LogoLogo
  • Welcome!
  • Mission Statement
  • Contributing Guidelines
    • Embed CADs in Wiki Articles
  • VEX Worlds Livestream Archive
    • VEX U
    • V5RC High School
    • V5RC Middle School
    • VIQRC Middle School
    • VIQRC Elementary School
    • JROTC
  • ⚙️Hardware
    • Design Fundamentals
      • Gear Ratios
      • Internal Forces (Stress)
      • Torque
      • RPM
      • Center of Mass
    • Introduction to VEX Parts
      • Structure
        • C-Channels and Angles
        • Fasteners
        • Retainers
        • Gussets and Brackets
        • Bearings
        • Plate Metal and Flat Bars
      • Motion
        • High Strength Components
        • Gears and Sprockets
        • Traction Wheels
        • Mecanum Wheels
        • Omnidirectional Wheels
        • Flex Wheels
    • Robot Decorations
      • Part Dyeing
      • Metal Coloring
      • License Plate Holders
    • Lifts
      • Double Reverse Four Bar (DR4B or RD4B)
      • Four Bar
      • Scissor Lift
      • Six Bar
      • Other Lifts
      • Best Practices
    • Shooting Mechanisms
      • Catapult
      • Flywheel
      • Linear Puncher
    • Drivetrains
      • Tank Drive
      • Mecanum Drive
      • Holonomic Drive
      • Designing a Drivetrain
      • Best Practices
    • Pivots & Joints
    • Pneumatics
      • Best Practices - Pneumatics
    • Intakes
    • Flip Out Mechanisms
    • Defensive Mechanisms
    • Misc. Building Techniques
    • VexU
      • Common Manufacturing Techniques
        • 3D Printing
        • Laser Cutting
      • Custom Manufactured Parts Library
      • Commercial Off The Shelf Parts Library
  • 👑Team Administration
    • New Team Resources
      • Creating The Team
      • Gaining Interest for Robotics Teams
      • Attending Competitions
        • Elimination Bracket
    • Team Dynamics
      • Organization Structure and Longevity
      • Member Allocation and Management
      • How *Not* To Run a Team
    • Team Finances
      • One-Year Team Financial Breakdown
      • Funding Your Teams
    • Hosting Competitions
      • Live Streaming
      • Tournament Manager
        • Competition Electronics
        • Creating a Tournament
        • Tools
          • Field Set Control
          • Connecting Mobile Devices
          • Connecting Raspberry Pis
        • Match Control
          • Inputting Match Scores
          • Inputting Skills Scores
          • Inputting Scores on TM Mobile
        • Displays
        • Alliance Selection
      • Additional Event Partner Resources
    • VexU Organization Management
      • Getting Started in VexU
      • Team / Personnel Management
      • Volunteering At Local Events
  • 📚The Judging Process
    • The Engineering Design Process
      • Test and Refine
    • The Engineering Notebook
      • Segments of the Notebook
      • BLRS2 '23-'24 Engineering Notebook
      • Integrating Inventor Models into Documentation
      • Engineering Notebook Rubric Breakdown
    • The Interview
      • Interview Rubric Breakdown
    • Using Notion for an Engineering Notebook
      • How to Setup a Notebook
      • How to Create Entries
      • How to Export a Notebook
      • Purdue SIGBots Notion Template
        • Game Analysis
        • Identify The Problem
        • Brainstorm Solution
        • Select Best Approach & Plan
        • Build Log
        • Programming Log
        • Testing Solution
        • Tournament Recap
        • Innovative Feature
  • 🖥️VEX CAD
    • CAD Programs
      • Inventor
      • Fusion 360
      • Solidworks
      • OnShape
      • Protobot
    • Making a Chassis
      • Inventor Chassis: The Basics
        • Installation
        • User Interface Overview
        • Dark Mode
        • Assemblies
        • Placing Parts
        • Navigating CAD
        • Changing Visual Style
        • Grounding
        • Connecting Two C-Channels
        • Modifying Existing Constraints
        • Toggling Visibility on Existing Parts
        • Completing Half of the Chassis
          • Inner Drive Channel
          • Bearing Flats
          • Motors
          • Wheels
          • Sprockets
          • Spacers, Washers and Standoffs
          • Spacers Cont.
        • Creating Mid-Plane
        • Mirroring
      • Inventor Chassis: Best Practices
        • File Structure
        • Subassemblies
        • Wheel Subassembly
        • Origin Planes
        • Cross Brace
        • Drive Channels
        • Simple Motor iMates
        • Replacing Simple Electronics
        • Completing Half of the Drive
          • Bearing Flats (Best Practice)
          • Wheels
          • Powered Gear
          • Spacer Boxing
          • Spacers, Washers and Standoffs (Best Practice)
        • Model Browser Folders
        • Mirroring (Best Practice)
        • Model Browser Folder (Right)
        • Main Assembly
      • Fusion 360 Chassis
      • Solidworks Chassis, Chain, and Custom Plastic
    • Remembering The Best
      • 62A Skyrise
      • 400X Nothing But Net
      • 2587Z Nothing But Net
      • 365X Starstruck
      • 62A In The Zone
      • 202Z In The Zone
      • 5225A In The Zone
      • 169A Turning Point
      • 929U Turning Point
      • 7K Tower Takeover
      • 5225A Tower Takeover
      • 62A Change Up
    • Scuff Controller
  • 💻Software
    • Odometry
    • Path Planning
    • Robotics Basics
      • Arcade Drive
      • Tank Drive
      • Joystick Deadzones
      • Curvature (Cheesy) Drive
      • Subsystem Toggling
    • Organizing Code
      • Code Style
      • Code Styling Guide
      • Writing Good Comments
      • Version Control
    • Control Algorithms
      • Bang Bang
      • PID Controller
      • Basic Pure Pursuit
      • Flywheel Velocity Control
      • Kalman Filter
      • Take Back Half (TBH) Controller
      • RAMSETE Controller
    • Competition Specific
      • Operator Control
      • Autonomous Control
    • C++ Basics for VEX Robotics
      • Basic Control Flow
      • Enumerations
      • Namespaces (::)
      • Multiple Files (C/C++)
    • VEX Programming Software
      • PROS
        • OkapiLib
      • vexide
      • Robot Mesh Studio (RMS)
      • EasyC
      • RobotC
      • VEXcode
      • Midnight C
    • General
      • Stall Detection
      • Register Programming
      • Sensors and Odometry in Autonomous
      • Embedded Programming Tips
      • Debugging
      • Bit Shift
      • Bit Mask
      • Autoformatting
      • Finite State Machine
      • Data Logging
    • Object Recognition
      • Red Green Buoy
      • AMS
      • OpenCV
      • OpenNI
    • 🤖AI in VRC: Pac-Man Pete
  • ⚡VEX Electronics
    • V5 ESD Protection Board
    • VEX Electronics
      • VEX V5 Brain
        • V5 Electronics Observations and Issues
      • VEX Controller
      • VEXnet and V5 Robot Radio
      • VEX Battery
      • VEX Motors
    • VEX Sensors
      • 3-Pin / ADI Sensors
        • Encoder
        • Potentiometer
        • Limit Switch
        • Bumper Switch
        • Accelerometer
        • Gyroscope
        • Ultrasonic
        • Line Tracker
        • LED Indicator
      • Smart Port Sensors
        • GPS Sensor
        • Rotation Sensor
        • Vision Sensor
        • Optical Sensor
        • Distance Sensor
        • Inertial Sensor (IMU)
        • 3-Wire Expander
    • V5 Brain Wiring Guide
    • Legacy
      • VEX Cortex
      • Power Expander
      • VEX Motor Controller
      • VEX Cortex Wiring Guide
  • General Electronics
    • General Topics
      • External Boards
        • ASUS Tinker Board S
        • Arduino
        • Beagleboard
        • Leaflabs Maple
        • LattePanda
        • Meadow F7 Micro
        • Netduino
        • ODROID-XU4
        • Pandaboard
        • Raspberry Pi
      • Analog-Digital Converter (ADC)
      • Bit-Bang
      • GPIO
      • I2C
      • Jitter
      • Line Noise
      • List of Tools
      • Output Drive
      • Power Consumption
      • Radius Array
      • Resettable Fuse (PTC)
      • SPI
      • Slew Rate
      • Stalling
      • USART
      • UART
      • 5 Volt Tolerant
      • DC Motor Basics
Powered by GitBook
LogoLogo

