Schneider Electric B40 Thermal Overload Relay

Description:

The Square D B40 Thermal Overload Relay Heater Element Unit is a calibrated motor protection component used in Square D thermal overload relay systems. It provides overload protection by converting motor current into heat, which acts on a bimetal or melting alloy mechanism to trip the relay when sustained overcurrent conditions occur.

Applications:

The Square D B40 heater element is used in Square D motor starters and overload relay assemblies for industrial motor protection applications including conveyors, pumps, compressors, HVAC systems, and heavy machinery. It is commonly installed in motor control centers (MCCs), OEM control panels, and industrial automation systems where accurate thermal protection is required to match motor full-load current ratings.

Technical Specifications:

• Manufacturer: Square D (Schneider Electric)
• Model: B40
• Product Type: Thermal Overload Relay Heater Element Unit
• Full Load Current Range: 21.8 – 29.0 A (typical calibration range depending on relay frame)
• Trip Class: Class 20 thermal protection system
• Overload Type: Melting alloy / bimetal thermal sensing element
• Mounting Type: Plug-in heater element for overload relay base
• Function: Motor overload protection via time-delayed thermal trip mechanism
• Compatibility: Square D Type B / Type S overload relay frames
• Application Environment: Industrial motor control systems and MCC assemblies

Common Replacements:

• Square D B39 Thermal Heater Element
• Schneider Electric LRD Series Thermal Units
• Siemens 3RU11 Thermal Overload Heater Elements