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Power Testing (PWT)

The Power Test Module (PWT) and the hardware platform Distortion Analyzer (2 channels) or Power Monitor 8 (8 channels) allow to perform destructive testings of transducers with permanent monitoring of electrical, mechanical and thermal state variables and parameter variations. An external or internal generated excitation stimulus may be controlled in amplitude, spectral bandwidth or crest factor and may be supplied to the transducer permanently. The increase of the voice coil temperature can be measured by monitoring the electrical impedance of the speaker using a conventional AC-coupled amplifier (The mechanical parameters and the instantaneous displacement of a woofer can be monitored by impedance measurements dispensing with acoustical, mechanical or thermal sensors. The speaker parameters and state variables are sampled periodically and stored in a buffer in the hardware unit. Connecting a computer via USB to the hardware platform allows to view and investigate the destruction process in detail. This information is crucial for finding the physical cause of the failure and for understanding the temporal order of the destructive events. This enables the user to assess the maximal limits of the transducer more precisely.

  • Long term driver testing without sensor
  • High-speed temperature monitoring
  • Ideal for thermal parameter measurement
  • Full mechanical identification of woofers
  • Mechanical and thermal load versus time
  • Monitors destruction process
  • User defined failure limits
  • Measures up to 8 DUTs simultaneously
  • Stand-alone operation
  • Driver status displayed on hardware
  • Analysis of recorded measurement
  • Internal signal generator
  • Stimulus shaping/filtering
  • Any external signal (music)
  • Control of amplitude at terminals
  • Stepping amplitude
  • Cycle scheme (ON/OFF)

Specification

Products

PWT Lite 

was designed for traditional power testing, monitoring voltage, current, resistance and temperature.

PWT Pro 

also provides the "Woofer Identification" mode, which monitors the large signal parameters during the power test and helps finding the cause of defects. 

 

PWT Intermittend Summary Tool

provides a comprehensive summary of power test measurements, interrupted by cooling pauses and small signal measurements. 

PWT Intermittent Summary Tool

The PWT Intermittent Summery Tool provides a comprehensive summary of intermittent testing. Long-term monitoring tests are used to observe the loudspeaker parameter variation over a long measurement time (from hours to month) while using a natural audio stimulus (e.g. music) or an artificial test signal (e.g. noise). For monitoring of large signal parameters, this is done by on-line testing in the large signal domain using the normal power test stimulus. Monitoring of the small signal parameters requires intermittent testing by interrupting the power test and performing separate small signal measurements. A pause is included in the measurement to assure any transient effects from the large signal measurements have decayed (e.g. temperature).

Templates coming with the PWT module:

PWT 8 Woofers Param. ID Noise

Parameter Identification of Woofers using internal test signal (no cycling, no stepping)

PWT EIA accelerated life test

Accelerated life testing according EIA 426 B A. 4 using any external signal to monitor temperature, power and resistance

PWT IEC Long term Voltage

Power test to determine long-term maximal voltage according IEC 60268-5 paragraph 17.3 without parameter measurement for one device monitoring voltage, resistance, temperature and power

PWT IEC Short term Voltage

Power test to determine short term maximal voltage according IEC 60268-5 paragraph 17.2 without parameter measurement applied to 1 DUT monitoring temperature, power and resistance

PWT Powtest (fast Temp.)

Power test for fast monitoring of temperature, power and resistance without parameter measurement using external continuous signal (noise) supplied to IN1

PWT Powtest EXT. GENER.

Power test for monitoring temperature, power and resistance using external continuous signal (noise) supplied to IN1

PWT Powtest LIMITS

Power test to find maximal input voltage, power and temperature limits without parameter measurement applied to 1 DUT

PWT Powtest MUSIC

Power test without parameter measurement monitoring temperature, power, voltage and resistance using any external signal

PWT Powtest SWEEP

Power test for measuring the thermal time constant of the voice coil using sweep signal with low crest factor

PWT Powtest TIME Const.

Power test for measuring time constant of voice coil using internal test signal with cycling (ON/OFF phase)

PWT Woofer Param. ID MUSIC

Parameter Identification of Woofers
using external test signal (no ON/OFF cycling, no stepping)

PWT Woofer param. ID NOISE

Parameter Identification of Woofers
using internal test signal (no ON/OFF cycling, no stepping)

Read more

Paper: “Nonlinear Modeling of Heat Transfer”

Application Note AN18: “Measurement of Linear Thermal Parameters”

Application Note AN19: "Nonlinear Thermal Parameters Convection Cooling"

Application Note AN29: "Long Term Monitoring"


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