This work is licensed under a Attribution-ShareAlike 2.0 Generic License

On this page

Was this helpful?

Edit on GitHub
Export as PDF
  1. General Electronics
  2. General Topics

Resettable Fuse (PTC)

A resettable fuse, sometimes known as a PPTC for polymeric positive temperature coefficient, is a safety device intended to prevent excessive Power Consumption and thus overheating of an electronic de

PreviousRadius ArrayNextSPI

Last updated 3 years ago

Was this helpful?

A selection of resettable fuses similar to the types used for protection of VEX components

Resettable fuses are devices with a very low resistance when cool, so they have little effect when placed in series with a load. However, when large currents flow through the load, the fuse begins to heat up due to ohmic heating. As the temperature of the fuse increases, the resistance increases slowly. However, at a critical point, the resistance begins to increase rapidly, eventually reaching a point where the fuse develops a resistance in the many thousands of ohms, reducing the current to a safe level and disabling the load. After the current overload dies down, the fuse begins to cool and drops in resistance back to its initial value.

Since cooling occurs at a different rate than heating (black body radiation compared to ohmic heating), the fuse may take up to 30 seconds to cool down and over 5 minutes to recover fully, even though it can trip in less than a second.

are equipped with a resettable fuse (1.5 A/269, 1.8 A/393). Since the stall current of VEX Motors is much higher than the trip current, the fuse will heat up quite rapidly when running at very high power consumption rates, possibly cutting power to the motors during a match. Motors should therefore be designed to run at a point somewhat less than the maximum torque output to avoid this issue, or must be equipped with to stop the condition before it becomes a problem.

Teams Contributed to this Article:

The has a 4 A resettable fuse controlling each bank of 5 motors (1-5 and 6-10). Likewise, the has one 4 A resettable fuse for all four outputs. No more than two 2-Wire Motor 393 modules should be used simultaneously on a VEX Power Expander or per group of five motors on the VEX Cortex. Splitting heavy loads across the motor banks (e.g. plugging the left drive motors into ports 1-3 and the right drive motors into ports 7-9) will reduce the likelihood of a main fuse trip during a match.

(Purdue SIGBots)

VEX Cortex
Power Expander
BLRS
Motors
Stall Detection