Adams & Westlake Adlake 1101-87-4 Mercury Load Relay 115V Coil 50A 115V 30A 230V

Adams & Westlake Adlake 1101-87-4 Mercury Load Relay 115V Coil 50A 115V 30A 230V

The Adams & Westlake (Adlake) 1101-87-4 is a single-phase mercury load relay with a 115V AC coil rated at 50/60 Hz. It features normally open contacts and is rated for 50 amps at 115V AC and 30 amps at 230V AC, both at 3 HP on a single-phase circuit. The unit is mounted on a flat metal base plate and includes pre-attached lead wires with a ring-lug terminal on one end.

Specifications & What's Included

• Manufacturer: The Adams & Westlake Co., Elkhart, Indiana
• Trade name: Adlake Load Relay
• Catalog / Part Number: 1101-87-4
• Coil voltage: 115V AC, 50/60 Hz
• Contact configuration: Normally Open (NOR. OPEN)
• Phase: Single phase
• Contact rating @ 115V AC: 50 amps / 3 HP
• Contact rating @ 230V AC: 30 amps / 3 HP
• Mounting: Metal base plate with mounting holes
• Lead wires: Pre-attached; one ring-lug terminal, one bare/stripped end — see photos

Applications

Mercury load relays of this type were used extensively in industrial and commercial control circuits from the mid-20th century onward, particularly where silent, vibration-free switching was required. Unlike conventional electromechanical contactors, mercury relays use a sealed pool of liquid mercury to make and break the circuit, producing virtually no audible click — an advantage in noise-sensitive environments such as laboratories, offices, and HVAC control panels. The Adlake series from Adams & Westlake was a well-regarded line of these devices, commonly found in heating and cooling systems, lighting controls, motor starters, and general-purpose industrial switching applications. At 50A/115V and 30A/230V single-phase, this relay is suited to moderate motor and resistive load control. Mercury relays of this era are now largely obsolete in new installations due to environmental regulations around mercury, but they remain in service in legacy industrial and HVAC equipment and are sought by maintenance technicians and hobbyists restoring vintage machinery.