BRUEL & KJAER 2732 - User Manual

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Summary

Safety Considerations

Safety Symbols

Symbols used in the manual for important safety information.

Explosion Hazard

Warning regarding operation in potentially explosive environments.

General Warnings

Important safety warnings for operation and maintenance.

Controls

Front Panel Controls

Description of controls and indicators on the front panel.

Back Panel Connections

Overview of input/output sockets and connectors on the back panel.

Operation

Environment and Mounting

Operational environment, temperature, and mounting options.

System Connections

Procedures for system checks and making connections to exciters.

Mains Supply and Fuse Handling

Instructions for mains supply connection and fuse management.

Mains Socket Connection

Details on connecting the mains power cable.

Operating Procedure

Step-by-step guide for operating the amplifier.

Warning Lamps and Fault Detection

Interpretation of warning lamps and fault diagnosis.

Characteristics

Signal Inputs

Details on signal inputs, impedance, and frequency response.

Power Output Modes

Describes output characteristics in Voltage and Current modes.

Frequency Response and Distortion

Specifies frequency response curves and harmonic distortion levels.

Specifications

General and Environmental Specs

Standards, safety, environmental, and mechanical properties.

Performance Characteristics

Key performance metrics: power, frequency, distortion, impedance, gain.

Controls, Indicators, and Display

Amplifier controls, status indicators, and LCD display features.

Protection and Features

Protection mechanisms, peak current limiting, and other features.

Physical Dimensions and Weight

Physical size, weight, and mounting details.

Monitor Output Specs

Details on monitor output signal characteristics.

The Brüel & Kjær Type 2732 Power Amplifier is a robust and versatile instrument designed primarily for driving vibration and modal exciters, such as the Modal Exciter Type 4824. It can also be used with any exciter requiring a 120 VA power amplifier.

Function Description:

The Type 2732 serves as a power amplifier, providing a rated AC output of 120 VA into a 4 Ω exciter or resistive load. It offers a usable frequency range from 40 Hz to 15 kHz at full capacity, and from DC to 150 kHz at reduced capacity. The amplifier is designed for excellent stability, tolerating temperature and supply-line variations. It can operate as either a voltage generator with low output impedance and a flat voltage frequency response, or as a current generator with high output impedance and a flat current frequency response. The RMS output-current limit is adjustable, and heavy negative feedback ensures very low harmonic content in the output.

Important Technical Specifications:

Power Output Capacity: 120 VA into a 4 Ω exciter or resistive load (at 25°C and nominal mains voltage).
Output Voltage Capacity: 22 V RMS, DC to 15 kHz (without load).
Output Current Capacity: 5.5 A RMS (40 Hz to 15 kHz), 5.0 A RMS (15 Hz to 15 kHz).
Max. Voltage Gain: 17 dB ±2 dB @ 1 kHz.
Frequency Range:
- Full Capacity: 40 Hz to 15 kHz.
- Reduced Capacity: DC to 150 kHz (-20 dB).
Frequency Response (Typical small signal response, -20 dB, low impedance mode):
- DC Input: DC to 15 kHz ±0.5 dB; DC to 150 kHz ±3 dB.
- AC Input: 15 Hz to 15 kHz ±0.5 dB.
Harmonic Distortion (120 VA in a 4 Ω load):
- Voltage Mode (Low Impedance): <0.1% (40 Hz to 5 kHz), <0.2% (5 kHz to 15 kHz).
- Current Mode (High Impedance): <0.2% (40 Hz to 2 kHz), <0.8% (2 kHz to 15 kHz).
Input Impedance: >10 kΩ.
DC Stability: Less than ±100 mV drift from 0V for ±10% variation of mains supply from nominal, and for 10°C to 40°C (50°F to 104°F) variation in ambient temperature.
Power Requirements: Single phase 100, 120, 230 V RMS, ±10%, 50 – 60 Hz. Approx. 230 VA at full load.
Fuses: T6.3A slow blow for 100 V or 120 V; T2.5A slow blow for 230 V.
Dimensions:
- Height: 2HE (88 mm / 3.5 in.).
- Width: 482.6 mm (19 in.) with flanges for standard 19 in. rack mounting.
- Depth: 450 mm (13.8 in.).
Weight: 14 kg (31 lb).
Monitor Output (5 Hz to 15 kHz):
- Voltage: 0.1 V/V ±3%.
- Current: 0.1 V/A ±3%.
Operating Temperature: +5 to +40°C (41 to 104°F).
Storage Temperature: -25 to +70°C (-13 to 158°F).
Humidity: 90% RH (non-condensing at 40°C (104°F)).

Usage Features:

Front Panel Controls:
- Power: Mains On/Off push-button switch.
- Display: LCD shows output AC current and voltage.
- Variable Gain (dB): Single-turn, logarithmic potentiometer for continuous adjustment of input signal level. Turning fully anticlockwise past the click and back again activates reset.
- Current Limit A (RMS): Single-turn potentiometer for limiting RMS current output (1 to 5.5 A).
- Phase: Push-button switch to set output/input phase shift (0 or 180 degrees).
- V/C Mode: Push-button switch for selection of feedback and output-impedance modes (Voltage Mode for constant voltage/low output impedance, Current Mode for constant current/high output impedance).
Indicator Lamps (LEDs):
- State: Green when amplifier power is on.
- Output Phase: Green when indicating phase shift.
- Distortion: Yellow when output voltage or current clipping occurs.
- Temperature: Red if Power MOS Output Transistors overheat (puts amplifier in Reset State).
- Current: Red when output current exceeds limit (puts amplifier in Reset State).
- Output V/C Mode: Green, showing selected output mode.
- Interlock: Red when interlock circuit is activated.
Back Panel Connections:
- Signal Input DC: BNC socket for direct-coupled input, enabling DC offset for exciter armature centering.
- Signal Input AC: BNC socket for capacitive-coupled input.
- Output: 4-pin Neutrik® Speakon® socket for exciter connection.
- Mains Voltage Selector and Fuse: Selects 100, 120, or 230 V operation and houses the mains fuse.
- Mains Input: Socket for power cable.
- Mains Output: Socket for DC Static Centering Unit Type 1056 (optional).
- Voltage Monitor: BNC socket providing attenuated (0.1 V/V) amplifier output voltage waveform for oscilloscope display.
- Current Monitor: BNC socket providing attenuated (0.1 V/A) amplifier output current waveform for oscilloscope display.
Rack Mounting: Designed to fit into a 19-inch standard rack system (with rubber feet removed) or can be used free-standing.

Maintenance Features:

Safety Considerations: Designed and tested in accordance with IEC 61010-1 and EN 61010-1. Warnings and safety symbols are provided in the manual.
Overheating Protection: The input drive signal is automatically blocked, and the amplifier enters a Reset State if Power MOS Output Transistors overheat, ensuring protection. Adequate cooling air flow through the front and back vents is crucial.
Fault Detection: Red warning lamps indicate system faults (e.g., input drive level too high, wrong output connections, overdrive, high temperature, blocked air cooling). The system automatically stops to protect the amplifier and exciter.
Fuse Replacement: Mains fuse is easily accessible beneath the voltage selector. Specific fuse ratings are provided for different mains voltages.
Service and Repair: The device is designed for safe and reliable operation. In case of impaired function or safety, it should be immediately disconnected from the mains. Repairs should only be attempted by qualified service personnel or a Brüel & Kjær service representative.