The **FTS-3B-R/BN** is a specific model within the series of **Float Type Level Switches** (often associated with manufacturers like Finetek). These devices are used to detect liquid levels in tanks or sumps to control pumps or trigger alarms. --- ## 1. Technical Specifications The "R/BN" suffix typically denotes specific material and contact configurations. Below is a breakdown of the electronic and mechanical characteristics: | Feature | Specification | | :--- | :--- | | **Contact Type** | Microswitch (SPDT - Single Pole Double Throw) | | **Contact Capacity** | 10A / 250VAC (Resistive Load) | | **Float Material** | Polypropylene (PP) or Neoprene (depending on sub-spec) | | **Cable Material** | BN (Usually High-quality Neoprene or Rubber) | | **Operating Temp** | -10°C to 80°C | | **Max Pressure** | 2 kg/cm² | --- ## 2. Internal Electronic Components The device operates on a simple but reliable electromechanical principle. It does not contain complex integrated circuits (ICs), but rather high-durability discrete components: ### A. The Microswitch The heart of the FTS-3B is a **Microswitch**. - **Function:** When the float tilts (due to rising or falling liquid), an internal weight or rolling ball moves to actuate the switch plunger. - **Wiring:** Being an SPDT switch, it provides three connection points: 1. **COM (Common)** 2. **NO (Normally Open)** - Closes when the float is up. 3. **NC (Normally Closed)** - Opens when the float is up. ### B. The Cable (BN Specification) The "BN" designation often refers to the **Chloroprene (Neoprene)** cable. - **Electronic Role:** It provides high insulation resistance and is designed to withstand continuous immersion in water or oily liquids without the outer jacket becoming brittle or leaking current. --- ## 3. Wiring Diagram Logic To integrate this into an electronic control system (like a PLC or a Motor Starter), the wiring typically follows this logic: ```mermaid graph LR A[Power Source] --> B[Common Wire] B --> C{Microswitch} C -- Float Up --> D[NO Contact -> Pump Off/Alarm On] C -- Float Down --> E[NC Contact -> Pump On/Alarm Off] ``` ### Wiring Colors (Standard) * **Blue:** Common (COM) * **Brown:** Normally Open (NO) - Closes on rise. * **Black:** Normally Closed (NC) - Opens on rise. --- ## 4. Applications - **Wastewater Management:** Controlling submersible pumps in sumps. - **Industrial Tanks:** High/Low-level alarm triggering. - **Electronic Integration:** Acting as a digital input (DI) for a PLC to manage automated filling cycles.