Capital spare transformer - A valuable asset in times of disrupted supply chain
Capital spare transformer is very important element to support high availability of a medium voltage variable speed drive system (MV VSDS). While this has always been true this service became even more crucial in today’s world paralyzed by supply chain disruptions.
High availability of a production plant is key for business success. When the plant is down the owner loses production. Moreover, the company also loses trust. And finally it loses considerable amount of money. As the installed base of variable speed industrial drives is growing the availability of the variable speed drive system, VSDS (or power drive system, PDS, if you like) gains on importance as well.
High MTBF ≠ High availability
Now when talking about availability most people, including engineers, may do slightly incorrect consideration. In their view the VFD is the drive system component with lowest availability.
Well, it is true that the mean time between failures (MTBF) of a VFD is typically shorter than the transformer or motor. However, at the same time the VFD can typically be repaired much faster. And there is really a BIG difference. For example, when a VFD component (e.g. semiconductor) fails, it can be replaced within several minutes assuming that the spare parts are stored on site and the maintenance team is properly trained. There is no need to dismantle the VFD and send it to a service workshop or the factory.
In contrast, the situation may look very different for a VFD transformer. It has very high MTBF and is unlikely to fail. But what if it fails… Then the user may start shivering. The damage may be quite severe. It may take several days or even weeks to repair the transformer and put it back into operation. In case of larger damages it may be necessary to send it to the repair workshop. And in worst case new components (e.g. windings) or a completely new transformer has to be manufactured. The consequences are horrific…
- Transformer mean time between failures (MTBF): 500 – 1’000 years
- VFD mean time between failures (MTBF): 8 – 12 years
- Transformer mean time to repair (MTTR): 600 – 1’000 hours
- VFD mean time to repair (MTTR): 4 – 8 hours
Supply chain disruptions
Current market situation does not make it easier for us. The disruptions in supply chain, increased lead times, bottleneck in transportation and the overall unpredictability put the business owners even at bigger risk. Shipping transformer to the workshop takes more times. Waiting for spare parts takes longer. Manufacturing a new unit after a fatal failure may take very long.
Even if “your manufacturer” is local, he most likely does not produce all transformer components in house. Some parts mostly likely come from subsuppliers. Therefore, he might be exposed to various suppply chain shortages and disruptions.
Mitigation strategies
So how to protect yourself and your business? You have several options:
1. Don’t do anything
Transformer is proven to be very reliable so why to worry? It might be a strategy but it is certainly associated with risks. You may be lucky and do not experience any major transformer fault leading to unplanned shutdown. But if it happens the consequences can be severe. In our view it is unnecessary to undergo such risk.
⇒ Risky
2. Have a capital spare transformer on stock
That is the other extreme. In the past companies used to have capital spare equipment. Nowadays it is not popular, particularly by the economists. The capital spare is an unproductive asset that sits somewhere in your warehouse under a thick layer of dust. You may never really need it. And if you need it after all it may not work as it was not maintained over the years.
⇒ Expensive
3. Use rental transformer
The third option is to use a rental transformer service. This may be the best choice actually. You don’t need to invest into the capital spare, its storage and maintenance. Instead, you can use that capital to expand your business. And still, if a transformer faults happens the future does not have to be dark.
But here is a point. Converter transformers / VFD transformers / VSD transformers mostly differ from ordinary distribution and power transformers. It may not be easy to find one to rent. Do not underestimate it. You can just open your web browser and try to find one…
My experience
During past 10 years I have witnessed several transformer damages. None of them could be repaired quickly. And the user was always caught unprepaired. It usually took several weeks or even months. Mostly it was required to send the unit back to the factory or for example to manufacture new coils and send them to site. That easily takes 6-8 weeks. In some cases the customer had multiple drives and downtime of one of them was not so big deal. In other cases, however, the consequences were much more severe. Like auxiliary drives inside a medium size combined cycle power plant with unplanned downtime just before the winter season. Or a blower drive inside metals plant that urgently needed to keep up the production. Or a gas compressor drive located in remote area.
We were calling the factories and partners to figure out whether there is a transformer unit somewhere that could be used (maybe from a cancelled project or so). It did not work. You would need huge portion of luck to find a transformer that fits your VFD topology, matches the grid voltage and grid frequency and is free to be used.
Our solution
We decided to fill in such gap and offer converter duty transformer to rent. Our more than 10 years of experience from medium voltage drives along with the market knowledge allowed us to specify, design and purchase transformers that fit many VFDs from renowned brands such as ABB, Ansaldo/Nidec, General Electric (Converteam), Ingeteam, Schneider or Siemens.
Examples of compatible VFDs:
ABB (ACS1000, ACS6000 / ACS6080 LSU), Ansaldo (Silconvert TN3300 V), General Electric (MV7000), Siemens (Sinamics GM150) and many more.
The transformers support range of input voltages, are made for VFD duty, use phase shifting to reduce harmonics, can be installed both indoors and outdoors and can substitute original dry type of liquid-immersed transformer.
Yet, we do not cover every VFD model. Therefore, it is highly recommended to check it upfront. It does not cost you anything besides few minutes of your time. And you will know whether we have a solution for you or not. If so, you just save our contact data. If not then you are at least aware of it.
Here is the link to our simple questionnaire to figure out whether our capital spare transformer fits your VFD:
Wrap up
Here is the take away summarized in few bullet points:
- Transformers are very reliable → You may never use a capital spare.
- However, in case of a transformer damage, the repair time is considerable.
- Transformers supplying VFDs have special design and are not easily available.
- Current global disruptions in supply chain further increase the lead times and the risks.
- Prepare a plan before something happens – find out whether there is a rental option for your drive transformer.
- Check out our capital spare transformer rental service to find out whether we could back you up in extraordinary situation.
Our capital spare transformer rental
Our transformer rental concept may be the ideal solution for your company. Yo don’t need to have your own capital spare transformer and therefore the investment and storage cost can be avoided. At the same time you are not fully exposed to all the risks when the original transformer fails. The rental service effectively dampens the impact on your business.
You can imagine our service like an insurance. However, unlike an insurance you don’t pay anything unless something happens. And the rental cost is just a little fraction of the liquidated damages that your company would face due to unavailability.
Despite our best efforts we can’t guarantee that our rental transformers are compatible with your VFD. Therefore we recommend you to check it in advance by filling a short questionnaire. You will get a response from us whether our transformer matches or not.
You can download our brochure describing transformer rental service:
Or contact us directly through the form below:
