Monroe Electronics Electrostatic Voltmeter - Isoprobe® - model 244A - Manual (Page 7)

7
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
Vi psi (14" w.c.). All
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.
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.