Electric motors have had a huge impact on the pump industry.
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Improved motor starters help Fabri-Kal achieve its green vision.
When a motor fails, users can (1) rewind, possibly for high efficiency; (2) replace the failed motor with a new motor; or (3) invest in a premium efficiency product. Here are the advantages and disadvantages of each approach and the precautions that must be taken to assure the best investment.
The U.S. has not enacted a wide-reaching, industrial energy efficiency bill since 1992 when the Energy Efficiency Policy Act was passed. This mandated that most general-purpose AC induction motors of 1 through 200 horsepower were required to be built to energy efficient levels per NEMA MG 1, Table 12-11 as of October 1997.
After spending money on a powerful new pump and the motor to run it, the next big decision is how to connect the two in a way that maximizes their efficiencies and protects them from normal wear and tear.
In the past year, the rate of acceleration in the cost of raw materials (including steel, iron ore, copper and aluminum) has reached unprecedented levels in the pump and rotating equipment industries.
In many pump installations, problems such as jams and suction loss can lead to serious damage to the motor or pump long before the thermal overloads trip. These problems can be quickly detected by monitoring drive motor current.
Editor's Note: Click here to see a sample alignment data form.
Proper alignment of the pump shaft with the driver can reduce vibration and significantly improve reliability. For appropriate applications, the time, expertise and instruments needed to achieve precision alignment (tolerances of less than 0.005 in) will prevent seal leakage and extend bearing life.
Latest Motors Articles
Electric motors have had a huge impact on the pump industry.
Improved motor starters help Fabri-Kal achieve its green vision.
Editor's Note: Click here to see a sample alignment data form.
Proper alignment of the pump shaft with the driver can reduce vibration and significantly improve reliability. For appropriate applications, the time, expertise and instruments needed to achieve precision alignment (tolerances of less than 0.005 in) will prevent seal leakage and extend bearing life.
As a follow up on my AC Motors series, I thought it would be a good idea to provide a short overview of work, power and torque as it applies to the AC motor. I will provide a reference to a more in depth study at the end of this article.
Mechanically generated sparks, electrostatic discharge and high surface temperatures are all potential ignition sources in explosive atmospheres. Flexible couplings play a significant role in creating and/or eliminating these explosion hazards. Consequently, the European ATEX directive applies to couplings, and for good reason.
When a motor fails, users can (1) rewind, possibly for high efficiency; (2) replace the failed motor with a new motor; or (3) invest in a premium efficiency product. Here are the advantages and disadvantages of each approach and the precautions that must be taken to assure the best investment.
Mechanical resonance occurs when an external source amplifies the vibration level of a mass or structure at its natural frequency. For a rotating mass like a motor or a pump, this occurs at the critical speed(s). Electrical resonance amplifies the magnitude of voltage or current, or both.
The Energy Independence and Security Act of 2007 (EISA), which restates and broadens the definition of General Purpose Electric Motors, goes into effect on December 19, 2010. Certain motors "manufactured (alone or as a component of another piece of equipment)" will be required to have nominal full load efficiencies that meet the levels defined in NEMA MG-1 (2006) (see Table 12-12). Motors manufactured after December 19, 2010, must comply with the law.
A large wastewater processing plant experienced continual problems with its influent raw wastewater pumps for several years. These pumps are rated at 70,000-gpm, 24-ft head and driven by 500-hp, 4000-V, 225-rpm Westinghouse brushless synchronous motors, 57.5-amps steady state rated current.
Columns and Blogs
In this multi-part series, we will investigate several aspects of centrifugal pump efficiency.
First of Five Parts
Since the original publication of this draft standard in the January 2008 issue of Pumps & Systems, I have received feedback, encouragement, numerous questions and criticism. The draft listed three basic levels of repair.
The McGraw-Hill scientific dictionary [5] states that a volute is "a spiral casing for a centrifugal pump... designed so that speed will be converted to pressure."
