Monthly Archives: August 2016

Difference Between VFD, Servo Drive Repair

Posted August 31, 2016 by Pepper Hastings

Categories: Blog, Industrial Electronics Repair

Tags: ,

Servo drive repair differs from VFD repairs in several ways, including being a bit more difficult to troubleshoot. Also, servo drive repair usually requires that the servo be connected back to its intended system to ensure it's repaired correctly (something that's extremely difficult to replicate in repair shop conditions).

A VFD (variable frequency drive) is generally used to control a squirrel cage type motor, where both stator and rotor are of a wound type to create the magnetic flux.

Servo drives are used to control permanent magnet motors. They are called permanent magnet motors because they use rare earth magnets in the rotor to create a much higher magnetic flux for their given size. This enables the motor to create more torque in a much smaller motor size. This means the motor has a lower inertia to accelerate and decelerate much more dynamically than that of the asynchronous squirrel cage type motor.

servo drive repair

Servo drive repair can be more difficult to troubleshoot in a shop setting than a VFD.

On the controller side, the servo controller can calculate a complex path and maintain the position along that path with varying loads and speeds. Many servo controllers are multi-axis or can be daisy chained to make multi-axis moves to follow complex paths.

Because of these differences, a Servo drive repair is much different than troubleshooting a standard VFD.  When isolating the issue with a servo drive, you must consider the entire system, drive, cabling and motor.  It's difficult to troubleshoot a servo without all three of the main components present.  And since servo drives are designed to run a specific magnetic flux motor, it is close to impossible to test them outside their designed system.

Check These Prior to Servo Drive Repair

We've compiled a list of the top simple issues that should be checked before sending in your unit for servo motor repair. Please note this is not meant to be an insult: I very often spend time trouble shooting over the phone to eliminate simple errors or problems. Double check everything before electing to send in a motor for repair, otherwise time has been lost in both the shipping and evaluation.

  1. Occam's Razor: The simplest explanation is most often correct. Make sure everything is plugged in. Try turning your drive and controller off, and reboot.
  2. Check All Servo Motor Cables. Look for items such as Broken Wiring, Loose Connections, Dirty and Corroded Connectors - bad connections can interfere with the power and signals that are vital to proper servo operation.
  3. Check Overall Cable Conditions
  4. Check Grounds and Shields. Just because a cable is in good shape doesn't mean it is properly grounded. Keep in mind that grounds and shields are important for protecting signal wires from harmful noise that can disrupt feedback communication. Motor power grounds are important because they facilitate the tripping of over current protection devices. If a motor has an inconsistent ground that is not continuous with a drive ground the power cable can throw an unmanageable amount of noise onto a properly shielded feedback cable.


If all this checks out, then you probably have a servo drive issue that requires shop servo motor repair.  Use a repair shop that can help you isolate the problem, but as mentioned above understand it could require some additional testing at your sight AFTER it's worked on at the shop. If your repair facility also has industrial field service technicians, so much the better. They can can help you with onsite troubleshooting of servo systems.

Marc Phelps is manager of the Innovative-IDM repair facility in Houston. You can contact him at

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Baton Rouge Flooded Control Panels

Posted August 30, 2016 by Pepper Hastings

Categories: Blog, Industrial Electronics Repair, Industrial Maintenance

Tags: ,

Fairchild uses a pressure sprayer on an electrical panel. No, it's not plugged in.

Fairchild uses a pressure sprayer on an electrical panel. No, it's not plugged in.

Our customers and employees in Baton Rouge continue to endure dire conditions from the staggering flooding in that area and throughout southern Louisiana. One of our customers, a printing plant, sustained horrible damage. Everything flooded. Office turned upside down. Every control panel went under water.

On the scene, IIDM field service technician from our Baton Rouge office Joey Fairchild surmised the situation: "We are attempting to save all the wiring, term strips and relay sockets. The plan is to replace every component. I’m working on that now. I’ll let you know how it goes in a week or so. Power stayed on. However we will need to clean distribution gear at some point."

Fairchild said the plan is this:

  • Pressure wash the mud and oil coating with a degreaser. It was all wet anyway.
  • Dry with fans 1-2 weeks while parts are ordered and delivered.
  • Send flooded motors out for rebuild.
  • Send high HP drives in to IIDM repair facility for rebuild.
  • Megger test all wiring, with components removed, to find shorts/moisture.

The photos and video tells the story better than words.

