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Critical Machines - Machine Monitoring and Protection API-670 with Journal Bearings
Last Updated: 05/22/2017
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Critical Machines

Machinery Applications Include: Electric Motors, Steam Turbines, Expanders, Compressors, Blowers, Fans, Pumps, Positive Displacement Compressors, Gears, Speed Changers, Journal Bearings, Radial Vibration, Thrust, Vibration Monitoring, Protection System, VMS, API 670.

Large Critical Machines exist in all industries including HPI, Chemical, Pipeline, Power Generation, Pulp and Paper and Water Treatment. Critical Machines are defined by the following criteria; criticality to production, capital cost, replacement cost and safety. As they may be only partially spared or not spared at all production will be lost if they fail. As Critical Machines tend to be high horsepower and heavily loaded Journal or Smooth Bore Bearings are most often used.

As most Critical Machines have already been supplied with Protection Systems many of which are or becoming obsolete a replacement systems can be modeled after the existing systems hardware. The following will help you insure that the system being provided for new or replacement vibration monitoring systems meets the intent of API-670.

Critical Machines or Critical Machine Trains are made up of many combinations of Drivers, Speed Changers and Driven Equipment. An all-inclusive Vibration Monitoring System can be ascertained by looking at the requirements for each machine component (case) individually and summing them together for a complete system.

Drivers:
Drivers can be an Electric Motor, Steam Turbine or an Expander. Aircraft Derivative Gas Turbines will be covered in a separate application note. Industrial Gas Turbines have Journal Bearings. Electric Motors do not have Thrust Bearings and depend on a simple rider ring for shutdown. Electric Motors quickly find their electrical centers (Thrust Position) on power up.

Drivers

Driven Equipment:
Driven Equipment varies and includes Compressors, Blowers, Fans and Pumps. Positive Displacement Compressors and Pumps will be covered in a separate article.

Driven Equipment

Gears (Speed Changers):
Speed Changers or Gears are of two varieties, speed increasers and speed decreasers. Vibration Monitoring is the same for either. Double Herringbone type gears may negate the requirement for Thrust Position Sensors on both the input and output shaft.

Gears

Vibration Monitoring System Budgetary BOM:

#

Qty.

Part#

Description

Comment

A. Sensors

1

Radial Vibration Sensors*

Proximity Probe Systems

1 per Radial Vibration (X&Y)

2

Thrust Position Sensors*

Proximity Probe Systems

1 per Thrust Position (TP)

3

Keyphasor Sensors*

Proximity Probe Systems

1 per Driver and 1 per Gearbox

4

CMCP786

Industrial Accelerometer

1 per Gearbox

5

CMCP602L-16

Accelerometer Extension Cable

1 per Gearbox

B. Mounting Hardware

6

CMCP4190**

Proximity Probe NPT Adapters

1 per External Mounted Probe

7

CMCP803**

Conduit Head

1 per CMCP4190

and/or

8

CMCP801**

Proximity Probe Holder

1 per Internal Mounted Probe

and/or

9

CMCP805**

Probe Mounting Block

1 per External Mounted Probe

and

10

CMCP140-08

Proximity Probe Driver Enclosure

1 per Machine Case, 2 per Gearbox

C. Monitoring System

11

CMCP7500MMS-XX

19 EIA Rack Mount System

XX = Number of Channels (X+Y+TP+K0)

CMCP540

Radial Vibration Transmitters

Per X and Y

CMCP545

Thrust Position Transmitter

Per TP

CMCP595

Accessory Module

Per K0

*Part Number Determined by Installation Requirements.
**Method of Mounting Determined by Installation Requirements.



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