Bently Nevada 3500/70M Data sheet

3500/70M Recip Impulse Velocity Monitor

Datasheet

Bently Nevada Machinery Condition Monitoring

Description

The 3500/70M Recip Impulse Velocity Monitor is a 4-channel device used as part of the reciprocating compressor solutions package to monitor compressor crankcase and crosshead vibration. The monitor accepts input from seismic transducers, conditions the signal to derive vibration measurements, and compares the conditioned signals with user-programmable alarms.

You can program each channel using the 3500 Rack Configuration Software to perform the following functions:

l Impulse Acceleration l Acceleration 2 l Recip Velocity l Low Frequency Recip Velocity

The monitor channels are programmed in pairs and can perform up to two of the aforementioned functions at a time. For example, channels 1 and 2 can perform one function while channels 3 and 4 perform another or the same function.

166766 Rev. M

The primary purpose of the 3500/70M Recip Impulse Velocity Monitor is to provide the following:

l Machinery protection for reciprocating compressors by

continuously comparing monitored parameters against configured alarm setpoints to drive alarms

l Essential reciprocating compressor machine

information for both operations and maintenance personnel

Each channel, depending on configuration, typically conditions its input signal to generate various parameters called static values. You can configure alert setpoints for each active static value and danger setpoints for any two of the active static values.

3500/70M Recip Impulse Velocity Monitor Datasheet 166766 Rev. M

Impedance

Specifications

Inputs

Signal

Input impedance

Special inhibit

Power consumption

Sensitivity

Impulse acceleration

Acceleration 2

Recip velocity

Low Frequency Recip velocity

Accepts from 1 to 4 proximity probe signals.

10 kΩ acceleration input >1 MΩ velocity input

Contact closure 5 Vdc @ 390μA typical

7.7 watts, nominal

0.51 – 11.72 mV/(m/s2) 5 – 115 mV/g

3.54 – 22.64 mV/(mm/s) 90 – 575 mV/(in/s)

Protection

Recorder Outputs

Recorder

Voltage compliance

Load resistance 600 Ω maximum Resolution 0.3662 µA maximum Update rate <100 millisecond

Accuracy

Signal Conditioning

Specified at +25 ºC (+77 ºF) unless otherwise noted.

Each connector is short-circuit protected.

+4 to +20 mA proportional to monitor full-scale. Selects one static data value from each channel to be used for that channel’s recorder value.

+12 Vdc maximum

Within ±0.05 mA. ±0.14 mA over temperature range.

Outputs

Front Panel LEDs

Indicates when the 3500/70M

OK LED

TX/RX LED

Bypass LED

Transducer Power Supply

Voltage -22 Vdc minimum

Current

Output impedance

Protection

Front Panel Buffered Outputs

Buffered Transducer Outputs

Output

Recip Impulse Velocity Monitor is operating properly.

Indicates when the 3500/70M Recip Impulse Velocity Monitor is communicating with other modules in the 3500 rack.

Indicates when the 3500/70M Recip Impulse Velocity Monitor is in Bypass Mode.

40 mA maximum 15 mA maximum on startup to guarantee no fold back

20 Ω typical operating 1000 Ω typical under fold back conditions

Foldback current

15.4 to 24.9 mA

The front of each monitor has one coaxial connector for each channel.

550 Ω typical

Impulse Acceleration

Within ± 0.33% of full-scale

Accuracy

Band start

Band duration

Frequency Response

Bias filter

Not OK filter

Static values

Filter Quality

High-pass

Low-pass

typical,

± 1% maximum Exclusive of filters

0 to 359° 1° resolution

1 to 360° 1° resolution

-3 dB at 0.01 Hz 1-pole Low-Pass

-3 dB at 2400 Hz 1-pole Low-Pass

Smoothing filter 8-revolution average value

4-pole 80 dB per decade 24 dB per octave

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3500/70M Recip Impulse Velocity Monitor Datasheet 166766 Rev. M

