Tuesday, May 12, 2009

Mercury Contactors or Mercury Displacement Relays

Mercury contactors are a great way to switch industrial loads on and off.  Mercury contactors or MDR's (Mercury Displacement Relays) can be the best option for electric heating elements.  The Mercury relays have very long life, millions of cycles, are quiet and can be cycled up to once every second.  Mercury Relays far outlast and out perform mechanical contactors and relays which can have only 100,000 cycles and be limited to switching once every 30 to 60 seconds.  Normally closed mercury relays are also used for traffic control to control blinking lights as they have the long life and higher temperature resistance  than other types of contactors, especially solid state relays.

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.

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
  1. ADVANTAGES OVER ELECTROMECHANICAL AND SOLID STATE RELAYS
    1. Superior Performance and Reliability
      1. Long life
      2. Durable
    2. Compact Size
    3. Low, Predictable Contact Resistance
    4. Reduced RFI for Improved Interface Capability
    5. Handles a Variety of Loads
      1. Increases design flexibility
    6. Rapid On-Off Cycling Capability
      1. Mercury quickly dissipates contact heat
    7. Low Coil Power Requirements
    8. Minimal Derating Due to Higher Ambient Temperatures
    9. Quiet Action
  2. DESIGN & CONSTRUCTION
    1. Contacts are within a hermetically sealed steel body
      1. Impervious to adverse conditions
      2. No external arcing
    2. Arcing is in a gaseous atmosphere
      1. Quenches the arc
      2. Extends relay life
    3. Only one moving part (the plunger)
      1. No buttons to pit, weld or burn out
    4. One coil for each set of contacts
      1. Assures consistent switching
      2. Minimizes pull-in variation between contacts
    5. Epoxy encapsulated
      1. Moisture resistant
      2. High dielectric strength
      3. Permanently fixes contacts to coil; eliminating possible misalignment
      4. Helps dissipate heat and noise
      5. Rugged (impact resistant)
  3. BENEFITS
    1. Reduction of Operational and Maintenance costs
    2. Increases Utilization and Productivity of Equipment
      1. By reducing down-time
    3. Installation and service is a routine operation
      1. Simple to install
      2. No sophisticated equipment is required
      3. Easy to trouble-shoot


      TYPICAL APPLICATIONS
      FOR MDI's MERCURY DISPLACEMENT CONTACTORS


      LIGHTING

      Auditorium Lighting
      Copy Equipment
      Dimmer Controls
      Display Signs
      Emergency Lighting
      Flood Lights
      High Intensity Lamps
      Hospital Lighting
      Lighting Test Panels
      Mercury Vapor Lamps
      Parking Lots
      Photography Lighting
      Scoreboards
      Sodium Vapor Lamps
      Stage Lighting
      Street Lighting
      Tower Control
      Traffic Signal
      Tungsten Lamps
      GENERAL APPLICATIONS

      Air Conditioning
      Alarm Systems
      Automatic Door Closers
      Battery Chargers
      Blue Print Machines
      Copiers
      Computer Power Supplies
      Corrosive Locations
      Dusty, Oily Locations
      Dry Cleaning Equipment
      Energy Management Systems
      Farm Incubators & Brooders
      High Cycle Rate Applications
      Low Voltage Switching
      Marking & Engraving Equipment
      Motor Starting
      Soldering Systems
      Telephone Switching
      Test Panels
      Vapor Degreasers
      X-Ray Machine Controls
      ELECTRIC HEATERS

      Baseboard Heaters
      Blow Molding
      Cabinet Heaters
      Chemical Tank Heaters
      Curing Furnaces
      Drying Ovens
      Duct Heaters
      Film Packaging
      Glass Furnaces
      Heat Lamps
      Heat Sealing Machines
      Induction Heater
      Industrial Ovens
      Infrared Heaters
      Ink Drying
      Ink Heating
      Injection Molding Machines
      Kilns
      Lab Ovens
      Packaging Equipment
      Plastic Extruders
      Quartz Heaters
      Radiant Heaters
      Roof Top Heating
      Shrink Tunnels
      Unit Heaters
      Vacuum Forming



      FOOD INDUSTRY EQUIPMENT
      (HEATERS)


      Baking Ovens
      Coffee Urns
      Deep Fryers
      Dishwashers
      Electric Grills
      Electric Ranges
      Pizza Ovens
      Steam Generators
      SPECIALTY APPLICATIONS


      Capacitor Discharge Systems
      Hazardous Locations
      Phase Converters
      Tower Control





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