The purpose of a tap changer is to regulate the output voltage of a transformer by altering the number of turns in one winding and thus changing the turns ratio of the transformer. There are two types of tap changers: a de-energized (off-load) tap changer and an energized (on-load) tap changer. (more…)
Flow is an essential measurement in many industrial processes. In the typical application, a flow sensor is used to determine the volume of liquid or gas that passes thru a pipe, in liters/sec, GPM or similar units. Modern sensors incorporate electronics that can correct for varying pressure, temperature, density, non-linearities, and the characteristics of the fluid. These sensors may provide a local readout but usually will also send a signal to a remote indicator or SCADA system. (more…)
Isolating the measuring instrument from other circuits and earth is a simple task when using an analog meter. Most analog meters have two terminals to connect the input and no other circuit connections. The plastic case provides an insulation barrier to the metal panel or cabinet, which is tied to earth for safety. (more…)
This year’s international HydroVision Conference took place the second week of July in Denver CO. HydroVision International is the largest worldwide gathering of hydropower professionals, for informative hydropower focused meetings, seminars, tours and informal exchanges. With support from host utilities Denver Water and Xcel Energy, over 60 presentations were made by the Bureau of Reclamation, EDF Hydro, Ontario Power Generation, and others involved in this eco-friendly industry. (more…)
As the cost of energy escalates, an important issue for many businesses is how to monitor power consumption – for a device, a process, a department or an entire facility. This is typically done with a power meter or energy meter. Before we explore various instruments available for this, a quick review of basic power system parameters is warranted. (more…)