Many variable speed drives and soft starters keep running long after they’ve disappeared from the manufacturer’s catalogue. That’s a testament to how well they were built, but it also creates a hidden risk. When an ageing unit fails and spares, software or support are no longer available, a simple fault can turn into weeks of downtime.
The good news is that an unsupported drive doesn’t have to mean a crisis. With the right plan, you can refurbish, retrofit or replace ageing equipment on your terms and keep your process running throughout.
How to tell if your drive or soft starter is obsolete
Obsolescence isn’t always obvious. Your equipment may still be working perfectly, but warning signs include:
- The manufacturer has declared the product end of life or discontinued spares support
- Replacement parts are hard to find or have long lead times
- Programming software or interfaces no longer run on modern computers
- Few engineers are familiar with the model
- The unit has been in service for decades, with high running hours
- The original manufacturer has merged, been acquired or changed product lines
If any of these apply, it’s worth planning ahead rather than waiting for a failure.
The risks of running unsupported equipment
The biggest risk is downtime. When a supported drive fails, a replacement part or like-for-like unit can usually be sourced relatively quickly. With obsolete equipment, you may be searching for second-hand parts of unknown condition, or waiting for a new unit to be specified, ordered and built into a panel.
Older drives can also be less energy efficient, lack modern communication and protection features, and be harder to integrate with current control systems. Ageing components such as capacitors and cooling fans become more likely to fail over time, so the risk grows with every year of service.
Your options for upgrading obsolete drives
There isn’t one right answer for every site. The best approach depends on the equipment, how critical it is and your budget.
1. Refurbish and upgrade the existing unit
Some older units can be brought back to full health with new power components and an updated controller, especially where the manufacturer has designed newer versions to fit the original footprint. This can be a cost-effective route that avoids panel modifications.
That’s exactly what happened in our Torqmaster 3000 upgrade. A seafood processor in Peterhead relied on a Torqmaster 2000 soft start, more than 20 years old and with over 50,000 running hours, to start a 550kW blast freezer motor. When it failed, we diagnosed a faulty thyristor module over the phone. The unit came back to our workshop, where we manufactured and fitted new thyristor assemblies and upgraded the controller to the latest Torqmaster 3000. As a direct physical replacement, it dropped straight back into place, with the bonus of USB programming and fault-finding. The original parameters were transferred, and the customer was quickly back to freezing. They’re now planning the same refurbishment for two more original units on site.
2. Replace with a modern equivalent
Where refurbishment isn’t practical, a new drive of the current generation is often the best choice. Modern drives offer better diagnostics, built-in communications, improved protection and often better efficiency.
3. Re-engineer the panel
Sometimes an upgrade is a chance to rethink the whole control system. A new panel can bring in modern drives, telemetry, better cooling and improved safety features. It takes longer to design and build, but it can extend the life of the installation by many years.
Keeping the process running during an upgrade
Whichever route you choose, the key question is how to keep critical equipment running while the work happens. That’s where temporary hire comes in.
In our 650Amp variable speed drive install, a North West utilities company needed to replace an old 350kW Vacon NXP drive running one of a pair of pumps at a wastewater pumping station near Morecambe. We installed a temporary drive panel from our hire fleet to keep the station operational while a replacement 650A NXP was sourced from Danfoss Drives. Once it arrived, our Danfoss-trained engineers removed the hire unit, fitted the new drive into the existing enclosure, reconnected the wiring and ran an identification run to optimise it for the customer’s new pump. The whole changeover was completed in a day, and the new drive came with an extended on-site repair warranty.
Careful planning makes a big difference on large installations too. In our NXC drive exchange, a 1MW induced draft fan drive at an energy recovery plant was removed, exchanged and recommissioned within 36 hours.
Planning your upgrade
To make an upgrade as smooth as possible:
- Audit your equipment. List your drives and soft starters with their make, model, rating, age and criticality.
- Back up parameters. Saved settings make commissioning a replacement much faster.
- Check the footprint. Confirm whether a new unit will fit the existing enclosure or needs panel changes.
- Review controls and communications. Make sure the new unit works with your existing signals, PLC or telemetry.
- Consider the motor. Older motors may need checking for suitability with a modern drive.
- Arrange contingency. Identify hire equipment that could run critical motors if the old unit fails before the upgrade.
Get expert advice
With nearly 40 years’ experience in soft starters, drives and control panels, Ralspeed can help you assess your ageing equipment, recommend the right upgrade path and keep you running with temporary hire while the work is carried out. Contact us to discuss your drives and soft starters.
Written by Neil Parsons, Technical Director – With over 35 years in electrical engineering across various sectors, these articles are written by a specialist with hands-on experience in electrical design and commissioning, PLC and variable speed drive programming and installation.
Frequently Asked Questions
What happens if my obsolete drive fails?
Without spares or support, repair may be slow or impossible. A hire drive or soft starter can keep your motor running while a replacement or refurbishment is arranged.
Can an old soft starter be refurbished instead of replaced?
Often, yes. Depending on the model, new power components and an upgraded controller can restore it, as with Torqmaster 2000 units upgraded to Torqmaster 3000.
Will a new drive fit my existing panel?
Sometimes. Modern drives are often more compact, but fit, cooling and wiring need checking. We can assess your panel before you order.
Can my old drive settings be transferred?
Parameters can often be recorded and reapplied, though a new drive may need retuning or an identification run for best performance.
Is Ralspeed a Danfoss drives distributor?
Yes. Ralspeed supplies and supports Danfoss drives, including the Vacon range, with installation, commissioning and servicing.
How long does a drive upgrade take?
Straightforward like-for-like replacements can often be completed in a day once the new unit is on site. Panel redesigns take longer, which is why hire is useful in the meantime.
How can I avoid downtime during an upgrade?
Use a temporary drive or soft starter from our hire fleet to keep critical motors running until the new equipment is installed.
