Archives for August 2020

Changes in voltage have a significant impact on current. When it comes to supply voltage variations, starting current and running current respond very differently. A drop in line voltage will result in a lower starting current and a higher running current. A rise in line voltage up to 5% will increase starting current and slightly reduce running current. If the line voltage increases more than 5%, both starting and running current will be higher. As a general rule of thumb a 1% voltage imbalance can create a 7% current imbalance and a motor with a 5% voltage imbalance has a reduced capacity of 25% and should not be run unless the motor is de-rated accordingly.

Visit the PdMA YouTube site at https://www.youtube.com/channel/UC-cUONWaudkKReNwC0PPXMQ to see a variety of case studies from the electric motor reliability industry.

Siemens electric motors: Quality and innovation from the very beginning.

Siemens electric motors are synonymous with quality, innovation and the highest efficiency. We cover the complete range of industrial motors – synchronous as well as asynchronous: from standard electric motors through servomotors for motion control applications up to high voltage and DC motors. This is all based on more than 150 years of experience.

Have you had issues with motors that are stored in your facility? Have you experienced poor meg readings and/or bearing issues?  Here are some tips for keeping your motors running optimally:

1. If your motor is in an ambient above 140ºF, it should be in an enclosed ventilated area.
2. Does the temperature of your motor get below an ambient below 40ºF?  Heaters should be installed and energized.
3. Is the area your motor is in experiencing  large swings in temperatures? You could be collecting moisture.  
4. Rotate shafts bi-monthly.
5. Megger motors bi-yearly.
6. Grease ball bearing motors yearly.
7. Sleeve Bearing motors: Install oil while in storage and drain when moving.

If you have any questions, please feel free to call your Account Manager, or call 217-428-6621

Decatur Industrial Electric offers storage for motors and the staging of new motors for projects! 

Often when we hear technical terms involving power quality such as total harmonic distortion, common coupling, and harmonic voltage factor our eyes glaze over and we throw up the white flag. Yes, there are some impressive algorithms involved in some of those terms, but in the maintenance and reliability world we can look beyond the details to the end game which is heat. Heat has been identified as the number one killer of electric motor insulation and the bottom line is poor power quality creates excessive heat. High distortion levels in the power being delivered to a motor will result in current flow through the motor that performs no real work. This harmonic current added to the real work current often results in the motor running in an overloaded condition electrically even though the horsepower delivered is at or less than rated horsepower.