Field coil power requirements – Watlow HG Series Mercury Displacement Relay User Manual
Page 4
Temperature Control Output to MDR Coil Input
Please refer to the Field Coil Power Requirements when selecting the correct temperature control output.
Example: An HG35-1LD3-X000 requires 224mA to energize the coil and could be used with Watlow
temperature control output options ‘B’ or ‘K’ (i.e. 988A-XXBB-XXXX or 988A-XXKK-XXXX) models. The
best selection is the ‘B’ output option because it includes an RC snubber across the output. If you select
the ‘K’ option, it is recommended that you also purchase a Quencharc® snubber separately (Watlow part
number 0804-0147-0000). Place the snubber across the MDR coil terminals to protect the temperature
control solid state output. When placing the snubber across the coil of a 2 and 3 pole relay, you may have
to add some lead wire to the snubber. The MDR coil is an inductive load and the snubber will reduce the
flyback voltage produced by the MDR coil when it de-energizes. See below.
Note: Watlow temperature control solid state outputs will not drive VDC coils directly. Refer to the coil
current specifications above and any temperature control output specifications as required by the
application.
Quencharc
Snubber
(Purchase
Separately)
HG30-XAAX-0000
1 Pole
2 Pole
3 Pole
Voltage
Current
Power
Current
Power
Current
Power
24V~ (ac)
NA
NA
0.456A
10.9VA
0.510A
12.2VA
120V~ (ac)
NA
NA
0.121A
14.5VA
0.106A
12.7VA
208V~ (ac)
NA
NA
0.055A
11.4VA
0.055A
11.4VA
240V~ (ac)
NA
NA
0.063A
15.1VA
0.062A
14.9VA
24V
Î
(dc)
NA
NA
0.240A
5.8W
0.250A
6.0W
HG30-XKDX-0000
HG35-XLDX-0000
HG50-XMDX-0000
HG60-XPDX-0000
1 Pole
2 Pole
3 Pole
Voltage
Current
Power
Current
Power
Current
Power
24V~ (ac)
0.235A
5.6VA
0.529A
12.7VA
1.270A
30.5VA
120V~ (ac)
0.057A
6.8VA
0.133A
16.0VA
0.224A
26.9VA
208V~ (ac)
0.030A
6.2VA
0.075A
15.6VA
0.111A
23.1VA
240V~ (ac)
0.035A
8.4VA
0.087A
20.9VA
0.128A
30.7VA
24V
Î
(dc)
0.146A
3.5W
0.266A
6.4W
0.470A
11.3W
HG80-XABX-0000
HG1M-XACX-0000
HG2M-XADX-0000
1 Pole
2 Pole
3 Pole
Voltage
Current
Power
Current
Power
Current
Power
24V~ (ac)
0.930A
22.3VA
2.310A
55.4VA
5.060A
121.4VA
120V~ (ac)
0.195A
23.4VA
0.448A
53.8VA
0.968A
116.2VA
208V~ (ac)
0.097A
20.2VA
0.280A
58.2VA
0.482A
100.3VA
240V~ (ac)
0.112A
26.9VA
0.323A
77.5VA
0.563A
135.1VA
24V
Î
(dc)
0.219A
5.2W
0.572A
13.7W
0.555A
13.3W
Field Coil Power Requirements
Watlow Series HG Mercury Displacement Relay User’s Manual 4