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Variable Speed Drive Measurements using the DI-730 Data Acquisition System

Variable Speed Drive Measurements

Motors using variable speed drives are found at virtually all levels of production, from mining raw materials and processing them into finished goods, to transporting those to market. Examples include open pit mining machines, steel and steel rolling mills, aluminum rolling mills, paper mills, heavy duty cranes, heavy duty construction equipment, electric locomotion by rail and sea, and high speed transit cars. In these applications and many more, the costs associated with system down time caused by a motor or drive failure can be severe. For this reason motor and drive maintenance and troubleshooting is a major activity in many industries, and our DI-730 is the first PC-based product designed specifically for these and other demanding measurements that require isolation and wide dynamic range.

The following diagram shows a variety of typical measurements made by our customers every day on variable speed drives using our model DI-730 data acquisition hardware. Each represents a direct-connected measurement without applying external isolators, dividers, or amplifiers.

Variable Speed Drive Measurements

Symbol Descriptions (direct connections to the DI-730)
Symbol Description Method Typical Voltage Range Typical Calibrated Range
VIA Armature Current Shunt ±100 mV 100-2000 A
VA Armature Voltage Direct 0-500 V 0-500 V
VIF Field Current Shunt 10-50 mV 0-20 A
VF Field Voltage Direct 0-300 V 0-300 V
VR Speed Reference Direct 0-10 V 0-4000 RPM
VT Tachometer Direct* 0-200 V* 0-4000 RPM
*May also be acquired as a pulse train with frequency proportional to RPM.

See the DI-730 Main Page for more information

Variable Speed Drive MeasurementsDownload the Datasheet for product specs, options, accessories, and applications. Variable Speed Drive MeasurementsDownload the white paper: "Solutions for Electromechanical Maintenance and Troubleshooting."

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Typical Applications for Variable Speed Drive Measurements

Variable Speed Drive Measurements for Winders/Coilers
Marine Applications
Variable Speed Drive Measurements for Marine Applications
Variable Speed Drive Measurements for Cranes/Hoists
Variable Speed Drive Measurements for Mining and Drilling Applications
Variable Speed Drive Measurements for Extruding Applications

Additional reading:

Synchronized and Distributed Data Acquisition Using DI-720/DI-730 Instruments in Hot Strip Steel Mills
Pressure and Flow Data Acquisition Measurements in Hydraulic Systems