Machinery protection planning

Build a spare strategy around the actual 3500 rack configuration.

This case helps document a Bently Nevada 3500 rack before an outage, with emphasis on power-supply redundancy, TDI dependency, monitor modules and field wiring.

Use the installed rack bill of materials and current Baker Hughes documentation. Do not infer compatibility from module appearance alone.

Architecture facts to verify

Rack layout

The standard 3500 full-size rack reserves the left-most positions for two power supplies and the rack interface/TDI position. The remaining positions accept monitor and related modules.

Power strategy

A 3500 rack can use one or two 3500/15 power supplies. With two supplies, either supply is capable of powering a full rack, supporting redundancy planning.

TDI dependency

The 3500/22M Transient Data Interface supports rack configuration and communication with System 1. Treat its configuration and rear I/O details as part of the recovery record.

Phase reference

The 3500/25 Enhanced Keyphasor module provides phase-reference information used for speed and vector measurements. Record probe type and channel use.

Rack survey planner

Power supplies installedVerified spare power supplyVerified TDI configuration backupCritical monitor modules have tested sparesRear I/O and field wiring documented

Planning risk: 8 — HIGH

What belongs in the rack record

Item	Record	Reason
3500/05 rack	Rack size, mounting format, slot map	Defines physical architecture.
3500/15 supply	AC/DC type, quantity, input range, spare status	Power redundancy must be understood before service.
3500/22M TDI	Part number, rear I/O, configuration backup	Supports rack configuration and System 1 communication.
Monitor modules	Exact model, channel use, I/O module, spare status	Installed function differs by monitor type.
3500/25 Keyphasor	Channel inputs, probe/pickup source	Phase reference can affect diagnostics.
Relay modules	Output mapping and voting logic	Trip logic must be documented before replacement.

Spare tiers

Tier A · Immediate recovery

Modules whose failure can remove rack power, protection coverage or a critical interface with no practical workaround.

Tier B · Short-window recovery

Modules with partial redundancy or temporary operational alternatives, but still significant outage exposure.

Tier C · Planned replacement

Non-critical or duplicated functions where procurement can follow a planned maintenance window.

Official references

Baker Hughes — 3500 Machinery Protection System resources
Baker Hughes — 3500 System Datasheet

Reusable worksheet

Download 3500 rack survey CSV

Maintainer

Maintained by PLCProTech Ltd. as an open industrial automation engineering reference.