Ecmweb 16854 Drive Maintenance Pr
Ecmweb 16854 Drive Maintenance Pr
Ecmweb 16854 Drive Maintenance Pr
Ecmweb 16854 Drive Maintenance Pr
Ecmweb 16854 Drive Maintenance Pr

Proper Motor Drive Maintenance

Oct. 17, 2017
Minimize breakdowns by taking the proper steps to keep equipment running as designed.

Few business operations can afford unplanned downtime, which typically causes frustration, eats into profit margins, and can lead to workplace injuries, accidents, and health issues. When you have production targets to meet that require the use of equipment, it’s essential that the motors, motor drives, and other machinery runs safely and smoothly. With regularly scheduled maintenance, you can minimize the chance of breakdowns, especially those caused by common drive problems. Follow these steps to maintain drives and ensure controls are running as they should.

#1: Start with safety

Check the recommendations and schedule from the manufacturers. Even if these don’t contain specific instructions, it’s a good place to start. Only qualified personnel should conduct maintenance on motor drives, and it’s imperative to follow good safety practices, some of which include:

• Lockout/tagout (LOTO) protocols, which are the OSHA standard for preventing release of hazardous energy during servicing and maintenance activities.

• Arc flash safety through compliance with the NFPA 70E Standard.

General safety measures include ensuring the equipment is disconnected from all power sources, and the maintenance area has sufficient ventilation to enable staff to breathe comfortably — even in the presence of chemical products used for cleaning and repair.

#2: Take clean air measures

Clean air is necessary for all motor drives to function properly, so clean or replace any cabinet air filters as often as necessary to maintain airflow. While it’s ideal to replace cooling fans every two years, it’s also helpful to check them quarterly — and swap out any faulty fans before they fail completely. Deferring maintenance until problems arise is a surefire way to lose productivity. In addition, faulty cooling equipment can lead to the failure of other parts, requiring more costly repairs.

#3: Review connections

Using the drive manufacturer’s torque specifications as a guide, check all the accessible connections at least once every year. When you’ve done so, disconnect all the motor leads from the drive, take insulation resistance readings, and log them for future reference. Ensure the electrical insulation is in good working condition, and measure the winding resistance, which can provide good information about the condition of the equipment and its components.

#4: Replace DC capacitors

DC bus capacitors are a critical component of AC motor drives. Many manufacturers recommend replacing them at intervals. This is especially important for larger drives, which should be replaced every five to seven years, although it might not be practical for smaller drives.

#5: Consider an upgrade

In instances where drives are older and obtaining replacement parts has become difficult, it might be worth considering a drive upgrade or retrofit. For DC drives, a planned replacement with an AC drive and motor may be advisable.

#6: Testing

When all your maintenance work is complete, run the drive at full speed, and take input and output voltage and current readings using an oscilloscope, if possible. Keep a log of all the readings. If full speed operation isn’t practical, run at the fastest steady speed that is appropriate. Uncouple the motor from the load (if required).                            

Conner is the Dallas service manager for Control Concepts and serves on the Advisory Committee for the Electronics Technologies Department at Texas State Technical College. He can be contacted through www.controlconceptstexas.com.

About the Author

Jeff Conner | Dallas Service Manager

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