Bently Nevada 3500/33 16-Channel Relay Module

Bently Nevada 3500/33 16-Channel Relay Module

Configured for relay output execution in the Bently Nevada 3500 Machinery Protection System, the Bently Nevada 3500/33 (149986-01 + 149992-01) provides direct electrical switching through 16 independent SPDT relay channels. The 3500/33 uses the 149986-01 front module with the 149992-01 rear I/O module to execute programmed alarm, trip, and voting logic.

Hardware Specifications

Machinery Protection Relay Logic and Electrical Switching

The 3500/33 operates at the relay interface between the 3500 monitoring system and external alarm or shutdown circuits. The 149986-01 control module manages relay logic, while the 149992-01 rear module provides the corresponding field wiring interface.

Each of the 16 channels uses an SPDT relay. The channels operate in four groups of four, and each group can use Normally De-energized (ND) or Normally Energized (NE) operation through hardware selection.

The relay contacts switch external circuits according to configured alarm and voting logic. Therefore, field wiring must remain within the specified voltage, current, and switching-power limits.

The module also provides OK, TX/RX, and channel alarm indicators for local status and diagnostic observation. The TX/RX indicator corresponds to rack communication activity rather than a field relay contact signal.

For mechanical monitoring applications, the relay outputs can interface with protection circuits associated with rotor vibration, shaft position, speed, or other monitored machine conditions. However, the supplied specifications do not define the individual alarm logic assigned to each channel.

Frequently Asked Questions

Q: Does the 3500/33 provide 16 relay channels through one front module?
A: The complete assembly uses the 149986-01 front relay control module together with the 149992-01 rear relay output module. Together, they provide 16 relay channels.

Q: What relay contact limits apply to the 3500/33?
A: The specified limits are 125 VDC or 250 VAC maximum switched voltage, 5 A maximum switched current, 70 W at 24 VDC, and 1200 VA at 250 VAC. The minimum switched current is 100 mA at 5 VDC.

Q: Which software versions support this relay module?
A: The supplied data specifies 3500 Rack Configuration Software version 3.3 or later and 3500 Data Acquisition Software version 2.40 or later.

Field Installation Guidelines

• Install the 149986-01 front module in the designated full-height front slot of the 3500 rack.
• Install the 149992-01 rear I/O module in the corresponding full-height rear position.
• Verify that the relay contact load remains within the specified voltage, current, and power limits.
• Configure each relay group according to the required Normally De-energized (ND) or Normally Energized (NE) operating mode.
• Route relay wiring separately from low-level vibration and measurement signal wiring where practical.
• Maintain appropriate physical separation between relay circuits and sensitive monitoring signals to reduce electrical coupling.
• Connect field wiring according to the applicable 3500 rack wiring documentation and site electrical standards.
• Verify relay contact state and channel indication during commissioning before connecting the outputs to final alarm or shutdown circuits.
• Confirm rack communication through the TX/RX indication and check the OK status before placing the protection circuit into service.
• Use the specified software versions or later versions identified in the supplied technical data.