June 2008 Issue

Traditionally, the primary use of drives has been in applications such as powering pumps, fans and conveyors. While they will continue to be used in these applications, today's end-users have a different approach from that of a decade ago.
Due to the expense and labor required, most facilities need to maximize the life of their motors.
Due to the expense and labor required, most facilities need to maximize the life of their motors. Electrical, insulation resistance and thermal measurement are three tests that can troubleshoot motors, drives and associ­ated electrical panels and prolong their operational lifetime. Ther­mal imagers can detect potential problems and insulation resistance and electrical tests can deter­mine the cause.
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.
In June, 2007, a reader asked Electrical Apparatus magazine, "How long should motor bearings last?" The answer will astound you.
An argument in favor of IEEE-841's provision for motor bearing protection.
Positive Displacement (PD) pump world, subdivided into pumps that operate on the linear motion principle (pistons, for example), or rotary motion, such as gear and lobe pumps.
The minimum required bolt load divided by the number of bolts in the flange will determine the minimum f, or force, needed to use the torque equation.
With sensor-equipped electrical submersible pumps, downtime can be minimized, unplanned costs can be eliminated and production optimized.
Learn about proper equipment balance in order to cut down on vibration which effects reliability, performance and uses unnecessary money. pump maintenance.
While driving a car with the gas pedal to the floor and then controlling your speed using the brake is obviously inefficient, many facilities use the approach for pump control. Flow control with throt­tling or restrictive devices sacrifices energy efficiency and results in unnecessary costs. However, with an understanding of basic principles, an analysis of the specific application, information about available control solutions and evaluation of technologically advanced equipment, facilities can make a quantum leap in improving the efficiency and econ­omy of pumping operations. pump efficiency
Owing partly to tradition, the shafts of electric motors are often larger than those of the equipment they drive.
Bigger is better — or at least it used to be
How a petrochemical pump user utilized the capabilities of a competent pump repair shop to achieve a cost-effective solution for their plant expansion.
The rotary lobe pump belongs to the positive displacement pump family.
This two-part column addresses two major causes of premature pump and motor failure.
It is impossible to balance line-to-line voltages perfectly in a three-phase circuit.
It is impossible to balance line-to-line voltages perfectly in a three-phase circuit.
A Guide to Improved Energy Efficiency, Reliability, and Profitability, written by pump systems experts. This new guidebook continues the mission of Pump Systems Matter (PSM) and the Hydraulic Institute (HI) to advance knowledge on pumping systems.
PWM inverters introduce motor shaft voltages and bearing currents. The bearing damage in inverter-driven motors is mainly caused by the shaft voltage and bearing currents created by the common-mode voltage and its sharp edges [1]. All inverters generate common-mode voltages relative to the power source ground that cause coupling currents through the parasitic capacitances inside the motor. The main source of bearing currents is the capacitance-coupling currents that return via the motor bearings back to the ground.
ePTFE /Graphite packing tolerates a wide range of service conditions and has the capabilities inherent in PTFE while overcoming limitations of low thermal conductivity. These characteristics of ePTFE enable standardization of packing to simplify operations and improve productivity in many cases.

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