1794-OW8

Overview

Allen-Bradley 1794-OW8 is a FLEX I/O relay output module featuring eight Form A isolated electromechanical relays. It provides reliable switching for AC and DC loads in distributed control systems.

Output Specifications

• Outputs per module: 1 group of 8 Form A (normally open) isolated relays

• Relay contact ratings:

  • 250 V AC, 2 A, 50/60 Hz (resistive)

  • 120/240 V AC, 50/60 Hz: 1800 VA make, 180 VA break

  • 5–30 V DC, 2 A (resistive)

• Pilot duty rating: R150, 5–30 V DC, 28 VA (≤1 A below 28 V DC)

• Minimum contact load: 100 µA @ 100 mV DC

• Off-state leakage current (max @ 240 V AC): 1.0 mA (through snubber circuit)

• Initial contact resistance: 30 mΩ

• Switching frequency (max): 1 operation/3 s (0.3 Hz at rated load)

• Bounce time (mean): 1.2 ms

• Expected life of contacts: ≥100,000 operations @ rated loads

Module Location

• Mounts on:

  • 1794-TB2

  • 1794-TB3

  • 1794-TB3S

  • 1794-TBN

  • 1794-TBNF

• Fuse requirement (TBNF base): 3.0 A, 250 V AC slow-blow fuse (Littelfuse 239003)

Power Specifications

• Flexbus current: 5 V DC, 35 mA

• Supply voltage: 24 V DC, 125 mA

• Power dissipation (max): 5.5 W

• Thermal dissipation (max): 18.8 BTU/hr

Timing Characteristics

• Output signal delay (max):

  • OFF → ON: 10 ms (relay energization)

  • ON → OFF: 10 ms (relay de-energization)

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