Electric motors have had a huge impact on the pump industry.
Topic Sponsor
Top Motors Articles
Improved motor starters help Fabri-Kal achieve its green vision.
For the first time, the United States Department of Energy (DOE) adopted energy conservation standards for small electric motors in February 2010. DOE determined these standards will result in significant conservation of energy, and are technologically feasible and economically justified. Motors covered under these new regulations range from ¼ to 3 hp and include single and poly phase two, four and six pole general purpose motors in NEMA 42, 48 and 56 frames and corresponding IEC equivalent motors and frames. The new regulations will take effect in 2015, which is five years after the original publish date.
It is impossible to balance line-to-line voltages perfectly in a three-phase circuit. In fact, line voltages typically differ by a few volts or more, but a difference that exceeds 1 percent can lead to serious trouble on the plant floor. To maintain peak energy efficiency and thwart premature failure of three-phase motors, install adequate protective devices and periodically check for voltage unbalance at the motor terminals.
Because operational costs ride on efficiency determinations, accurate measurements of losses occurring within the motor are paramount. The reliability of efficiency data is key to any energy-savings plan, and knowing the meaning behind the rating can make or break a smart purchasing decision.
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.
Introduced in June 2010, Super-E Motors with AEGIS Shaft Grounding Ring are used in commercial and industrial applications to drive pumps provides a path to ground for circulating currents, preventing bearing fluting.
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.
Latest Motors Articles
Electric motors have had a huge impact on the pump industry.
Improved motor starters help Fabri-Kal achieve its green vision.
The global economic downturn has resulted in an unprecedented attempt by world governments to help stimulate their individual economies, with the hope that these combined efforts will have a cumulative effect of breaking the downward spiral and lifting the global economy out of its crisis.
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.
The freefall in electric motor sales is a direct effect of the worldwide economic downturn, which has severely depressed industrial and commercial productions. Despite the 20 to 30 percent drop in motor sales in 2009, manufacturers remain optimistic about the future market landscape, as the economic recovery, the need to improve energy efficiency and the demand in high growth sectors will create need for high performance motors.
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.
The economic downturn has delivered a heavy blow to the industrial manufacturing sector in North America. Manufacturers are indicating sales drops of 30 percent to nearly 60 percent compared to that of 2008.
Advanced motor protective relays provide superior protection for motors and pumps.
With highly reliable electrical systems, protective relays may be called upon to operate very infrequently. However, the effects of faults and abnormal conditions can be severe and protective relay systems must be designed carefully to protect against the worst possible fault conditions.
Following the development of variable frequency converter drives during the 1990s, totally enclosed fan-cooled (TEFC) AC induction motors became viable options for replacing DC motors in pumping applications. The torque and speed characteristics of these motors are a close match to those required for centrifugal pumps.
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."