Corner

Selection

High-pass 3 - 3000 Hz 10 - 3000 Hz

Low-pass 30 - 30000 Hz 40 - 30000 Hz

Peak 3 dB

Corner

RMS 3 dB

Corner

Acceleration 2

Within ± 0.33% of full-scale

Accuracy

Frequency Response

Bias filter

Not OK filter

Peak static values

RMS static values

Filter Quality

High-pass

Low-pass

Corner

Selection

High-pass

Low-pass

typical ± 1% maximum Exclusive of filters

-3 dB at 0.01 Hz 1-pole Low-Pass

-3 dB at 2400 Hz 1-pole Low-Pass

-3 dB at 0.3 Hz 1-pole Low-Pass

-3 dB at 0.1 Hz 1-pole Low-Pass

4-pole 80 dB per decade 24 dB per octave

Pk 3 dB

Corner

3 - 3000 Hz10 - 3000

30-30000 Hz

RMS 3 dB

Corner

40 30000 Hz

Integrate

3dB

Corner

3-3000 Hz

40-20000 Hz

Recip Velocity

Accuracy

Velomitor

Frequency Response

Bias filter

Not OK filter

Integration filter

RMS static values

Peak static values

1X & 2X Vector Filter

Filter Quality

High-pass

Low-pass

Corner

Selection

Pk 3 dB

Corner

Within ± 0.33% of full-scale typical ± 1% maximum Exclusive of filters

Additional accuracy degradation occurs when full scale signal levels are low: Full Scale 0-0.5: ±3% typical Full Scale 0-1.0: ±2% typical Full Scale 0-2.0: ±1% typical

-3 dB at 0.01 Hz 1-pole Low-Pass

-3 dB at 2400 Hz 1-pole Low-Pass

-3 db at 0.34 Hz 1-pole Low-Pass

-3 dB at 0.1 Hz 1-pole Low-Pass

-3 dB at 0.3 Hz 1-pole Low-Pass

Constant Q filter with bandwidth = ±3% running speed Q = 16.7

4-pole 80 dB per decade 24 dB per octave

2-pole 40 dB per decade 12 dB per octave

RMS 3 dB

Corner

Integrate

3dB

Corner



High-pass 1- 400 Hz 10-400 Hz 3-400 Hz

Low-pass

40-5500 Hz

60-5500 Hz

40-5500 Hz



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3500/70M Recip Impulse Velocity Monitor Datasheet 166766 Rev. M

Low Frequency Recip Velocity

Within ± 0.33% of full-scale

Accuracy

Velomitor

Frequency Response

Bias filter

Not OK filter

Integration filter

RMS static values

Peak static values

1X & 2X Vector Filter

Filter Quality

High-pass

Low-pass

Corner

Selection

High-pass 0.750 - 100 Hz 0.750 - 100 Hz

Low-pass 10 - 1375 Hz 15 - 1375 Hz

typical ± 1% maximum Exclusive of filters

Additional accuracy degradation occurs when full scale signal levels are low: Full Scale 0-0.5: ±3% typical Full Scale 0-1.0: ±2% typical Full Scale 0-2.0: ±1% typical

-3 dB at 0.01 Hz 1-pole Low-Pass

-3 dB at 2400 Hz 1-pole Low-Pass

-3 db at 0.34 Hz 1-pole Low-Pass

-3 dB at 0.1 Hz 1-pole Low-Pass

-3 dB at 0.3 Hz 1-pole Low-Pass

Constant Q filter with bandwidth = ±3% running speed Q = 16.7

4-pole 80 dB per decade 24 dB per octave

2-pole 40 dB per decade 12 dB per octave

Peak and

Integrate 3dB

Corner

RMS 3 dB

Corner

Rack Space Requirements

Monitor 1 full-height front slot I/O Modules 1 full-height rear slot

Physical

Monitor Module (Main Board)

Dimensions (Height x Width x Depth)

Weight 0.91 kg (2.0 lb)

I/O Modules (non-barrier)

Dimensions (Height x Width x Depth)

Weight 0.20 kg (0.44 lb)

I/O Modules (barrier)

Dimensions (Height x Width x Depth)

Weight 0.46 kg (1.01 lb)

241.3 mm x 24.4 mm x 241.8 mm (9.50 in x 0.96 in x 9.52 in)

241.3 mm x 24.4 mm x 99.1 mm (9.50 in x 0.96 in x 3.90 in)

241.3 mm x 24.4 mm x 163.1 mm (9.50 in x 0.96 in x 6.42 in)

Alarms

Use Rack Configuration Software to set alert levels for each value measured by the monitor and danger setpoints for any two of the values measured by the monitor.

Alarm Setpoints

Accuracy of alarm setpoints

Alarm Time Delays

You can program alarm delays using 3500 Rack Configuration Software.

Alarms are adjustable from 0 to 100% of full-scale for each measured value. However, when the full-scale range exceeds the range of the transducer, the range of the transducer will limit the setpoint.

Within 0.13% of the desired value

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Alert

Danger

From one to 60 seconds in one second intervals

0.1 seconds (nominal) or from one to 60 seconds in one second intervals

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