Tag: June 2007 Issue
These items have all been tagged with the tag "June 2007 Issue", You can see other tags in the Tag CloudAlmost everyone has experienced the process of buying a car. There are many choices - new or used, economy or luxury, RWD or AWD, manufacturer's reputation and service - the list goes on. We weigh the choice between price and longevity, cost to maintain, etc. in making our decision. The research and understanding of other's experiences, specifications and financing related to the decision can make the difference between a great experience and an expensive disappointment.
Pumps & Systems, July 2007
Last month we took a close look at the flow of voltage and current in purely resistive and inductive circuits. We showed how inductive reactance can inhibit the flow of primary current in a circuit and how this lagging effect determines the value of power factor (PF).
Although the purely resistive and inductive examples we used helped us understand what was happening, they do not represent a typical electrical circuit. Almost all circuits are a combination of resistive and inductive loads and, in some cases, those that are capacitive as well. Motors, arc welders, transformers, heaters, incandescent lighting, ballast lighting, solid state power supplies, and many other electrical devices contribute to the overall load on the circuit.
Pumps & Systems, June 2007
Most of the electric motor information we use on a daily basis is pretty straightforward. Voltage, amps, efficiency, and service factor are all well understood terms in our industry. There is, however, one motor characteristic that can be anything but straightforward. That characteristic is power factor (PF).
Pumps & Systems, June 2007
Last month, we discussed applications of low head axial flow pumps ("Field Testing: Theory vs. Reality," Pumping Prescriptions, May 2007). Knowing your system is very important for these types of units. For example, consider a recent application where neglecting the system caused problems.
Pumps & Systems, June 2007
The globalization wave, outsourcing surge and the sizzling economies in Asia-Pacific - particularly India and China - create an attractive picture for investments in the pumps market. With its seemingly limitless supply of low manufacturing cost benefits and the favorable investment climate, the Asia-Pacific region has an immeasurable amount of potential.
Pumps & Systems, June 2007
Shaft failures do not happen everyday, but when they do, it can be a challenge to determine the cause of failure. Here's a technical explanation of what happens when the shaft bends or breaks.
Pumps & Systems, June 2007
Named for a technique commonly used on failing pumps, "percussion maintenance" - where a technician beats on the pump's stalled motor with a hammer or rubber mallet - often indicates motor deficiencies in his diaphragm pump. Though it is impossible for the maintenance department to predict when a pump will stall, such maintenance techniques are often the result of poor motor design.
Pumps & Systems, June 2007
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.
Pumps & Systems, June 2007
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.
Pumps & Systems, June 2007
Cavitation is a destructive condition that can destroy the inside of a pump before you even realize it is occurring. Early detection can minimize damage, reduce downtime, and save money. Cavitation involves the creation of bubbles formed when the fluid being pumped vaporizes due to a decrease in pressure as the fluid enters the pump. These bubbles are then acted on by the pump impeller, causing them to implode.
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