VFD protection relay
The EL731 ac/dc Sensitive Earth-Leakage Relay by Littelfuse can detect ground currents.
Littelfuse Inc.’s EL731 ac/dc Sensitive Earth-Leakage Relay can detect ground currents—even in resistance-grounded electrical systems—all the way down to 0 Hz. This makes it ideal for protecting variable-frequency drives (VFDs) that may operate at low speeds, during which ac current approaches dc. The EL731 relay provides complete range of ground-fault protection in VFDs from 0 to 15,000 Hz in one device, saving cost and panel space compared to other relays. The EL731 uses a patented approach that enables the relay to detect the location of ground faults and makes it equally useful for ac, mixed ac/dc, and dc systems, including low-voltage 6-pulse VFDs commonly used on motors up to 250 hp. The relay is ideal for protecting VFDs operating in resistance-grounded electrical systems, which are growing in popularity because of their ability to reduce arc-flash hazards. The on-board ground-fault protection that comes with VFDs is generally not sensitive enough to detect a ground fault in resistance-grounded systems.
Case Study Database
Get more exposure for your case study by uploading it to the Consulting-Specifying Engineer case study database, where end-users can identify relevant solutions and explore what the experts are doing to effectively implement a variety of technology and productivity related projects.
These case studies provide examples of how knowledgeable solution providers have used technology, processes and people to create effective and successful implementations in real-world situations. Case studies can be completed by filling out a simple online form where you can outline the project title, abstract, and full story in 1500 words or less; upload photos, videos and a logo.
Click here to visit the Case Study Database and upload your case study.