PRINCIPLE OF OPERATION
The 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.
APPLICATION DATA
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.
DESIGN FEATURES
Mercury Displacement Relays provide a perpetually self-
renewing contact to assure maximum contact life and
minimum contact resistance. Conventional contactors
are destroyed by pitting and welding under high load
conditions. MDRs have a single moving part that floats
free on a pool of mercury. There are no hinges, pivots,
pins or mechanical linkage to wear out or break. The result
is a life expectancy which exceeds other types of contactors
handling the same loads and duty cycle.
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 withstanding voltage between
contact surfaces.
Low Contact Resistance - Large electrode and mercury
volume creates low contact resistance and provides high
inrush current capability.
Quiet Operation - Audible noise normally associated with
conventional 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.
RECOMMENDED FUSE PROTECTION
MDRs are capable of accepting high inrush currents
however, short circuit currents can damage the contactor.
Fast acting fuses should be used in-line with the contactor
load to protect against short circuit fault current. UL class
J and class RK-1 fuses are recommended.
GLASS INSULATOR
WELD
PLUNGER GUIDE
CERAMIC LINER
ELECTRODE
ARC QUENCHING ATMOSPHERE
MAGNETIC LINER
PLUNGER GUIDE
BUFFER SPRING
MERCURY POOL
STAINLESS STEEL CAN
MERCURY DISPLACEMENT TUBE
MDR
MERCURY DISPLACEMENT RELAYS
APPLICA
APPLICATION D
TION DA
AT
TA
A
3...11
9/04
PHONE: (843) 393-5778 FAX: (843) 393-4123 EMAIL: info@magnecraft.com
MDR MERCURY DISPLACEMENT RELAYS
LISTED 367G
File E52197
CONTACT LOAD RATINGS TABLE
RESISTIVE
AMPS
(AC1) (DC1)
TUNGSTEN
AMPS
VOLTAGE
M35
ML35
M60
ML60
M100
1Ø 3Ø
1/2
1/2
1/2
1/2
30
19
14
11
27
13.5
5.2
2.6
34
28
14
11.2
5*
7.5*
10*
10*
3*
5*
5*
5*
MOTOR
AMPS
HP
1Ø 3Ø
3/4
3/4
3/4
3/4
3*
5*
7.5*
7.5*
5*
10*
15*
15*
39
19.5
7. 4
3.7
28
21
16
30
28
21
17
34
HERMETICALLY SEALED
STAINLESS STEEL TUBES
Every contactor tube is hermetically sealed for maximum life.
The MDR provides protection to the user from arcing and
other hazards of switching heavy loads with exposed contacts.
120 VAC
240 VAC
480 VAC
600 VAC
24 VDC
48 VDC
125 VDC
250 VDC
120 VAC
240 VAC
480 VAC
600 VAC
120 VAC
240 VAC
480 VAC
600 VAC
24 VDC
48 VDC
125 VDC
250 VDC
120 VAC
240 VAC
480 VAC
600 VAC
120 VAC
240 VAC
480 VAC
600 VAC
24 VDC
48 VDC
125 VDC
250 VDC
35*
35*
35*
35*
35*
35*
16*
12*
35*
35*
35*
35*
60*
60*
60*
50
60*
60*
40*
20*
60*
60*
60*
50
100*
100*
100*
80
100*
100*
80*
40*
35* 35*
17 17
9 9
7 7
35* 35*
35* 35*
16* 16*
12* 12*
35* 35*
17 17
9 9
7 7
60* 45*
30 22.5
15 11.2
12 9
50* 50*
50* 50*
40* 40*
20* 20*
60* 45*
30 22.5
15 11.2
12 9
100*
60*
30*
24
100*
100*
80*
40*
NO NC
FEATURES
SILENT OPERATION
HIGH DC VOLTAGE RATINGS
OPTIONAL DIN MOUNT ADAPTERS
STABLE CONTACT RESISTANCE
* UL and CSA Listed
80
80
78
65
110
10
7 to 26.4
3.1 to 9.1
Class B (130 ºC)
Continuous
Mercury
1 @ 5 VDC or 5 W
50
80 to 100
2650
2650
2650
2650
1000 @ 500
-40
+60
-40
+60
-55
+100
100,000
5,000,000
Vertical ±10%
M35: AWG 6-14 wire
pressure connectors
M60: AWG 2-12 wire
pressure connectors
M100: AWG 1-8 wire
pressure connectors
#6-32 pan
head screws
370 to 1078
COIL
COIL
Pull-in Voltage AC (50/60 Hz):<
Pull-in Voltage DC:<
