Celebrating 40 Years of Innovation: 1968-2008

Products: Electrostatic Voltmeter Instruments

Model 347 Electrostatic Voltmeter

The Trek Model 347 is a precision DC stable electrostatic voltmeter for making noncontacting surface voltage measurements in the range of 0 to ±3 kV DC or peak AC.  Industrial applications include surface voltage measurements of photoconductors or dielectric surfaces, charge monitoring in semiconductor production, or measuring electrostatic potentials on film, polymers, and paper.

The Model 347 employs a field-nulling technique for noncontacting voltage measurement that achieves DC stability and high accuracy even if the probe-to-surface spacing changes.   This permits measurements of either stationary or moving surfaces without the need to establish fixed spacing to maintain accuracy.

The Model 347 patented probe design, when compared to other probe designs, significantly improves noise and drift performance in the presence of contaminating particulates or under conditions of high humidity and wide temperature ranges.

The Digital Enable feature provides a connection for a remote device to turn on and off the internal high-voltage power supply.  This makes the Model 347 suitable for automated or computer-controlled systems.

A precision voltage monitor provides a low-voltage representation of the measured electrostatic potential for monitoring purposes, or for use as a feedback signal in a closed-loop system.

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PERFORMANCE

  • All specifications are with a 6000B-8 probe at a probe-to-surface separation of 2 mm.

    Measurement Range
    0 to ±3 kV DC or peak AC.

    Accuracy
    Voltage Monitor Output
    Better than ±0.05% of full scale.
    Voltage Display
    Better than ±0.1% of full scale referred to the voltage monitor.

    Speed of Response (10% to 90%)
    Less than 3 ms for a 1 kV step change.

    Stability
    Drift with Time
    Less than 100 ppm/hour, noncumulative.
    Drift with Temperature
    Less than 100 ppm/°C.

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PRODUCT FEATURES

  • Zero Control
    A multiturn control to produce zero volts output when the probe is coupled to a known zero volt surface.

    Response Control
    A ten position push-button switch that adjusts the gain of the Model 347 to optimize the AC response. The response control is normally adjusted when changing the type of probe being used or when changing the probe-to-surface separation.

    Voltage Monitor Output
    A buffered output providing a replica of the measured voltage.
    Scale(s)
    Model 347-3
    1/100th of the measured voltage.
    Model 347-15
    1/1000th of the measured voltage.
    Output Noise
    Less than 2 mV rms (measured using the true rms feature of the Hewlett Packard Model 34401A digital multimeter).
    Output Impedance
    Less than 0.1 ohm.

    Voltage Display
    3 3/4-digit LED display.
    Range
    0 to ±3000 V.
    Resolution
    1 V.
    Zero Offset
    Less than or equal to ±1 count.

    Digital Enable
    A TTL compatible input to turn on and off the internal high-voltage power supply. A TTL high (or open) will turn off the high-voltage. A TTL low will turn on the high-voltage.

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PROBE

Probe-to-Surface Separation (recommended)
2 mm ±1 mm.

Standard Resolution Probes
Model 6000B-7C  end-viewing, round body.
Model 6000B-8  side-viewing, round body.
Model 6000B-15C  end-viewing, square body.
Model 6000B-16  side-viewing, square body.

High Resolution
Model 6000B-5C  end-viewing, round body.
Model 6000B-6  side-viewing, round body.
Model 6000B-13C  end-viewing, square body.
Model 6000B-14   side-viewing, square body.

Miniature
Model 555P-4  end-viewing, square body.
Model 555P-1  side-viewing, square body.

High Temperature (up to 100 °C)
Model 6300-7  end-viewing, square body.
Model 6300-8  side-viewing, square body.

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ACCESSORIES

  • Accessories Supplied
    • Operator’s manual and line cord.
  • Optional
    • 603RA Full-Rack Mounting Kit
      604RA 1/2-Rack Mounting Kit

      6003B Probe Line Driver (required when a very long probe extension cable is used)*

      6004B-EC Probe Extension Cable (from 347 to line driver)*

      6005B-EC Probe Extension Cable (from 347 to probe)*


      CE Compliance standards are not guaranteed with the use of these accessories.

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GENERAL

  • Line Supply
    Factory set for one of two ranges: 90 to 127 V AC or 180 to 250 V AC, at 48 to 63 Hz
    (specify when ordering).

    Operating Conditions
    Temperature
    0°C to 40°C.
    Relative Humidity
    To 90%, noncondensing.

    Dimensions
    108 mm H x 223 mm W x 357 mm D
    (4.25" H x 8.75" W x 14"D).

    Weight
    3 kg (6.6 lb).

    Voltage Monitor Connector
    BNC coaxial connector.

    Digital Enable Connector
    BNC coaxial connector.

    Ground Receptacle
    Banana jack.

    AC Line Cord Receptacle
    Standard three-prong line cord receptacle with an integral power switch and fuse holder.

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CERTIFICATION

TREK, INC. certifies that each Model 347 is tested and calibrated to specifications using measurement equipment traceable to the National Institute of Standards and Technology or traceable to consensus standards. A Certificate of Calibration accompanies each instrument when it is shipped from the factory.
Low Voltage Safety Compliance
(EN 61010-1)
Overvoltage Category
CAT II: Local-level mains, appliances, portable equipment.
Pollution Category
Degree 1: Operate in environments where no pollution or only dry nonconductive pollution occurs.

Copyright © 2004 TREK, INC.  All specifications are subject to change.

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