Bently Nevada 3500/25 Data sheet

3500/25 Enhanced Keyphasor Module

Datasheet

Bently Nevada Machinery Condition Monitoring

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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.

Keyphasor signal is a once-per-turn or multiple­event-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.

141532 Rev. T

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 updated 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 there are no more than four

3500/25 Enhanced Keyphasor Module
Datasheet 141532 Rev. T

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 2­channel option)

The Isolated Keyphasor I/O module is designed
for applications where 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.

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 Non-Isolated 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 multi­event-per-turn inputs, field-upgradeable
firmware, and asset management data
reporting.

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3500/25 Enhanced Keyphasor Module
Datasheet 141532 Rev. T

Transducer Conditioning

Specifications

Minimum signal amplitude for

Inputs

Power
Consumption

Signal

Input
Impedance

Signal Conditioning

Speed/
Frequency
Signal
Ranges

Speed/
Frequency
Signal
Accuracy

Non­processed
Signals

Processed
Signals

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3.2 Watts typical

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
(NonIsolated 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).

21.8 k Ω minimum

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)

Specified at +25°C (+77°F).

0.017 to 100 Hz … ±1 cpm

101 to 500 Hz … ±8 cpm

501 to 20 kHz … ±1% of cpm

0.017 to 60 Hz … ±1 cpm

61 to 150 Hz … ±8 cpm

151 to 20 kHz … ±1% of cpm

Auto
Threshold

Manual
Threshold

Hysteresis User-selectable from 0.2 to 2.5 Volts.

Outputs

Buffered
Keyphasor
Signals

Output
Impedance

Keyphasor
Transducer
Power Supply

Front Panel LEDs

OK LED

TX/RX LED

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Environmental Limits

Operating
Temperature

Storage
Temperature

Humidity 95%, non-condensing

triggering is 2 volts peak to peak and
minimum frequency is 120 rpm (2
Hz).

Use for any input above 0.017 Hz (1
rpm for 1 event per revolution). User­selectable from 0 to -20 volts dc.
Minimum signal amplitude for
triggering is 500 millivolts peak to
peak.

Two buffered Keyphasor outputs are
available at the front of the rack via
coaxial connectors. Two buffered
Keyphasor outputs are also available
at the back of the rack via Euro Style
connectors.

504 Ω maximum buffered output
impedance.

-24 Vdc, 40 mA maximum per
channel.

Indicates when a fault has been
detected in the Keyphasor Module.

Indicates when the Keyphasor
Module is communicating with the
Rack Interface Module (RIM).

-30°C to +65°C (-22°F to +150°F)
when used with Keyphasor I/O
Module other than the Internal Barrier
version.

0°C to +65°C (32°F to +150°F) when
used with Keyphasor Internal Barrier
I/O Module (Internal Termination).

-40°C to +85°C (-40°F to +185°F)

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