Dropout Voltage AC (50/60 Hz):>
Dropout Voltage DC:>
Maximum Voltage:
Resistance Tolerance:
Coil Power AC (50/60 Hz):
Coil Power DC:
Insulation System
Per UL Standard 1446:
Duty:
CONT
CONTA
ACTS
CTS
Material:
Minimum Recommended Load:
TIMING
Operate Time @ Nominal voltage:
Release Time @ Nominal voltage:
DIELECTRIC S
DIELECTRIC STRENGTH
TRENGTH
Coil to Contacts:
Across Open Contacts:
Pole to Pole:
Contacts to Frame:
Insulation Resistance:
TEMPER
TEMPERA
ATURE
TURE
Operating, AC Lower:
Operating, AC Upper:
Operating, DC Lower:
Operating, DC Upper:
Storage, Lower:
Storage, Upper:
LIFE EXPECT
LIFE EXPECTANC
ANCY
Y
Electrical @ Rated Load (AC1):
Mechanical @ no Load :
MISCELLANEOUS
Operating Position:
Load Terminals:
Coil Terminals:
Weight:
UNITS
UNITS
% of nominal
% of nominal
% of nominal
% of nominal
% of nominal
% ±
VA
W
amps
ms
ms
V rms
V rms
V rms
V rms
megohms
minimum@VDC
ºC
ºC
ºC
ºC
ºC
ºC
operations
operations
grams
GENER
GENERAL SPECIFIC
AL SPECIFICA
ATIONS (@
TIONS (@ 25
25ºC
ºC)
)
3...12
9/04
STANDARD
PART
NUMBERS
NOMINAL
INPUT
VOLTAGE
NOMINAL
RESISTANCE
(OHMS)
MDR MERCURY DISPLACEMENT RELAYS
1, 2 & 3 POLES
35, 60 AMPS
1 POLE 100
AMPS
2 POLES
35 OR 60 AMPS
3 POLES
35 OR 60 AMPS
1 POLE
35 OR 60 AMPS 700 W
2,800 W
186 W
218 W
1,200 W
98 W
111 W
430 W
63 W
460 W
700 W
2,800 W
218 W
1,200 W
111 W
430 W
700 W
2,800 W
186 W
218 W
1,200 W
98 W
111 W
430 W
63 W
460 W
700 W
2,800 W
218 W
1,200 W
111 W
430 W
73.5 W
300 W
53 W
WM35A-120A
WM35A-240A
WM35A-24D
WM35AA-120A
WM35AA-240A
WM35AA-24D
WM35AAA-120A
WM35AAA-240A
WM35AAA-24D
WM35B-120A
WML35A-120A
WML35A-240A
WML35AA-120A
WML35AA-240A
WML35AAA-120A
WML35AAA-240A
WM60A-120A
WM60A-240A
WM60A-24D
WM60AA-120A
WM60AA-240A
WM60AA-24D
WM60AAA-120A
WM60AAA-240A
WM60AAA-24D
WM60B-120A
WML60A-120A
WML60A-240A
WML60AA-120A
WML60AA-240A
WML60AAA-120A
WML60AAA-240A
WM100A-120A
WM100A-240A
WM100A-24D
120 VAC 50/60Hz
220/240 VAC 50/60Hz
24 VDC
120 VAC 50/60Hz
220/240 VAC 50/60Hz
24 VDC
120 VAC 50/60Hz
220/240 VAC 50/60Hz
24 VDC
120 VAC 50/60Hz
120 VAC 50/60Hz
220/240 VAC 50/60Hz
120 VAC 50/60Hz
220/240 VAC 50/60Hz
120 VAC 50/60Hz
220/240 VAC 50/60Hz
120 VAC 50/60Hz
220/240 VAC 50/60Hz
24 VDC
120 VAC 50/60Hz
220/240 VAC 50/60Hz
24 VDC
120 VAC 50/60Hz
220/240 VAC 50/60Hz
24 VDC
120 VAC 50/60Hz
120 VAC 50/60Hz
220/240 VAC 50/60Hz
120 VAC 50/60Hz
220/240 VAC 50/60Hz
120 VAC 50/60Hz
220/240 VAC 50/60Hz
120 VAC 50/60Hz
220/240 VAC 50/60Hz
24 VDC
1 POLE NORMALLY OPEN, 35 AMP
2 POLE NORMALLY OPEN, 35 AMP
3 POLE NORMALLY OPEN, 35 AMP
1 POLE NORMALLY CLOSED, 35 AMP
ML SERIES 2 POLE NORMALLY OPEN, 35 AMP
ML SERIES 3 POLE NORMALLY OPEN, 35 AMP
ML SERIES 1 POLE NORMALLY OPEN, 35 AMP
1 POLE NORMALLY OPEN, 60 AMP
2 POLE NORMALLY OPEN, 60 AMP
3 POLE NORMALLY OPEN, 60 AMP
1 POLE NORMALLY CLOSED, 60 AMP
ML SERIES 1 POLE NORMALLY OPEN, 60 AMP
ML SERIES 2 POLE NORMALLY OPEN, 60 AMP
ML SERIES 3 POLE NORMALLY OPEN, 60 AMP
1 POLE NORMALLY OPEN, 100 AMP
CLASS WM35, WM60 & WM100 SWITCH RESISTIVE, TUNGSTEN,
AND MOTOR LOADS. HIGH INRUSH CAPACITY. RECOMMENDED
FOR DC LOADS. CLASS WML35 & WML60 RECOMMENDED FOR
LONGER LIFE WHEN SWITCHING AC RESISTIVE AND TUNGSTEN LOADS.
1 POLE
100 AMPS
OTHER COIL VOLTAGES ARE AVAILABLE ON SPECIAL ORDER.
CONTACT FACTORY FOR DETAILS
PHONE: (843) 393-5778 FAX: (843) 393-4123 EMAIL: info@magnecraft.com
COIL MEASURED @ 25 ºC
3...14
9/04