We hear people lament about the pros and cons of spare inventory every week. Spare equipment inventory is a necessary evil with many problems and pitfalls attached. Do we have the correct spares in stock, how long have they been on the shelf, what is the environment that they are stored in, can I use one piece in place of another?

When you are running a manufacturing plant 24/7 and down time costs you many dollars in production, having a spare inventory on the shelf is very important to support your maintenance department.

The algorithm says we should stock that many. We are inundated with software programs that crunch the numbers on inventory levels. Common sense dictates that we should not just rely on numbers spit out by a computer. Good questions for the store room specialists include “How many turns do you get on each piece in inventory, how many of each do you stock and why?” I have heard answers from “Well we keep this important servo drive in stock because ours fails once a year.” “We keep three of these drives on the shelf because we have had problems with failures right off the shelf.” “We don’t repair any drives we just throw them away and purchase new replacements.” “We just expedite and fly all new parts in when we go down.”
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How can we help? IPS has solutions for all of these potential issues. We can even be considered an extension of your store room inventory - without all of the associated costs. Send us your second or third spare, let us repair them and keep them on our shelf for you. There is no cost to you until we actually ship you the drive or servo motor. Send us those drives and servo motors that you were going to throw away. We will repair them and keep them on a shelf in our facility as spares for you; again at no cost to you until you need them.

Where do you go to find obsolete parts? Many store room specialists are struggling to find spares for units that are beyond the legacy stage. Most scour for surplus equipment on the internet and no one really knows the conditions of these pieces. IPS has relationships with many vendors in the USA, Asia and Europe, which enables us to source parts and replacements for older equipment.

An alternate solution. We have partnered with OEM’s to find cost effective solutions for manufacturing plants that are not ready to upgrade their entire systems yet. Including custom integration plans and smaller retrofits to current equipment.

MRO Inventory optimization is critical to a successful production business.  Has your integrated stores formed a partnership with an OEM quality repair facility?   Is that repair facility interested in doing a critical spares inventory program?  Is that repair facility interested in helping you stock some spare inventory for exchange?  If you answered “no” to any of these questions, then you should give IPS a call.
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Always looking for solutions. If your spare parts are at the legacy stage, or beyond, we may be able to help you with repair of your equipment, locating replacement equipment, or offering replacement options. 

Industrial drive repair is an important conversation that goes on in many manufacturing facilities daily. I sat down recently with a facilities maintenance team at a local manufacturing facility to discuss drive repair and found out they are throwing their drives away instead of repairing them. Their big question was whether it was worth repairing a drive or better to just buy a new one. 

Lots of points come into play here. How readily available is a new drive? Is a 50% or more cost savings worth repairing a spare unit to have on the shelf? What is the pain involved, time and money, to retrofit drive communication and technology from your current drive configuration that may be obsolete to a modern drive? How will your “process” work with the new technology in place? What is the “active life” expectancy of the new drive, meaning how long before that technology is outdated, replaced and you are in the same position?  

VFDs (Variable Frequency Drives) have come down drastically in price over the last few years. With it the quality and relative life have decreased as well. I have seen brand new drives last 15 or 16 months, just past some vendor’s warranty period. Do you know where your drive is being manufactured? Or who is really manufacturing your drive? Sometimes drive manufacturers have “other drive manufacturers” make drives for them. In the standard VFD family, most standalone VFD’s are often more economical to replace rather than to repair. Most reputable Industrial Repair facilities will tell you your unit is not economical to repair and offer you a replacement option.

Which Industrial drives are worth repairing? Let’s review some examples where repairing an Industrial drive might be a better option to replacing it.

When Does Industrial Drive Repair Makes Sense?

The unit is a specialized VFD: Some facilities have machines with specialized VFDs and customized software. It’s just not always as easy or inexpensive to replace these drives. IPS can assist in the repair of these specialized VFDs to keep the customers' machine and assembly line up and running.

Large horsepower drive unit: The larger the HP of a drive the more cost effective it is to repair the drive unit. Modular drive systems are the norm on many of these large horsepower drive units. Troubleshooting can help to isolate the issues to a particular drive module assembly that can be separated from the rest of the configuration and repaired at a considerable cost savings to replacement. IPS sees many high horsepower modular drive systems as well as some medium voltage drive units.

Servo drives: Servo drives are typically part of a whole drive system customized specifically to an application. They can be difficult to troubleshoot, not so readily available and expensive to replace. These are perfect candidates for a repair or exchange program. Let IPS help you get a repair or exchange program started and setup.

DC Drives:  DC drives, although not as common, as variable frequency drives, are still in use in many manufacturing facilities. These drives are a perfect example of when a repair is favorable over replacement. Many of these units can be repaired without the added expense of retrofitting a new drive to a process and incurring the problems associated with a retrofit. Of course, if upgrading to a new DC drive is a feasible or necessary option - IPS can help with that as well.

There are large numbers of specific Drives in your facility. Once you have spare parts and drives in place, your maintenance personnel have developed experience on testing, repairing and troubleshooting those specific units. It is often more economical to set up a repair and exchange program for the specific drives that you have large quantities of in your facility than to disrupt “the norm” by installing new equipment. One of the questions I ask a customer considering replacement or retrofit to new, is how long can they afford to be down trying to retrofit a drive system and how much outside help did they want to pay for. These are costs not often thought of when replacing drives. 

