Power quality problems are among the most common barriers to smooth running motors and drives and thus, a smooth-running facility. While there are countless common power quality related issues, the two problems discussed here are motor overload and harmonics.
Motor overload is a consequence of a motor that is under excessive load. The main symptoms of motor overload are overheating, insufficient torque, and excessive current draw. Premature wear on electrical and mechanical components is caused by excessive motor heat, a situation that ultimately leads to complete motor failure. In the case of an overloaded motor, individual motor components including bearings, motor windings, and other components may be working fine, but the motor will continue to run hot. Diagnosing motor overload with a power quality analyzer can extend motor life, reducing failure, downtime and economic loss.
Harmonics are any unwanted additional source of high frequency ac voltages or currents supplying energy to the motor windings. Harmonics decrease motor efficiency, resulting in added cost and an increase in operating temperatures. This additional energy is not used to turn the motor shaft, but circulates in the windings and ultimately contributes to internal energy losses. These losses dissipate in the form of heat which, over time, will deteriorate the insulation capability of the windings. Some harmonic distortion of the current is normal on any part of the system serving electronic loads.
Electricians and technicians will want to safely investigate with a digital multimeter. When checking for harmonics or diagnosing motor overload, it is recommended that technicians use a power quality and motor analyzer