Monroe Electronics 244A User Manual

Instruction Manual

for

Monroe Electronics, Inc.

Isoprobe® Electrostatic Voltmeter

Model 244A

Specifications subject to change without notice.

P/N 0340074

053013

100 Housel Ave  PO Box 535  Lyndonville NY 14098 Fax: 585-765-9330 monroe-electronics.com

114

TABLE OF CONTENTS

2. BEWARE: HIGH VOLTAGE ........................................ PAGE 4

5. CONTROLS AND INDICATORS ................................. PAGE 10

APPENDIXES:

MODEL 1017 PROBE MOUNTING .......................................... APPENDIX I

10X GAIN MODIFICATION ...................................................... APPENDIX II

MODEL 1017 PROBE CLEANING PROCEDURES ................. APPENDIX III

MODELS 1017E/22D AND 1017S/22D GRADIENT

ADAPTERS .............................................................................. APPENDIX IV

WARRANTY AND RETURN ....................................... PAGE 3

SPECIFICATIONS ...................................................... PAGE 5

INSTALLATION ........................................................... PAGE 7

OPERATION ............................................................... PAGE 13

THEORY ..................................................................... PAGE 15

WARRANTY

Monroe Electronics, Inc., warrants to the Owners, this instrument to be free from defects in material and workmanship for a period of two years after shipment from the factory. This warranty is applicable to the original purchaser only.

Liability under this warranty is limited to service, adjustment or replacement of defective parts (other than tubes, fuses or batteries) on any instrument or sub-assembly returned to the factory for this purpose, transportation prepaid.

This warranty does not apply to instruments or sub-assemblies subjected to abuse, abnormal operating conditions, or unauthorized repair or modification.

Since Monroe Electronics, Inc. has no control over conditions of use, no warranty is made or implied as to the suitability of our product for the customer’s intended use.

THIS WARRANTY SET FORTH IN THIS ARTICLE IS EXCLUSIVE AND IN LIEU OF ALL OTHER WARRANTIES AND REPRESENTATIONS, EXPRESS, IMPLIED OR STATUTORY INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. Except for obligations expressly undertaken by Monroe Electronics, in this Warranty, Owner hereby waives and releases all rights, claims and remedies with respect to any and all guarantees, express, implied, or statutory (including without limitation, the implied warranties of merchantability and fitness), and including but without being limited to any obligation of Monroe Electronics with respect to incidental or consequential damages, or damages for loss of use. No agreement or understanding varying or extending the warranty will be binding upon Monroe Electronics unless in writing signed by a duly authorized representative of Monroe Electronics.

In the event of a breach of the foregoing warranty, the liability of Monroe Electronics shall be limited to repairing or replacing the non-conforming goods and/or defective work, and in accordance with the foregoing, Monroe Electronics shall not be liable for any other damages, either direct or consequential.

RETURN POLICIES AND PROCEDURES FACTORY REPAIR

Return authorization is required for factory repair work. Material being returned to the factory for repair must have a Return Material Authorization number. To obtain an RMA number, call 585- 765-2254 and ask for Customer Service.

Material returned to the factory for warranty repair must be accompanied by a copy of a dated invoice or bill of sale, which serves as a proof of purchase for the material.

Repairs will be returned promptly. Repairs are normally returned to the customer by UPS within ten working days after receipt by Monroe Electronics, Inc. Return (to the customer) UPS charges will be paid by Monroe Electronics on warranty work. Return (to the customer) UPS charges will be prepaid and added to invoice for out-of-warranty repair work.

EXPEDITED FACTORY REPAIR:

All material returned to the factory by air or by an overnight service will be expedited. Expedited factory repairs will be returned to the customer by the same mode of transportation by which the material was returned to the factory for repair (i.e., material returned to the factory by an overnight service will be returned to the customer by an overnight service). NOTE: Return (to the customer) transportation expenses for expedited factory repairs will always be at the expense of the customer despite the warranty status of the equipment.

