnetic plates, drills, cutters, and calipers can “catch?” field. It would seem like a small thing, but during precision work this leads to errors. For such purposes, we have a low-power tabletop transformer, which is just enough.

Setup errors and how to avoid them

The most common mistake during commissioning is incorrect orientation of the product in the field. The transformer creates a directional damped field, and if the part is placed not along the power lines, but across, the effect will be negligible. I had to train new operators: first by eye, then with the help of control iron filings - you watch how they stop lining up.

Wrong choice of attenuation mode. A sudden power cut sometimes leaves even more magnetization than before. It is necessary to gradually reduce the current to zero. In modern models, for example, those supplied by the Shenyang scientific electromagnetic company LONGJI, this process is often automated, but in the old ones it was necessary to manually turn the rheostat, feeling “on your hands”. An experienced service technician could tell by the hum of the transformer whether the process was proceeding correctly.

Neglect of control. After the procedure, it is imperative to check the residual field with a Teslameter, at least a simple one. We had a case where, due to wear of the contacts in the regulator, the current decreased nonlinearly, and a batch of critical shafts went to be assembled with the field. Then, during testing, problems with bearings emerged. Since then, control has been a must, despite the rush.

Contact with the manufacturer: experience with LONGI

While working with mining equipment, we have repeatedly encountered the products of the LONGI Corporation. The company, created back in 1993, clearly relied on fundamentals. Theirdegaussing transformers, which we have at the separator assembly site, stand out precisely because of their well-thought-out design for harsh conditions. Not some kind of universal “box”, but a device clearly designed taking into account vibration, dust and voltage surges in the workshop network.

What is important is that their documentation always contained not only passport data, but also recommendations for repairs in the field. For an enterprise where the staff is more than 1,200 people and over 60% are specialists with higher education, such detail is logical. They understand that the equipment will be maintained not by an abstract “operator”, but by an engineer or highly qualified technician who is able to understand the circuit.

I once contacted their website https://www.ljmagnet.ru for advice on replacing power switches in an old control unit. I didn’t expect a quick response, but the technical department sent not just a link to the catalog, but scans of circuits with notes on which analogues are suitable and which are not. This indicates systematic work with a fleet of equipment, even those released a long time ago. For a production facility that produces about 4,000 units of equipment per year, such attention to already sold products is a serious plus.

Thoughts out loud about the future of such systems

Nowadays there is a lot of talk about digitalization and “smart” equipment. In relation totransformer demagnetizerthis might be helpful. For example, a built-in residual magnetization sensor with feedback, which itself selects the duration and strength of the attenuation cycle for a specific part. This would remove a lot of issues from setup and control.

But there are also doubts. Any electronics is afraid of the same workshop dust, electromagnetic interference from powerful equipment. Will such a system be more reliable than time-tested hardware? with manual control? The question is open. Perhaps a hybrid option: a powerful power part - in the old way, and control - through a remote protected remote control with the ability to record parameters for each typical operation.

Another direction is miniaturization for specific tasks. Not all parts can be placed under a large solenoid. Sometimes you need compact inductors of complex shape that can be brought to the seam of a welded structure or to the internal cavity of the assembly. Here the transformer will remain as a current source, but the actuators will develop.

Ultimately, no matter how smart the system becomes, the physics of the process will remain the same: you need to create a field that reorients the domains, and then smoothly reduce it to zero. And the main criterion for us in the workshop was and remains reliability. So that after a shift, in dust and vibration, the device turns on and does its job without lengthy settings. This is precisely what, apparently, LONGI is focusing on when creating its equipment for the mining industry. Simplicity of execution of key components, maintainability and understanding of real operating conditions - often this is more important than any “smart” ones. functions.