Square D B4.15 Thermal Unit Type S, Class 20, Melting Alloy, 200A Max

Description

Features

• Utilizing an ultra-reliable, eutectic melting alloy formula, this thermal unit responds to motor overload conditions by absorbing localized heat generated by excessive current. Once the precise melting temperature is reached, the alloy liquefies rapidly, instantly releasing the internal mechanism to trip the starter and save high-value industrial motor windings from catastrophic insulation degradation.
• Engineered specifically with a Class 20 timing curve, this unit provides a precise 20-second delay at 600% of its current rating before breaking the circuit. This extended window accommodates the high inrush currents and long acceleration cycles typical of heavy industrial equipment like industrial centrifuges, rock crushers, and high-inertia fans without causing annoying nuisance trips.
• Designed for seamless physical layout inside Square DTM Type S NEMA-rated starter blocks, this module offers a perfect mechanical fit. The factory-standard footprint ensures direct alignment with the overload relay block terminals, allowing maintenance electricians to drop the element in quickly and restore crucial motor protection networks without modifying backplate hardware.
• Built as a single, factory-calibrated assembly, the unit eliminates the field installation errors common with multi-piece heaters. This interchangeable design enables facility engineers to adjust or swap the starter's total overload current rating simply by changing the thermal element, simplifying inventory management and maintaining code-compliant motor branch circuit protection.

Documentation & Downloads

Specifications