SPR-48 Pulse Isolation Relay

SPR-48 Pulse Isolation Relay

The SPR-48 is a 4-channel pulse isolation relay designed for high-density pulse applications where up to four RPR or SPR relays would be required. Eight isolated solid-state Form A (KY) dry-contact outputs are provided, two each from four Form A inputs. The SPR-48 relay contains standard-duty solid state outputs. The wetting voltage provided by the SPR-48’s input to the sending devices (typically electric meters) is +13 VDC. The SPR-48 may be used with meters having semiconductor outputs or electro-mechanical output relays.

The SPR-48 relay’s Form A inputs feature input filtering circuitry to prevent noise from false triggering the outputs.  Bright red and green LED indicators display the system’s status at all times, thus allowing a rapid check of the system’s performance without requiring any additional test equipment.  The SPR-48’s input and output terminal strips are “Euro” type.  When the stripped wire has been correctly installed in the terminal’s slot, no conductive parts are exposed on the surface of the terminal strip, thus allowing the user maximum protection from accidental electrical shock.  The “K” lead of each of the SPR-48’s outputs is fused to prevent damage to the relays under almost any condition a user might cause such as excessive current, incorrect wiring, etc.

The SPR-48 has built-in MOV transient protection for the solid state relay contacts that eliminates the need for external protection. The SPR-48 is normally mounted inside another enclosure, suitable for the user’s intended application.  An optional NEMA 4X enclosure is available with the SPR-48 mounted on an internal mounting plate.


Power Input:120 or 208-277VAC. Burden: 10 mA at 120 VAC
Pulse Input:Four Form A inputs. “Kin” is common return. Input has “Yin” input terminals are “pulled up” to +13VDC for pulse signal from meter.
Pulse Output:Eight (8) Form A dry contacts (K & Y) for energy pulses. The contacts are solid state rated at 125VAC/VDC at 100milliamps. The maximum power rating of the contacts is 800mW. Each output is factory fused at 1/10 amp. (3AG)
Contact On-State Resistance:25 ohms maximum, 18 typical
Insulation Resistance: 50 megohms typical
Operate and Release Time: 2 to 3 milliseconds typical
Input/Output Isolation Voltage: 2500 Vrms

Mounting: Any position
Size: 7” wide, 9” high, 1.8” deep
Weight: 2 pounds

Temperature Range:

-38º C to +70º C, -38.4º F to +158º F

Humidity: 0 to 98% non-condensing

Available Options
Input Voltages:
  • 125 VDC input using the DCS-1 Power Supply.  
  • +15-48VDC input using the DCS-2 Power Supply
  • +12VDC and +24VDC/24VAC are also available
Contact factory for other input voltages.

All specifications are subject to change without notice.