Availability
Millions of parts are available for same-day shipping and next-day delivery.
Save money on downtime with the most trusted leading experts in automation replacement and repair.
Millions of parts are available for same-day shipping and next-day delivery.
45+ years of experience to help you find an ideal replacement or repair solution.
We stand behind our quality by offering a complimentary 2-Year DO Supply Warranty on all products.
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.
Shop with confidence knowing that we offer fast shipping and best-in-class customer service. Explore our large inventory of in-stock automation parts backed by the guarantee of a 2-year DO Supply Warranty.
Save money on getting your automation parts repaired for less, backed by our 2-year DO Supply Warranty. We offer quality repairs at the best prices, carried out by expert technicians.
We want to buy your industrial automation surplus equipment, including PLCs, drives, motors, HMIs, and more.
Shop a large selection of manufacturers and product lines.
Surplus Allen Bradley, GE, Fanuc, Emerson, Eaton, Mitsubishi, Omron, and more.
Discover insightful industry knowledge
The most time-consuming diagnostic issue in industrial motor control is intermittent drive faults. Production halts, the drive trips, a technician resets it, and it runs for hours before malfunctioning again under similar circumstances. Since the drive is the most visible component and is showing the failure code, it is natural to blame it. Replacing the drive instantly restores production. The issue is that most persistent drive problems can be traced to external factors, such as loose power connections, deteriorated cable insulation, mechanical binding, supply voltage disruptions, or interference from control signals. A mechanical or electrical root cause, rather than a drive malfunction, often causes intermittent drive failure under the same circumstances. Effective drive fault research starts with understanding these external sources and the diagnostic methods that separate them. In industrial installations, loose connections are the second most common cause of drive faults. Heat...
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...