FACTORY REPAIRS TO MODIFIED EQUIPMENT:

Material returned to the factory for repair that has been modified will not be tested unless the nature and purpose of the modification is understood by us and does not render the equipment untestable at our repair facility. We will reserve the right to deny service to any modified equipment returned to the factory for repair regardless of the warranty status of the equipment.

BEWARE - - HIGH VOLTAGE

GENERAL:

Monroe Electronics ISOPROBE instruments are non- contacting voltage followers. This means an instrument indicating 1500 volts has its probe operating at 1500 volts off ground.

If it is accidentally touched, the probe will apply VERY BRIEFLY 1500 volts to the unwary participant.

Typically, a spark will jump which will be disturbing but not hazardous electrically, (but you could recoil from the surprise and hurt yourself.)

SHORT CIRCUIT CURRENT:

The short circuit current that can be delivered by an ISOPROBE Voltmeter is limited to approximately 500 feeling for most people and therefore is clearly no hazard.

which is below the threshold of

STORED ENERGY:

The high voltage spark is caused by the discharge of the capacitance of the system through the body. This stored energy is typically in the order of a few millijoules while the lethal level of stored energy has been approximated at 27 joules.

A safety factor of better than 1000:1 therefore exists.

ALTHOUGH THE SPARK IS CLEARLY ANNOYING, IT WON'T HARM YOU UNLESS YOU OVERREACT.

MONROE ELECTRONICS, INC. LYNDONVILLE, NEW YORK 14098

A. APPLICATIONS:

The Model 244A instrument permits accurate voltage measurements of electrostatic or other high impedance sources without physical contact. It utilizes an electrostatic chopper for low drift, and negative feedback for accuracy and probe-to-surface spacing insensitivity.

B. FEATURES:

■ Integrated Solid State Circuitry

■ Good Accuracy

Stability Reliability

■ Easy Maintenance

■ ±3kV Input Range

■ Fast Speed-of-Response

SECTION 1

SPECIFICATIONS

■ Specified AC Performance

■ Low Noise

■ Digital Liquid Crystal Display

■ HV/1000 Recorder Output

■ Connectable for unlimited multiple channel operation

C. RANGE: 0 to ±3000 volts DC.

D. STATIC ACCURACY:

The recorder output accuracy referred to the input is better than 0.10% of reading or 0-1V whichever is greater. (Probe-to-surface spacing .020”, 0.5mm).

E. SPEED-OF-RESPONSE:

10-90% probe-to-surface spacing .040" (1.02mm), gain adjusted for critical damping.

Speed of Response typ. max.

1kV Step .......................................... 1.5 msec ................. 2.5 msec

2kV Step .......................................... 2.0 msec ................. 3.5 msec

3kV Step .......................................... 3.0 msec ................. 4.5 msec

F. SETTLING TIME:

typical - 3.5msec. 0-99% 1kV step, 040"(1.02mm) gain adjusted for critical

damping.

15 msec. 0-99.9% 1kV step, .040"(1.02mm)

G. FREQUENCY RESPONSE:

Small signal bandwidth is related to amplitude. At 11 5 volts RMS bandwidth is

typically -3db at 300 Hz.

H. DRIFT:

Drift is specified with 1017S or E probes at .005" (.13mm) probe-to-surface

spacing, purged in a clean stable atmosphere.

Less than 0.01 V/hr. non-cumulative after 1 hr. warm-up in an uncontaminated atmosphere.

Indiscernible effects of line voltage variations, 10 to 90% relative humidity,

15°C to 35°C temperature range.

I. NOISE (Referred to Input):

Probe-to-surface spacing = .005" (.13mm), 1017S or E probe 600 mV RMS or 2V

p-p wideband typical. See graphs for other aperture or probe-to-surface

spacings. Also check individual probe specifications.

J. SURFACE RESOLUTION:

Surface resolution is dependent upon probe aperture size and probe-to-surface

spacing. Refer to probe literature for specific information relative to probe being

used.

K. PROBE-TO-SURFACE SPACING ERRORS:

Independent balance and zero adjustments allow voltage readings independent

of probe-to-surface spacing. The stability of these adjustments relates to the

same factors as does drift.

