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Servo Motor Repair Blog

Servo & Spindle Motor Technical Support2020-06-02T16:50:38+00:00

Servo & Spindle Technical Support

servo & spindle motor technical support

Servo & Spindle Motor Technical Support

Maintenance personnel should be aware of the potential issues that may arise when you have a servo or spindle motor in production. For those in need of technical assistance, we’ve got you covered. Below you’ll find a list of common issues you may across with your servo or spindle motor and some simple solutions to help you resolve them. If you’re in need of immediate assistance, please reach out. You can give us a call at 860-632-0164 or you can email us at

AC Servo Motor Support

We have an entire department dedicated to AC servo motor repairs. Our technicians are very knowledgeable about a variety of manufacturers and they can help you troubleshoot any alarms or issues you may be experiencing. Some common AC servo motor issues that may arise include:

  • Absolute battery alarm
    • Solution: Make sure your machine is powered up before changing all the batteries in the control cabinet.
  • Abnormal high load percentages on any of the axes
    • Solution: Wipe and oil the ways and ball screws before running the machine.
  • Z axis brake holding
    • Solution: First, block the head of the machine to ensure that the head doesn’t drop. If the brake is easily accessible, then it can be cleaned out to remove oil and other contaminates. If there is an internal brake inside the motor, it will need to be removed for rebuilding.

DC Servo Motor Support

Our DC servo motor technicians are equipped with the necessary tools and resources to provide our customers with technical support. If you have a DC servo motor in production, you may experience some of the following issues:

  • High current alarms
    • Solution: Check the armature circuit with a megger to see if it has low resistance to ground.
  • High pitched squealing noise during startup
    • Solution: Try running the motor in both directions several times. The armature may have some corrosion from sitting awhile. Once the commutator is clear of corrosion, the high-pitched squealing should quiet down.
  • Position alarms
    • Solution: The glass wheel on the encoder may need to be cleaned with an alcohol wipe. Remove any oil, film, or debris that has settled.

Spindle Motor Support

Our spindle motor department is qualified to diagnose any issues you may be experiencing with your spindle motor. Our technicians have years of experience and they can provide you with the technical support you need to get up and running. Some issues that may occur include:

  • Noisy spindle bearings
    • Solution: Run the spindle motor at a low rpm to heat up the motor and solidify the grease that is in the bearing cavity.
  • Strong vibrations since the last time you ran your spindle motor
    • Solution: Let the spindle warm up at a low rpm before running parts. Check to make sure the coupling is tight. If the coupling has any kind of rubber spider make sure it isn’t cracked or broken.
  • Higher than normal load reading on your control
    • Solution: Make sure the spindle is free of any binding or unnecessary preload. If you have a belt running the spindle, check to see if the belt has proper belt tension and that it’s free from any cracking or splitting.
  • Orientation error during a tool change
    • Solution: Verify that the sensor is working correctly. Check to see if the proximity switch for the orientation is going on and off. Most proximity switches have little LED lights on them that will light up when activated.

Still Need Assistance?

If you’ve tried these solutions and you still need assistance, don’t hesitate to contact us. You can call us at 860-632-0164 or you can email us at Our technicians are readily available to help you troubleshoot.

Oil and Coolant, A Killer of Servomotors2019-10-15T02:17:06+00:00

Oil and Coolant, A Killer of Servomotors

Coolant and Oil in Your Motor

Your machine is down and you pull out a faulty servomotor and send it out for repair. The diagnosis is quick, there is coolant or oil in your motor and it needs to be rebuilt. Your motor had a seal on the shaft, sealed plugs, and gaskets between all of the exposed parts. How did your servo motor fill with oil?

There are a number of common routes liquids can take to get into your motor. You need to know these routes in order to prevent liquid intrusion from happening again.

Keep Coolant and Oil Out

Replace Shaft Seal When the Motor Is Worked on

Routine maintenance? Replace the seal. Changing bearings? Replace the seal. It is common for maintenance personal to reuse old seals versus replacing with new ones due to time constraints, budget, or laziness.

Even Environmentally Sealed Plugs Leak over Time

Replace worn plugs especially if there are loose pins that liquid could get around.

Servo Motor Connectors Need to be Mated

Even sealed connectors need to be mated with matching sealed cable connectors to ensure proper protection. Unsealed cable connectors will allow contaminants into gap between motor and cable connectors. As no seal is perfect, this unnecessary exposure to the plug surface will lessen the time it takes for contaminants to infiltrate the connector.

Stacked Laminations Allow Liquid to Leak through

AC servo motors have a stator that is made up of stacked laminations which will allow liquid to slowly leak through them. Some brands, such as Yaskawa, put a thin metal case around the stator to prevent liquid intrusion. Many other manufacturers such as Fanuc do not and just paint over the laminations. We have found that sealing the laminations with a two part epoxy paint significantly reduces the chance of contamination through the laminations.

Avoid Direct Spray on Servo by Oil or Coolant

Make sure that your servo is not being directly sprayed by oil or coolant. If it is not possible, there are many custom solutions out there to modify the motor or cabling to limit exposure.

In Summary

These are some general tips on preventing liquid intrusion into your servo motor. If your servo motor is flooded and you need help send it in to us and we will repair your servo and work with you to find a way to prevent flooding in the future.

