14. PTC Fuse for DC Motor Stall Protection

When a DC motor stalls (mechanical jam), it draws several times its normal current — continuously. This sustained overcurrent can burn the motor windings, overheat the driver IC, and damage PCB traces.

A PTC fuse in series with the motor supply trips during sustained stall current but holds during normal running. When the jam is cleared and the motor restarts, the PTC cools and resets.

Hold Current Selection:

Normal current = 1.5A. With ~25% thermal derating margin: Ih range = 1.85A to 2.5A. Trip current (~2× Ih) would be 3.7A–5A, which catches a 5A stall condition.

Required: Polymeric · Ih 1.85–2.5A · ≥16V · Imax ≥10A · Through Hole · Littelfuse

Go to DigiKey.com → Circuit Protection → PTC Resettable Fuses

Apply these filters:

• Current - Hold (Ih) → 1.85A to 2.5A range
• Voltage - Max → 16V or higher
• Mounting Type → Through Hole
• Manufacturer → Littelfuse Inc.
• Part Status → Active

Important: PTC fuses have a response time of seconds — they are NOT fast-acting. For motor stall protection this is acceptable because the stall condition is sustained. For fast short-circuit protection, use a regular fuse upstream.

The filtered list will show matching parts. Before you pick one, check: Is it Active? Is stock available? Is the manufacturer reputable? Is a datasheet available?

Full checklist: How to Select a Safe, Production-Ready Component — EWskills Guide

➡ View Matching Parts — Littelfuse, PTC, Ih 1.85–2.5A, ≥16V, Through Hole