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DO Supply is a global leader in replacement parts for industrial automation equipment. Our mission is to elevate the standard of expert support, speed, and reliability for your need-it-now automation replacement and repair needs. Whether it's PLCs, drives, motors, HMIs, or more, you can count on us for the best service and fastest solutions.
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Every soft starter rating is based on a defined set of assumptions about ambient conditions, and those assumptions no longer hold once conditions change and the rated current can no longer be taken at face value. Specifying engineers and maintenance staff need to understand how ambient conditions interact with a soft starter’s thermal and dielectric limits in order to avoid nuisance trips, accelerated part wear, and outright failure. Manufacturer data from ABB, Siemens, Schneider Electric, and Rockwell Automation all point to the same underlying truth: a soft starter’s nameplate rating is a starting point, not a guarantee, once temperature, altitude, humidity, contamination, or vibration depart from standard test conditions. Understanding these factors is essential for correctly sizing and installing a soft starter in real-world operating environments. A soft starter’s current rating is assessed at a reference temperature; typically, this is 40 degrees C. This figure reflects the...
Industrial automation systems rely on industry-grade Ethernet switches to provide reliable communication among Variable Frequency Drives (VFDs), Programmable Logic Controllers (PLCs), remote I/O modules, HMIs (Human-Machine Interfaces), and other networked devices. Selecting the right Ethernet switch is a key consideration when designing, upgrading, or expanding an industrial network. Industrial Ethernet switches are primarily classified as unmanaged or managed. Unmanaged switches require no configuration and generally provide basic plug-and-play connectivity. These switches are used in small, basic networks that do not need redundancy, traffic control, advanced monitoring, or diagnostic capabilities. Conversely, managed Ethernet switches offer control over network functionality, providing greater visibility. They also support diagnostic protocols, including the Simple Network Management Protocol (SNMP). In addition, various managed Ethernet switch models do support access control...
A voltage sag on the incoming AC line may seem like a minor issue with little effect on your drive, but this isn’t always true. Every frequency inverter has a DC bus that briefly absorbs fluctuations, deciding whether the sag causes a trip, an alarm, or lets the drive ride through the event. This article covers each part of that process, drawing on Schneider Electric’s insight into where the DC bus voltage comes from, and explains the internal chain from rectifier to DC bus and its protection, with examples of products offering this capability. A Diagram of Voltage Sag A rectifier converts incoming three-phase AC to DC and charges the capacitors on the DC bus . For a typical diode-rectifier drive, the DC bus is roughly 1.35–1.41 times the RMS line voltage, depending on drive design and operating conditions. So where the input voltage is normally 480 V, the DC bus would read around 677 V. This lines up with figures quoted by Schneider Electric, who state that a 480V system has an...