Fanuc Servo Motor Repair Part Inventory2016-12-21T06:40:46+00:00

Fanuc Servo Motor Repair Part Inventory

Repair Part InventoryFanuc is the largest manufacturer of automated machinery in the world. Yet, a majority of the replacement parts needed to maintain Fanuc motors and machines have 16-20 week delivery times, if they are available at all. Ultimately Fanuc limits what “end users” can and can’t do to their machines. Servotech knows that our customers can’t wait 16 weeks for a part, and can’t have a machine down for 16 weeks. We also know it’s impractical for our customers to stock every part they may need, just in case the motor breaks.

Since Fanuc has limited part availability, Servotech has made it our policy to stock as many Fanuc servo motor components as we can. By inventorying more parts, different parts and higher quantities of all parts we eliminate the 16-week delivery time. From spindle motors fans to sensors, we have a healthy supply of the most commonly used components that are vital to Fanuc servo motor and Fanuc spindle motor repairs.

Even though we stock a large quantity of parts, there is the challenge of obtaining servo motor parts that completely unavailable. We came to a point where we either had to give up or get creative. We chose creative ingenuity. We now stamp our own Fanuc Fanuc Partsgaskets for back caps and conduit box covers. Through the use of additive manufacturing (3-D printing) we can recreate or replace small or easily broken plastic components right in house. In the case of some spindle motors we have even re-designed the motors with hybrid bearings.

It is because of these measures that Servotech is able to offer a reliable, rapid response option for Fanuc servo motor repairs, as well as a multitude of other manufacturers whose parts are un-obtainable. Our parts are as good as, or even better than, the original Fanuc components, and our response time for repairs leads the servo motor industry. Ultimately we work hard every day to keep our shelves stocked with parts, so you can keep making parts.


Maintenance & DC Servo Motor Repair – Undercutting2016-12-21T06:45:03+00:00

Maintenance & DC Servo Motor Repair – Undercutting

Undercut Your Motors, Not Your Success

Did you know that changing the brushes in your DC servo motor may fix some of your issues and keep you running in a pinch? Did you also know that a brush change is only a temporary fix?

DC Servo Motor Repair - UndercuttingIt stands to reason that as brushes wear out. The carbon they are comprised of turns to dust, which only has one place to end up – inside your servo motor! Changing the brushes is a good maintenance step, but it is also an admission that at least one set of brushes worth of carbon is now caked on the inside of the motor.

Furthermore, as brushes wear down, so does the copper motor commutator. Over time a commutator can develop a ridge or grove where brushes have been riding, causing brushes to wear out more quickly or not make proper contact, which leads to higher current draw.

When brushes wear improperly the excessive carbon can get lodged in between the commutator bars and cause a short circuit. The only way to make a DC motor last indefinitely is to rebuild it.

DC Servo Motor Refurbishment – Done Right by Servotech

At Servotech we remove the motor armature and put it through a process known as “Undercutting.” A small toothed blade is actually used to clean out the grooves in between commutator bars, then the armature is put in the lathe and all of the bars are turned down to one smooth surface. Once the bars are smooth, consistent and clean, the motor can be rebuilt, and the brushes can be set properly so that they will run true, and last.

For more information, read about our DC Motor Repair Process or see our article about DC Servo Motor Brush Wear.

Find Authorized Servo Motor Repair2016-12-21T07:02:01+00:00

Find Authorized Servo Motor Repair

Servo motor repair is a specialized challenging field. Servo repair techniques and procedures are often the result of companies who have researched through trial and experience. Servo motor manufacturers like to model their business after the automotive industry; constantly pushing new products lines, innovating year after year, and encouraging the sales of newer, faster and more precise machines.

A lot of companies out there throw around terms like, “Qualified Servo Motor Repair Center”, or “Official Servo Motor Authority”. It is a strategy in search engine optimization to favor certain words and phrases. There is no harm in turning a phrase, except when it is deliberately misleading.

The questions is: “How can you determine if a repair shop is a legitimate authorized servo motor repair center? Is it possible to confirm affiliation with a servo motor manufacturer?” When it comes to servo repair, the shortest response is usually – no they are not authorized, and they are not affiliated!

3rd Party Servo Motor Repair Shops Are Rare

Most manufacturers of CNC machines, and by association servo motors, are not interested in having third party shops repair their equipment. Companies like Fanuc and Mitsubishi do offer repair but at prices that promote buying new servo motors and machines. Because large manufacturers do not find it cost effective to repair their equipment, they just don’t. Additionally, they have no interest in certifying other companies as authorized servo motor repair facilities.

Authorized Servo Motor Repair Claims

Beware the use of servo motor factory logos on websites. It doesn’t take a lot of effort to copy and paste an image of a logo and incorporate it into a website. This can lead consumers to misconstrue a false connection between the motor manufacturer logo and the servo motor repair company. Never assume that a logo is the equivalent of a factory certification.

Some companies use phrases like “Master Servo Motor Repair Center,” and “Primary Servo Motor Repair Center,” to make an implication that there is some connection between the servo repair shop and the servo motor manufacturers they repair. Using language to mislead a customer into choosing a service on false pretenses is dishonest.

Perspective can be difficult to maintain, especially with a machine down, and the need for quick action.

Truly Authorized Servo Motor Repair

Servo motor repair, like any other industry, has its leaders who thrive on the quality of their honest work. At Servotech is has always been our mission to exceed customer expectations and servo motor manufacturer standards. Many of our servo repair processes result in a servo motor that is better than a brand new one from the manufacturer.

During our years in business, we have earned the distinction of being an actual authorized servo motor repair center for some of the world’s biggest servo motor manufacturers. We maintain factory drives, rigorous procedures and the very best servo motor repair procedures to maintain these certifications. Find our more on our:

Stop Overpaying for an OEM Servo Motor!