ONPOW releases technical guidance on micro switch travel specifications
ONPOW has outlined standard practices for interpreting micro switch travel terms to ensure reliable mechanical integration in industrial systems.
Understanding the mechanical travel of micro switches is essential for ensuring precise system performance. ONPOW has clarified the definitions of pretravel, overtravel, and differential movement, noting that these parameters must be calculated within a consistent coordinate system rather than estimated visually.
Pretravel refers to the movement from the free position to the point of contact closure. Overtravel, the movement allowed beyond that point, provides essential installation tolerance. ONPOW cautions designers against using a switch’s internal mechanism as a physical machine stop, as this risks structural damage and failure. Proper mechanical limiters should always manage the total path of the actuator.
Differential movement—the hysteresis between operating and release positions—often causes confusion during system testing. ONPOW notes that the contact state depends on the direction of movement, meaning a switch may remain active even after slight withdrawal. Engineers are advised to verify these specifications against specific mounting tolerances to avoid unpredictable switching behavior.