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.

1. ADVANTAGES OVER ELECTROMECHANICAL AND SOLID STATE RELAYS
2. 1. Superior Performance and Reliability
   2. 1. Long life
      2. Durable
   3. Compact Size
   4. Low, Predictable Contact Resistance
   5. Reduced RFI for Improved Interface Capability
   6. Handles a Variety of Loads
   7. 1. Increases design flexibility
   8. Rapid On-Off Cycling Capability
   9. 1. Mercury quickly dissipates contact heat
   10. Low Coil Power Requirements
   11. Minimal Derating Due to Higher Ambient Temperatures
   12. Quiet Action
3. DESIGN and CONSTRUCTION
4. 1. Contacts are within a hermetically sealed steel body
   2. 1. Impervious to adverse conditions
      2. No external arcing
   3. Arcing is in a gaseous atmosphere
   4. 1. Quenches the arc
      2. Extends relay life
   5. Only one moving part （the plunger）
   6. 1. No buttons to pit, weld or burn out
   7. One coil for each set of contacts
   8. 1. Assures consistent switching
      2. Minimizes pull-in variation between contacts
   9. Epoxy encapsulated
   10. 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）
5. BENEFITS
6. 1. Reduction of Operational and Maintenance costs
   2. Increases Utilization and Productivity of Equipment
   3. 1. By reducing down-time
   4. Installation and service is a routine operation
   5. 1. Simple to install
      2. No sophisticated equipment is required
      3. Easy to trouble-shoot

The load terminals are isolated from each other by the glass in the hermetic seal. "The plunger assembly", which includes the ceramic insulator, the magnetic sleeve and related parts, floats on the mercury pool. When the coil is powered causing a magnetic field, the plunger assembly is pulled down into the mercury pool which is in turn displaced and moved up to make contact with the electrode, closing the circuit between the top and bottom load terminal, which is connected to the stainless steel can.

To make the unit function as a "Hybrid" time delay, we add a solid state circuit to the coil to delay the power to the coil.

For constant duty applications, a return spring is used in place of the buffer spring. Contact the factory.

The 30 AMP model is designed to save space and simplify mounting methods. The standard mounting bracket on the three pole model allows the unit to be mounted in standard 3" snap track channel. If you do not use snap track mounting, the standard three pole bracket has key hold slots for easy mounting in any panel arrangement. The universal three pole mounting bracket has various mounting holes and key hole slots to meet a variety of mounting centers.

The 30 AMP series is a more compact line with a well proven switch, which is the heart of mercury relays. It is the same switch design that is in our 35 and 60 AMP encapsulated MDRs, which have withstood the test of time and millions of cycles in many different applications.

Typical Specifications:
 

• On Normally Open Units:
• • Operate Time: 50 milliseconds
  • Release Time: 80 milliseconds
• Contact Resistance: 30 AMP = .003 ohm *
• Dielectric Withstant: 2500 VAC RMS
• Longevity: Millions of Cycles
• Temperature Range: -35 degrees C to 85 degrees C
• Coil Terminals: #6 Binding Head Screws
• Load Terminals: #8 Binding Head Screws
• UL Listing: File #E62767
• C.S.A.: File #LR41198

• On Normally Open Units:
• • Operate Time: 50 milliseconds
  • Release Time: 80 milliseconds
• On Normally Closed Units:
• • Operate Time: 30 milliseconds
  • Release Time: 35 milliseconds
• Contact Resistance:
• • 35-AMP = .003 ohm *
  • 60-AMP = .002 ohm*
• Dielectric Withstand: 2500 Vac Rms
• Longevity: Millions of Cycles
• Temperature Range: -35 degrees C to 85 degrees C
• Coil Terminals: #6 Binding Head Screws
• Load Terminals: Pressure Connectors for A.W.G. #4 - #14 on 35-AMP Units and A.W.G. #2 - #8 on 60-AMP Units
• UL Listing: File #E62767 for 35 and 60-AMP N.O. Units 1-4 Poles
• C.S.A.: File #LR41198 for 35 and 60-AMP N.O. Units （Heater Loads） 1-3 Poles
• Auxiliary Devices for Use in Hazardous Locations. UL File #E71867 N.O. Units Approved for Class 1, Groups A, B, C and D, Division 2 Only. To Order for Hazardous Locations, Add the Suffix -X to Part Number.

RATINGS
（Ratings are in amps unless otherwise specified.）

RATINGS
（Ratings are in amps unless otherwise specified.）

For UV Curing, and Various High Voltage applications. Available in Single Pole, Normally Open, and Normally Closed Units. The coils utilize 6-32 Wire Binding Screws, and the Contacts use Compression type terminals for #4 thru #14 AWG wire.
Ratings are: 10 Amps @ 3,500 VAC
15 Amps @ 2,500 VAC
AC Inductive - Power Factor .7 or Greater

1. Inrush Current=1.5 times the steady state current. （No inrush on DC coils）.
2. Minimum operating voltage 90% of nominal voltage.
3. All A.C. voltages are at 50/60 Hz.
4. For other coil voltages, contact factory.
5. Ratings shown are per pole （Coils are in parallel）.

• While MDIs contactors handle high inrush, such as lamp loads, very well, mercury contactors are susceptible to damage by short circuit currents, and should be fused to minimize short circuit fault currents. Fast acting UL class RK-1 and class J fuses and semiconductor I2t fuses more effectively protect relays than other fuses. These are low-peak fuses designed to limit short circuit currents. Regardless, when there is a short circuit, relay operations should be closely monitored afterward because of the possibility of concealed damage that could cause the relays to behave inconsistently.

• Mercury Displacement relays must mount vertically +/- 10 degrees.
• Control line can be protected with metal oxide varistor （MOV）. Use suffix -11.
• Disconnect power before installing or servicing. Observe all electrical and safety codes and ordinances such as National Electrical Code （NEC） and the Occupational Safety and Health Act （OSHA）.