Schneider Electric B7.70 Thermal Overload Relay Heater Element

Description:

The Square D B7.70 Thermal Overload Relay Heater Element is a plug-in thermal sensing unit used in motor protection systems to provide calibrated overload protection. It works by heating a bimetallic mechanism inside the overload relay, causing it to trip when current exceeds the preset range over time, protecting the motor from overheating and damage.

Applications:

The Square D B7.70 heater element is used in Square D motor starters and thermal overload relays for industrial motors, conveyor systems, pumps, compressors, and manufacturing machinery. It is commonly installed in motor control centers (MCCs), OEM control panels, and industrial automation systems where precise motor overload protection is required based on full-load current calibration.

Technical Specifications:

• Manufacturer: Square D (Schneider Electric)
• Model: B7.70
• Product Type: Thermal Overload Relay Heater Element
• Full Load Current Range: 4.93–6.27 A (typical calibration range for this unit)
• Trip Class: Class 20
• Overload Type: Melting alloy / thermal sensing element
• Mounting Type: Plug-in heater unit for overload relay base
• Function: Motor overload protection via thermal expansion/trip mechanism
• Compatibility: Square D Type B / Type S overload relay frames
• Application Voltage: Not directly rated (current-sensing element)
• Operating Environment: Industrial motor control systems

Common Replacements:

• Square D B7.71 Thermal Heater Element
• Schneider Electric LRD series heater elements
• Siemens 3RU overload heater units