BENTLY 3500/25 125792-01

Description

Description
The 3500/25 Enhanced Keyphasor Module is a half-height, two-channel module
used to provide Keyphasor signals to the monitor modules in a 3500 rack. The
module receives input signals from proximity probes or magnetic pickups and
converts the signals to digital Keyphasor signals that indicate when the
Keyphasor mark on the shaft coincides with the Keyphasor transducer. The 3500
Machinery Protection System can accept up to four Keyphasor signals for
normal configuration and up to eight Keyphasor signals in a paired
configuration.
Note: A Keyphasor signal is a once-per-turn or multiple-event-per-turn pulse from a rotating shaft or gear used to
provide a precise timing measurement. This allows 3500 monitor modules and external diagnostic
equipment to measure shaft rotative speed and vector parameters such as 1X vibration amplitude and
phase.
The Enhanced Keyphasor Module is an improved 3500 system module. It offers
expanded Keyphasor signal processing capabilities over the previous design
while maintaining complete downward-compatibility in terms of form, fit and
function with existing Keyphasor modules for use in legacy systems. The
Keyphasor module, PWA 125792-01, is completely replaced by the more recent
149369-01 module.
When a system Keyphasor input is required for Triple Modular Redundant (TMR)
applications, the 3500 system should employ two Keyphasor modules. In this
configuration the modules work in parallel to provide both a primary and
secondary Keyphasor signal to the other modules in the rack.
A system with more than four Keyphasor inputs may use a paired configuration
provided that there are no more than four primary Keyphasor input signals. A
paired configuration requires two consecutive monitoring positions in either the
upper/lower or both half-slot positions. Four Keyphasor modules will accept four
primary and four backup input channels and provide four output channels (one
per module). A configuration of two paired and one non-paired (three Keyphasor
modules total) is also possible. In such a configuration, the user may configure
the one non-paired Keyphasor (order either two 2-channel or one 1-channel and
one 2-channel option)
The Isolated Keyphasor I/O module is designed for applications in which the
Keyphasor signals are tied in parallel to multiple devices and require isolation
from other systems, such as a control system. The Isolated I/O module was
created specifically for Magnetic Pickup applications but is compatible with and
will provide isolation for Proximitor* applications as long as an external power
supply is provided. Note that the intent of this I/O module was primarily to
measure shaft speed and not phase. The module can provide phase
measurements, but this I/O introduces a slightly higher phase shift than the NonIsolated I/O version. Figure 1 shows the amount of phase shift that the Isolated
I/O modules will add at different machine speeds.
Enhanced product features include generation of once-per-turn event signals
from multi-event-per-turn inputs, field-upgradeable firmware, and asset
management data reporting.

Specifications
Inputs
Power
Consumption
3.2 Watts typical.
Signal
Each Keyphasor Module accepts
up to two transducer signals from
proximity probe transducers or
magnetic pickups. The input
signal range is +0.8 V to -21.0 V
(Non-Isolated I/O modules) or +5V
to -11V (Isolated I/O modules).
Signals exceeding this range are
limited internally by the module.
Passive magnetic pickups require
a shaft rotative speed greater
than 200 rpm (3.3 Hz).
Input
Impedance
21.8 k  minimum.
Signal Conditioning
Speed/
Frequency
Signal Ranges
Input range of 1 to 1,200,000 cpm
(0.017 to 20 kHz). Supports
multiple events per revolution to a
maximum of 20 kHz.
Output range of 1 to 99,999 cpm
(0.017 to 1667 Hz)
Speed/
Frequency
Signal Accuracy
Specified at +25 C (+77 F).
Non-processed
Signals
 0.017 to 100 Hz … 1 cpm
 101 to 500 Hz … 8 cpm
 501 to 20 kHz … 1% of cpm