The **MDA-1-R** is a specific type of electronic fuse manufactured by **Eaton (formerly Bussmann)**. It belongs to the MDA series, which are characterized by their ceramic construction and time-delay (slow-blow) properties. --- ### ## Technical Specifications Below are the primary electrical and physical characteristics of the MDA-1-R: | Property | Specification | | :--- | :--- | | **Current Rating** | 1 Ampere | | **Voltage Rating** | 250 Vac (Standard) | | **Interrupt Rating** | 35A at 250Vac / 10,000A at 125Vac | | **Response Time** | Time-Delay (Slow-Blow) | | **Material** | Ceramic Tube, Nickel-plated Brass Endcaps | | **Physical Size** | 1/4" x 1-1/4" (6.3mm x 32mm) | | **Compliance** | RoHS Compliant (indicated by the "-R" suffix) | --- ### ### Key Components and Features 1. **Ceramic Tube Body:** Unlike glass fuses (which are transparent), the MDA-1-R uses a ceramic body. Ceramic is used because it can withstand higher temperatures and has a higher "interrupting rating," meaning it can safely break a circuit during a high-energy short circuit without the fuse body shattering. 2. **Time-Delay Element:** This part is designed to allow temporary "inrush currents." For example, when a motor or a large capacitor starts up, it may briefly draw more than 1 Amp. The MDA-1-R will not blow immediately under these brief spikes, but it will blow if a sustained overcurrent occurs. 3. **The "-R" Suffix:** In the Eaton/Bussmann catalog, the suffix **-R** stands for **RoHS Compliant**. This means the part is manufactured without lead or other hazardous substances restricted by European environmental standards. --- ### ### Common Applications The MDA-1-R is typically found in industrial and heavy-duty electronics where high breaking capacity and slow-blow characteristics are required: * **Power Supplies:** Protecting the input stage against surges. * **Industrial Control Panels:** Where small motors or solenoids are present. * **Medical Equipment:** Due to the reliability of ceramic housing. * **Test Equipment:** Protecting internal circuitry from overloads. --- ### ### Troubleshooting Note If you are replacing an MDA-1-R, ensure the replacement is also **Ceramic** and **Time-Delay**. Replacing a ceramic fuse with a glass fuse of the same amperage (like an AGC-1) can be dangerous because the glass may explode if a high-energy fault occurs that exceeds the glass's lower interrupt rating.