L. METER:

Four digit auto-zero, auto-symmetry, auto-polarity meter, with a liquid crystal

readout.

M. RECORDER OUTPUT:

A low voltage HV/1000 output is provided with a 3V max. output. The output is

capable of driving 10000 or greater.

N. POWER INPUT:

100, 117 or 230 volts ±10%, 50/60 Hz., 15 watts max.

O. PROBE DIMENSIONS:

Model 1017 series probes are 0.35" (8.9mm) x .35" (8.9mm) x 2.85" (72.4mm);

weight 6% oz. (180 gm).

P. SIZE AND WEIGHT):

Size 4" (10.2cm) high x

oz. (3.26kg.).

8^/ 2"

(21.6cm) wide x 15" (38.1 cm) deep. Weight 7 lbs. 3

SECTION 2

INSTALLATION

CAUTION:

Before plugging instrument in, make certain that it is matched to local power line voltage. The factory set line voltage is indicated on a label directly below the power connector and in the small window in the fuse drawer.

In the event that it is desired to change the operating voltage of the instrument (or inspect or replace the fuses), squeeze the tab on the drawer and remove the drawer. Slide the square insert out of the drawer, replace the fuse with the correct value and orient the insert so that the desired line voltage shows through the window. Replace the drawer in the power connector. CHANGE THE LABEL TO CORRESPOND. All units are shipped wired for 115 VAC unless otherwise specified.

NOTE:

Wire Color Code For Line Cord Provided.

HIGH SIDE OF LINE - BLACK or BROWN

LOW SIDE OF LINE - WHITE or LIGHT BLUE

SAFETY GROUND - GREEN or GREEN/YELLOW

A. PROBE PURGING:

Probe purging improves instrument performance especially with regard to zero stability, noise and sensitivity to variations in probe-to-surface spacing. Optional Model 1017/22G purge kit available from Monroe Electronics maintains an even air flow, reduces temperature variations and filters out dust and other particles.

Contact potential is a function of these variables and should be considered when making any changes in the purging techniques. Care should be taken to maintain the purged air as free from chemical vapor contamination as possible.

Probes may also be purged using clean, dry oil-free air from a local source or through the use of dry nitrogen or other inert gas. Pressure needs only be sufficient to maintain a positive flow of gas out of the sensitive aperture to prevent foreign materials from entering and, in no case should it exceed materials used should have low out-gassing properties.

For best results, leave purge in continuous operation. For long term storage, cover the end of the probe with the plastic cap supplied or with aluminum foil to seal against contamination.

B. MOUNTING:

The 1017 and all other compatible probes must be mounted with the sensitive aperture facing the surface to be measured.

psi (14" w.c.). All

The probe must be electrically isolated for up to 3400V, since the probe acquires the potential of the surface being measured.

Further probe mounting information is given in Appendix I.

C. PROBE-TO-SURFACE SPACING:

CAUTION:

When operating at probe-to-surface spacing of less than 0.125 inches (3mm) -BEWARE OF PROBE-TO-SURFACE ARC-OVER.

Air is subject to dielectric breakdown when the probe-to- surface spacing is low and the surface voltage is high. A destructive arc-over can occur damaging the surface under test and/or the sensitive circuitry of the probe.

REFER TO FIGURE 2-1 TO DETERMINE THE SAFE PROBE-TO-SURFACE SPACING FOR A GIVEN UNKNOWN VOLTAGE.

Probe to surface spacing should be maintained as close as physically reasonable for best performance. Typical spacing range is from .005" (0.1mm) for unknown voltages below 500 volts to over .125" (3mm) for unknown voltages up to 3000 volts.

As probe to surface spacing increases instrument performance will suffer:

1. Decreased Accuracy

2. Decreased Speed-of-Response

3. Decreased Surface Resolution

4. Increased Noise

5. Increased Drift

ARC BR EAKDO W N VS. P RO BE-T O-SURF AC E SPAC IN G

TYP. BREAKDOWN TEST DATA • = SIDE VIEWING

PROBE-TO-SURFACE SPACING

FIGUR E 2-1

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