The Bently Nevada 125720-01 is the 4-Channel Relay I/O Module for the 3500/32 and 3500/32M Relay Modules in the 3500 Machinery Protection System. It is a rear-rack I/O card that provides the physical relay contacts and terminal connections for the four programmable relay outputs, executing the trip, alarm, and shutdown logic generated by the front-panel relay control module.
Item No :
125720-01Order(MOQ) :
1 PiecePayment :
EXW/CIFProduct Origin :
USAShipping Port :
WuhanLead Time :
3-5daysWeight :
3kg| Specification | Description |
|---|---|
| Manufacturer | Bently Nevada (Baker Hughes) |
| Model | 125720-01 |
| Product Family | 3500/32 / 3500/32M 4-Channel Relay Module |
| Product Type | Relay I/O Module (Rear-Rack) |
| Function | Provides physical relay contacts for the 4-channel relay control module |
| Relay Type | Single-Pole Double-Throw (SPDT / Form C) |
| Contact Material | Epoxy-sealed, with 250 Vrms arc suppressor |
| Contact Life | 100,000 cycles @ 5 A, 24 Vdc or 240 Vac |
| Max Switched Current | 2 A (standard systems) |
| Max Switched Voltage | 125 Vdc / 250 Vac |
| Max Switched Power | 450 VA (standard systems) |
| Isolation | 1500 VAC (coil to contact) |
| Operating Mode | Each relay switch-selectable for Normally Energized or Normally De-energized |
| Rack Position | Rear slot directly behind the 3500/32 main module |
| Rack Space | 1 full-height rear slot |
| Dimensions (H x W x D) | 241 mm x 24.4 mm x 99.1 mm |
| Weight | Approx. 0.4–0.5 kg |
| Operating Temperature | -30°C to +65°C (-22°F to +150°F) |
| Storage Temperature | -40°C to +85°C (-40°F to +185°F) |
| Humidity | 95%, non-condensing |
| Country of Origin | USA |
| Lifecycle Status | Active / Available as New Surplus; available for repair only per official spares list |
| Model | Description | Typical Application |
|---|---|---|
| 125720-01 (this model) | Spare 4-Channel Relay I/O Module (standard) | Repair/replacement for standard 3500/32 applications |
| 125720-02 | Spare 4-Channel Relay I/O Module (hazardous area/functional safety) | SIL-certified and hazardous area applications |
| 125712-01 | 4-Channel Relay Module (main card) | Front-panel control module for standard 3500/32 |
| 149986-02 | Spare 4-Channel Relay Control Module | Replacement main card for 3500/32M |
| 3500/32-01-00 | Complete 4-Channel Relay Module assembly | Standard alarm/shutdown logic |
| 3500/32M | Enhanced 4-Channel Relay Module (SIL 2 capable) | Functional safety applications |
Q1: What is the primary function of the 125720-01?
It is the rear I/O module for the 3500/32 and 3500/32M 4-Channel Relay Modules. It provides the physical SPDT relay contacts and terminal connections that execute the trip, alarm, and shutdown logic programmed in the front-panel relay control module. It interfaces directly with the main relay card from the rear of the rack to switch external devices such as ESD systems, annunciators, and PLCs .
Q2: Can the 125720-01 be used as a standalone relay module?
No. The 125720-01 is a rear-facing I/O module that must be installed directly behind a corresponding 3500/32 or 3500/32M Relay main module to function. It cannot operate independently without the front-panel control card .
Q3: What is the difference between 125720-01 and 125720-02?
The 125720-01 is the standard relay I/O module for general-purpose applications. The 125720-02 is designed for hazardous area systems and functional safety systems (SIL 2 capable), with different contact ratings and certification for Division 2/Zone 2 environments .
Q4: What are the contact ratings for the 125720-01?
For standard systems, the relay contacts are rated for 2 A @ 0–30 Vdc, 0.75 A @ 48 Vdc, or 0.2 A @ 125 Vdc. For AC resistive loads, the maximum switched voltage is 250 Vac with a maximum switched power of 450 VA . Contact life is rated at 100,000 cycles at full rating .
Q5: What spare parts are available for the 3500/32 relay system?
Key spares include:
125720-01: Spare 4-Channel Relay I/O Module (available for repair only)
125720-02: Spare 4-Channel Relay I/O Module for hazardous area/functional safety systems
149986-02: Spare 4-Channel Relay Control Module (main card)
129771-01: User Guide for 3500/32 and 3500/32M Relay Modules
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