The Bussmann series FRS-R-40 is an energy effcient, dual-element, time-delay Class RK5 fuse and is part of our FUSETRON line of fuses. Its dual-element design provides the best time-delay for better protection of equipment such as power panelboards, combination starters, motor control centers, machinery disconnects, and safety switches. Dual element fuses feature separate overload and short-circuit elements to provide the same short circuit protection as a fast acting fuse with the added benefit of letting inrush currents pass without opening the fuse. As a time-delay fuse, it allows for temporary overload conditions without opening (sometimes called blowing a fuse). This is necessary for equipment that regularly experiences short-term power surges, such as when a motor or transformer strarts up. The time-delay feature allows an inrush current from the motor or transformer to start without opening but still protects against sustained overloads and short circuits. This also allows you to reduce the need to replace expired due to normal inrush overloads. For superior electrical protection, we recommend upgrading to Bussmann series Low-Peak LPS-RK fuses.
Heavy duty time-delay fuse used in motor protection. When sized correctly, it helps protect motors from burnout caused by overloads or single-phasing. The time-delay feature allows the initial startup current surge for typical motors to pass, but opens prior to motor burnout when longer, dangerous overloads are present. In addition, the dual-element design opens in as little as 0.004 second if the fuse experiences short-circuit conditions. UL Listed Class R (IR: 200kA). Groove in end cap or notch in knife blade permit the fuse to be used in Class H, Class K or Class R fuse blocks. Cartridge fuses are used to protect motors and branch circuits where higher amps or volt ratings are required. They are available in a wide variety of sizes, amp and volt ratings up to 600Vac and 600 amps. Cartridge fuses are used extensively in commercial, industrial and agricultural applications as well as residential fuse panels, air conditioning, pumps, appliances and other equipment. Cartridge fuses are available in two types. General Purpose fuses have no time-delay and protect fuse panels, appliances and branch circuits. Heavy- Duty fuses have a time-delay feature, allowing momentary motor startups. Both are available in 250Vac and 600Vac versions with catalog symbol and amp rating stamped on the knife blade or end cap.