GF Signet 2551 Magmeter Flow Sensor - Display - Manual (Page 7)

7 2551 Magmeter
Relay 3 is a solid state relay. It can be applied exactly the same as a dry
contact relay, but the current rating is 0.2 A (200 mA) maximum. Relay 3 is
best suited to pulse applications and low voltage loads.
Relays 1 and 2 are dry contact relays rated for 5 A maximum current.
They are best suited for switching high voltage loads, such as AC powered
pumps and valves.
When used to switch inductive loads, dry contact relays may be damaged by
arcing. Signet recommends the installation of a ¿ lter device to prevent such
damage.
3-8050.396 159 000 617 RC Filter kit (for relay use)
Relay 3 Type: Solid State
Rating: 50 mA @ 30 VDC, 50 mA @ 42 VAC
Relay 1, Relay 2 Type: Mechanical SPDT
Rating: 5A @ 30 VDC max., 5 A @ 250 VAC max
5.5 Wiring Relays
Solid State Relay 3:
50 mA max @ 30 VDC
50 mA max @ 42 VAC
NO1
NO2
NO3
NC1
NC2
NC3
C1
C2
C3
V+
V-
Auxiliary Power
9 to 24 VDC
0.4 A Maximum
Mechanical Relays:
5A @ 250 VAC
5A @ 30 VDC
Relay 1
Relay 2
Relay 3
Aux Pwr
Auxiliary power must be connected to operate the relays and to
power the display backlighting. Auxiliary power is fully isolated.
The Loop Power supply may be used for Aux power if the power
source provides a suf¿ cient current rating.
Relay Terminal Legend:
NO: Normally Open
NC: Normally Closed
C: Common
Application Notes: Relay Wiring
• Inductive relay loads may generate transient voltage spikes well in excess of the relay contact ratings. This will cause arcing across
the contacts and consequently rapid relay wear. Signet recommends an RC-style ¿ lter (“snubber”), installed as illustrated here.
• The ¿ lter kit (3-8050.396) is available as an accessory item. See ordering information on back cover.
• Signet product warranty does not cover damage to relays due to contact burnout.
3-8050.396
NO1
NO2
NO3
NC1
NC2
NC3
C1
C2
C3
V+
V-
120-240 VAC
AC-powered:
Pumps
Alarm lamps
Audio alarms
Mixers
Defi nition:
An inductive load is an electrical device generally made
of wire that is coiled to create a magnetic ¿ eld to produce
mechanical work when energized.
Examples of inductive loads include motors, solenoids,
and relays.
High voltage transients from these types of loads can
cause arcing across mechanical switching contacts or
can cause damage to solid-state contacts.