Spring-Loaded Operating Mechanism

Spring-Loaded Operating Mechanism

DB's Series Decontactors use an internal spring-loaded operating mechanism to open and close the contacts at high speed, independent of the manual motion of the user.

Two Stage Contact System

The operation of the DB's contacts was specifically designed to ensure that load-breaking and load-carrying are performed in separate locations on the contacts.

2 stage contact system for DB

This is accomplished with the motion of the mobile contact relative to the receptacle contact. The opening of the contacts begins with a wiping aciton that moves the contact area toward the edges of the contacts, where load-breaking occurs. This allows numerous overload-breaking operations without deteriorating the main contact surfaces or the continuity of the connection.

Arc-Extinguishing System

For higher currents, or when significant overloads are involved, additional provision is desirable to handle the arcing that occurs during load-breaking. MELTRIC accomplishes this on its DB Series Decontactors with a series of magnetic V-shaped blades, which create an arc chute.

arc extinguishing system for DB

As the contacts open, the mobile intermediate contact moves along the arc chute. The arc is transferred to the magnetic "V" shaped blades, which splits and destablilizes it. This helps to cool and quickly extinguish the arc, minimizing any potential damage to the contacts. Together with the spring operator, two stage contact system and silver-nickel butt style contacts, this feature allows the DB series to easily and safely break high horsepower inductive loads and significant overloads.

Limitations of Pin & Sleeve Style Contacts (used by competitors)

Pin and Sleeve Contacts

resistance chart

  • Manufacturing variations can cause too tight or too loose of a fit between the pin and the sleeve.

  • Wear from normal use reduces contact force, increasing resistance and heat build-up, possibly leading to overheating and catastrophic equipment failure.

  • The design requires the use of cheap and easy to machine materials such as brass, which has inferior electrical properties.