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Advice: Effects of High or Low Voltage on Motor Performance

  • September 2020
  • Number of views: 3838
  • Article rating: 3.0
Trade press article — RV News

To ensure the reliability of an RV’s electrical devices, especially electric motors, campers must know the service voltage of the hookup their RV is using. Teaching consumers to check that before they plug in the vehicle could save them many headaches.

Cool advice on hot motors

  • August 2015
  • Number of views: 4795
  • Article rating: No rating
Trade press article — Maintenance Technology

The effects of excessive temperature on motor performance are notorious. After moisture, they are the greatest contributor to bearing and winding failures. Understanding the source of increased temperature is key to correcting the problem and improving the reliability of your facility’s motor fleet.

The impact of voltage variation on motor performance

  • February 2014
  • Number of views: 1301
  • Article rating: No rating

The three-phase squirrel cage induction motor is a very robust machine that can operate over a wide range of voltage conditions; it is the workhorse of the industry. However, for optimum performance and life expectancy, the voltage supply should be a balanced three-phase, sine-wave voltage, and its magnitude should be as close to the nominal voltage stated on the motor nameplate as practical. 

Any deviations from these conditions may cause a depreciation in the motor performance and expected life, and increase energy costs. Benchmarking the service entry voltage and the motor performance may be a useful tool to assist in knowing when reasonable limits have been exceeded and that corrective action needs to be taken. 

The following detrimental conditions may alone or in combination exist at various times or continuously: 

  1. Voltage variation (+/- nominal)
  2. Voltage Unbalance
  3. Transient voltage (surges)
  4. Voltage waveform distortion (harmonics)

Effect of voltage variation on induction motor characteristics

  • February 2011
  • Number of views: 2502
  • Article rating: 4.5

What is voltage variation? Voltage variation is the deviation of voltage from the rated voltage; NEMA MG1 Section 12 allows a plus or minus 10% variation from rated voltage. That rating assumes balanced voltages and acknowledges that motor performance will not necessarily be the same as at rated voltage. "Table 1: Typical effects of voltage change" explains numerically the relationships between various motor performance parameters and a dynamic power supply subject to variation. It was featured in a paper by P. Pillay at an IEEE Petroleum and Chemical Industry Committee (PCIC) conference in 1995 and is shown on Page 24 in EASA's Electrical Engineering Pocket Handbook. The table was a subject of discussion at the recent meeting of the EASA Technical Services Committee in St. Louis. One purpose of this article is to better utilize the information in this table.

The effects of high or low voltage on the performance of a motor

  • August 2000
  • Number of views: 1333
  • Article rating: No rating

There is usually no problem with frequency variation, unless we get into operating at 50 Hz, but that would be an article all by itself, so the focus here will be on voltage variation only. Even though NEMA states that motors are designed to operate within 10 percent of rated voltage, that doesn't give an accurate picture of what will happen when a motor is operated with high or low voltage. Any change from the rated voltage and frequency will affect the performance of the motor, sometimes dramatically.

Getting The Most From Your Electric Motors

Getting The Most From Your Electric Motors - coverThis 40-page booklet provides great advice for obtaining the longest, most efficient and cost-effective operation from general and definite purpose electric motors.

This booklet covers topics such as:

  • Installation, startup and baseline information
  • Operational monitoring and maintenance
  • Motor and baseline installation data
  • How to read a motor nameplate
  • Motor storage recommendations



EASA/AEMT Rewind Study

EASA Rewind Study cover

The Effect of Repair/Rewinding on Premium Efficiency/IE3 Motors
Tests prove Premium Efficiency/IE3 Motors can be rewound without degrading efficiency.


ANSI/EASA AR100-2020

ANSI/EASA AR100-2015 cover

Recommended Practice for the Repair of Rotating Electrical Apparatus
This is a must-have guide to the repair of rotating electrical machines. Its purpose is to establish recommended practices in each step of the rotating electrical apparatus rewinding and rebuilding processes.



EASA Technical Manual

EASA Technical Manual cover

Revised May 2021
The EASA Technical Manual is the association's definitive and most complete publication. It's available FREE to members in an online format. Members can also download PDFs of the entire manual or individual sections.