We have many strong relationships with many customers experiencing this same exact situation. It is often important to weigh the total cost of replacement, integration, training, etc., with the costs associated with repair.

How are drives typically repaired and tested?

What typically happens when a drive arrives at a reputable repair facility? The drive is logged in, pictures are taken of the unit to document the condition it was received in and any visual damage is recorded. The repair is assigned to a qualified technician. The appropriate repair manuals are given to the technician along with the customer’s notes and complaints. The drive then goes through a series of powered off testing, to see if the drive is safe to power on. Once it is determined that the drive can be powered up safely, or if the logic side of the drive can be powered up independently of the power section, it is powered up to read the alarms or faults recorded on the drive's fault logger. This also gives us the opportunity to save the customer’s parameters before any work is begun.

IPS’s technicians work on a custom tablet software system that allows them to record all initial testing, take pictures of all damaged or suspect components as well as do a thorough evaluation of the drive that is in for repair. The customized tablet software pushes the initial inspection report to the inside CSR who then prepares a quote for the customer.

If the customer needs pictures of the damage, a more thorough repair quote or a possible cause of failure report, this is all available upon request.

Once the job is approved the technician will order all the parts necessary to correctly perform the repair. One thing that needs to be kept in mind is that a reputable repair facility will replace all the questionable or limited life components at the time they are doing that repair. What do I mean by this? Sadly, some less reputable repair facilities tend to replace just the one faulty capacitor, IGBT or diode, instead of replacing the whole set or all of the limited life components inside the unit.

If you read most OEM service manuals they specifically tell you that there are limited life components inside their units, and depending on the working hours of these units, they should at the very least have the cooling fans and electrolytic capacitors replaced at specific intervals to avoid catastrophic failures.
Once the unit is repaired it under goes a series of tests including a run-in procedure that mates the unit with the appropriate motor, controls, etc. that are found in most customers’ manufacturing facilities. The final repair report is completed using the tablet software, a video is taken of the running unit and it is prepped for shipping.
 
What typically goes wrong with Industrial drives?

Most industrial drive units are generally reliable, but they are drastically influenced by the environment in which they operate. Such things such as power fluctuations or surges in power, harsh environments with extreme cold or heat, external contaminates such as dirt, or fluids; as well as the quality of installation and preventative maintenance program practiced, can all greatly reduce the life of the drive system. A good maintenance program and a partnership with a reputable drive repair facility are a must.

Let us review some of the issues we discover in more depth:

Loose connections. Do you own a thermal camera? Well if you do take a walk around your plant and take some pictures of your drives at their connection points. You may be surprised by the high heat around your connections. Not surprisingly, this is a problem. Loose connections lead to many drive failures, both incoming and outgoing power connections are the typical culprit here. Check these simple things first and it may save you an expensive drive repair with long down times down the road. IPS can help you with any thermal imaging needs you may have.

Cooling Fans. Cooling system failures in drives are a major cause of drive damage. Some drives have built in alarms to let you know these issues are arising, but regular maintenance is the best option here. Identify and keep some spare cooling fans in your parts room. This may save you an expensive melt down in the future. Overheating drives can, and almost certainly will, cause major issues long term. Check your fans often. If you need help with replacement parts IPS can help.

Electrolytic Capacitors. These are limited life components. Check any manufacturers data sheet on capacitors and they will spell out very clearly for you the working hours of these components. They are limited life components and should always be replaced once they approach the OEM’s recommended end of life. Don’t be fooled by your DMM (digital multi meter) or ESR (equivalent series resistance) meter into thinking these are 100% good tests for electrolytic capacitors. I have seen capacitors with holes blown in the side of them test good on both DMM and ESR meters. Overheating the drive greatly shortens the life of electrolytic capacitors even more.

Power Semiconductors. We commonly see IGBT, SCR diodes fail in drive units. The true question to answer here is did they fail because they exceeded their limited life, or did something else internal or external to the drive cause their failure. Determining this will go a long way in the working future of this drive.  Again, IPS can help with replacement parts. 

Circuit boards. Circuit boards are typically not a common issue in drive failure. Boards are sometimes damaged by the failure of other power components. IPS utilizes a flying probe circuit board testing system that when used properly discovers failing components, failed components, faulty solder joints and bad traces. Unless the board has suffered dramatic physical damage, most of the time they are repairable. It is a good option to have the boards checked by a secondary testing system, flying probe technology, prior to reassembly of the entire drive unit. Come in for a demonstration of how flying probe technology works in board repair.

VFD Software or parameter programming. Sometimes parameter changes, software updates and electrical faults can cause programming and software to become unstable, corrupt or have issues. Most of the times our technicians are able to reload your parameters, if available, or re-flash software to make a unit function properly. A lot of this is dependent on software availability.  Check with an IPS specialist and see if we can help.
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IPS offers more than just drive repair, talk with one of our sales professionals to see how we can setup a repair program for you.