Baton Rouge Flooded Control Panel from Innovative-IDM on Vimeo.

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Motor and Control Applications: Total Cost Counts

Posted August 26, 2016 by Pepper Hastings

Categories: Blog


When designing a motor and control application, how often do we actually take the total cost of ownership into account? Are we "saving money" by cutting corners on conductor sizes, ignoring voltage drop and imbalance in our designs? Are we sizing wires incorrectly? The real answer is we probably don't think about total cost of ownership often enough. We are usually faced with many constraints such as:

  1. Time: rapidly encroaching deadlines.
  2. Multiple projects on deck.
  3. Numerous other distractions that we face each and every day.
  4. Space available for components.
Motor and Controls Applications

Spending a little more money on the front end of a motor and controls application design can save a lot in the long run.

There was recent article on the Electrical, Construction and Maintenance website about some energy saving tips for motor installations. I shared this with my colleagues and received some interesting feedback about motor and control applications. It's a good read, so check it out if you get a chance.

One of our controls guys said, “I hadn’t thought of conductor size before from a cost savings over time. I usually push back on customers over sizing wire more than they have too. It effects our input breaker lugs being large enough.”

One of our branch managers commented, “Good Read.  Never even thought of voltage drop because of mis-sized wires!”

We all know the basic formula for Ohm’s Law E=I/R.  But how does that apply in this situation? The smaller the conductor the higher the resistance and therefore higher current. Higher current results in more electricity needed to perform the same amount of work.  As an Electrician and Maintenance Mgr. in my former occupations, I always focused on this aspect of new motor and control applications. I was usually able to get approvals by showing that by spending a little more on the front end we could save a lot more on the back end. That cost savings was essential to getting my projects approved.

Dave Oliver


We all know about using energy efficient motors but most of us don’t even think about conductor sizing, voltage drop, or imbalance. These also play important parts in the total cost of ownership. We try to point this out to customers we are working with, since a lower total cost of ownership = a lower bid on many projects.

Dave Oliver grows very, very hot ghost peppers and is a field service technician for Innovative-IDM's Memphis branch. You can reach him at

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Collaborative Robot Serves a Biscuit

Posted by Pepper Hastings

Categories: Blog, Rethink Robotics


We were at one of our customer sites yesterday showing off Sawyer, one of our collaborative robot models. The thing about Sawyer is that he's so easy to program for simple tasks. Obviously, in a manufacturing line setting there are additional considerations to fine tune. But this one-minute video underscores just how easy it is for an engineer to program the robot. That's IIDM's Jack Marsh on the left playing the part of tutor.

Collaborative Robot, Easy to Program, Serves Breakfast from Innovative-IDM on Vimeo.

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Pneumatic Air Dryer Saved $10,000, Downtime

Posted August 22, 2016 by Pepper Hastings

Categories: Blog, Pneumatics

Tags: ,

This SMC air dryer solution extracted nearly five gallons of moisture and oil from the facilities pneumatic system. The same moisture and oil that previously was passed through to the machine tool.

In just six hours, this SMC air dryer solution extracted nearly five gallons of moisture and oil from the facility's pneumatic system. This moisture and oil previously was passed through to the machine tool, resulting in replacement parts and downtime.

One of my customers had a challenge with his pneumatic air dryer. The pass-through contaminants were costing him parts, time and money.

His facility had in place Ingersoll Rand air dryers. But the dryers were not properly sized for the application. The result was the dryer was allowing inordinate amounts of water and compressor oil pass through to their machines.

This contamination caused by the mismatched pneumatic air dryer meant the customer had to keep replacing his pneumatic valves and cylinders (approximately $10,000 per year). Not to mention the downtime and labor time required to install the replacement parts. If you're not sure about how expensive downtime can be, check this out.

My solution was the SMC pneumatic IDU series air dryer (high inlet temperature dryer) and the AFF series filter. What you see in the photo is the amount of water that the new air drying solution removed from the system in a six-hour period, from 8 a.m. to 2 p.m. on a hot summer day.

The customer has been running the new SMC pneumatic air dryer set up for a couple of months and his system is running more efficiently. He is now recommending the purchase of another SMC pneumatic dryer set up for an identical compressor on the other end of his facility. This photo is a great example of how a properly matched air drying solution from SMC can solve problems -- and money and downtime --  in an industrial pneumatic system. --



Alberto Aguilar helps customers out of the Houston branch of Innovative-IDM. You can contact him at


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