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GENERAL INFORMATION - MDI Mercury Relays

MDI Mercury Displacement Relays are all designed and built to meet the most exacting demands of industry. They have won their high place in the electrical field by doing the tough and tricky jobs that ordinary equipment could at best do in an uncertain manner. They have proved their ability to stand up under the most adverse conditions of temperature, dust and moisture, in all types of applications. All the care required for the manufacture of high-grade instruments is used in the manufacture of the switches. All switch parts are specially cleaned, and contamination is avoided by use of tweezers, gloves, etc., when making assemblies.

Mercury Contactors are hermetically sealed with high quality glass to metal seals.

The stainless steel tube is totally encapsulated in high grade UL approved epoxy to prevent moisture damage and voltage breakdown through the protective coating.

The coils are wound on compact nylon bobbins and molded onto the metal tube to provide minimum power loss. This allows for low coil power required to actuate the contactor. This also enables the units to handle high loads with minimum derating due to higher ambient temperatures.

Inert gases internally prevent excessive arcing between the mercury and the electrodes which enables the unit to function for millions of cycles with very low contact resistance, and minimum deterioration of the internal parts.

Available in all standard coil voltages, in single, two and three pole arrangements. Other coil voltages available upon request.

In multiple pole units each tube is actuated by its own coil. This eliminates pull-in variation between contact tubes, assuring consistent switching.

FEATURES - MDI Mercury Relays

1) ADVANTAGES OVER ELECTROMECHANICAL AND SOLID STATE RELAYS
A) Superior Performance and Reliability
(a) Long life
(b) Durable
B) Compact Size
C) Low, Predictable Contact Resistance
D) Reduced RFI for Improved Interface Capability
E) Handles a Variety of Loads
(a) Increases design flexibility
F) Rapid On-Off Cycling Capability
(a) Mercury quickly dissipates contact heat
G) Low Coil Power Requirementsv H) Minimal Derating Due to Higher Ambient Temperatures
I) Quiet Action

2) DESIGN & CONSTRUCTION
A) Contacts are within a hermetically sealed steel body
(a) Impervious to adverse conditions
(b) No external arcing
B) Arcing is in a gaseous atmosphere
(a) Quenches the arc
(b) Extends relay life
C) Only one moving part (the plunger)
(a) No buttons to pit, weld or burn out
D) One coil for each set of contacts
(a) Assures consistent switching
(b) Minimizes pull-in variation between contacts
E) Epoxy encapsulated
(a) Moisture resistant
(b) High dielectric strength
(c) Permanently fixes contacts to coil; eliminating possible misalignment
(d) Helps dissipate heat and noise
(e) Rugged (impact resistant)

3) BENEFITS

A) Reduction of Operational and Maintenance costs
B) Increases Utilization and Productivity of Equipment
(a) By reducing down-time
C) Installation and service is a routine operation
(a) Simple to install
(b) No sophisticated equipment is required
(c) Easy to trouble-shoot