A “stable” curve is important for pump operation, especially for pumps in parallel operation. The higher the energy level and the more critical an installation, the more the pump curve could become an issue.
Application and maintenance of the manufacturers' recommended torque to valve packing is critical to meeting emissions requirements and long service life. While approaches to the application of torque for braided and die-formed packing may be different, the generally accepted practices are important to all valve packing. Consultation with the packing manufacturer on specifics of the application can help to ensure reliable performance.
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.
The service department of a variable frequency drives manufacturer frequently sees the following scenario: A frustrated user calls with what he perceives to be a defective piece of equipment. As the technician begins probing for information, the user's frustration boils over, often with an exclamation along the lines of "what a piece of junk!" As the service technician asks the pertinent questions, the exasperated user relays the details of a drive that is continually tripping on a fault until the user is at the end of his rope, not knowing what to do.
"How long will I be able to run my equipment before it has to be taken down for servicing?" is a question often asked when a buyer or user decides to purchase a new pump, agitator, or other type of rotating equipment.
The low voltage motors market is highly consolidated, with the top five participants accounting for more than 75 percent of the market revenues as of 2009. Low voltage alternating current (AC) motors dominate the industry, generating 92.1 percent of market revenues for 2009. That number is expected to increase to 95.9 percent by 2016, with a Combined Annual Growth Rate (CAGR) of 7.6 percent between 2006 and 2016. Low voltage direct current (DC) motors, on the other hand, are expected to have a negative 3.4 percent CAGR between those years.
The frame sizes (physical dimensions) of AC motors have changed substantially through the years. Originally, they were considerably larger than those in use today. This increased size was the result of inefficiency and the need to dissipate heat.
One of the major contributors to unbalance in rotating machinery is eccentricity. When we disassemble parts, we must also reassemble them. Even if the reassembly requires heating to shrink-fit the elements back together, we probably balanced them in a balancing machine where tolerances due to fit-up on mandrels or roundness of journals may possibly far exceed the heavy spot tolerances that the target standard of balance allows.
Gasket stress is a term commonly used to describe the unit load on its surface. It is one of the most important parameters of a bolted joint because it directly impacts the ability of the gasket to seal.