APPLICATION DATA
MDR
C L A S S
PAGE 159
WEBSITE: www.magnecraft.com EMAIL:info@magnecraft.com FAX ON DEMAND 1-800/891-2957, DOCUMENT 100
MERCURY POOL
STAINLESS STEEL CAN
PLUNGER GUIDE
MAGNETIC LINER
GLASS INSULATOR
WELD
MERCURY DISPLACEMENT TUBE
T
he sectional view shows our normally open style Mercury Displacement tube with the plunger assembly
floating on the mercury pool.
When the coil power is off, the mercury level is below the electrode tip. No electrical path exists between
the electrode and mercury pool.
When coil power is applied, the plunger is drawn down into the mercury by the pull of the magnetic field.
This action raises the mercury level, so it covers the end of the electrode closing the circuit.
When coil power is turned off, the buoyant force of the mercury causes the plunger assemble to rise,
dropping the mercury level, and breaking the circuit.
Mercury Displacement relays are ideal for adverse environments-
....Where high inrushes are encountered
....Where hermetically sealed contact operation is required because of corrosive, dirty, or moist ambient
conditions.
....Where use does not permit contact maintenance.
....Where reduced noise levels are required.
....where minimum weight and size are desired.
Liquid Mercury Contact
- provides a new contact surface with every actuation. Mercury is self-renewing
and does not pit, weld, disintegrate or oxidize.
Hermetic sealing
- provides internal and external protection from arcing.
Inert Gas atmosphere
- contactor tube is evacuated, then pressurized with a combination of gases which
extinguish arcing and contribute to long life. The pressurized gases provide for a high dielectric withstand-
ing voltage between contact surfaces.
Low Contact Resistance
- Large electrode and mercury volume creates low contact resistance and
provides high inrush current capability.
Quiet Operation
- Switch clacking normally associated with conventional hard contactors, is eliminated
with mercury displacement tubes and the buffer spring assembly.
APPLICATION OF "M" SERIES VS "ML" SERIES
The series "ML" is physically the same as the "M" series except for the type of gases used in the
contactor tubes. The "ML" series was developed for use with resistive and tungsten loads on AC power
ONLY. The "ML" series will give much greater life than the "M" series for these types of loads and is
intended for high activation use, such as molding machines or ovens.
The "ML" series, however is not intended for use with motor loads on AC power, or for resistive, tungsten,
or motor loads on DC power. The "M" series, which is our universal series is rated
to be used on all types of loads resistive, tungsten, and motor for both AC and DC power
PRINCIPLE OF OPERATION
APPLICATION DATA
DESIGN FEATURES
BUFFER SPRING
ARC QUENCHING ATMOSPHERE
ELECTRODE
CERAMIC LINER
PLUNGER GUIDE