Vanguard Auto-Ohm 100_200 s2 - Manual (Page 19)

AUTO-OHM 100/200 Series 2 Operating Procedures
19
Rev 3, 2009
6.0 OPERATING THE AUTO-OHM
The Auto-Ohm is operated with one dual-function control knob. The operator turns the control
knob to scroll through different menu selections on the display. When the desired option appears,
it is selected by pressing the control knob like a pushbutton. Review Figure 12.0 before
proceeding with the step-by-step procedures that follow.
6.1 Step-by-Step Procedures
The following sections present step-by-step procedures for the operation of the Auto-Ohm 100
and Auto-Ohm 200 Series 2.
6.2 Precautions
Do not measure the resistance of inductive devices. This can generate unsafe high-voltage spikes
(created by a collapsing magnetic field) if the test current is interrupted by detaching a test lead
during a test. Do not touch or disconnect any test lead that is connected to a device under test
while current is being conducted. Failure to heed this warning can result injury to the user
and/or damage to the Auto-Ohm. The Auto-Ohm measures low, non-inductive resistances
(e.g., breaker contacts and bus-bar junctions). If the resistance of an inductive device needs to be
measured, then the use of an instrument designed for that purpose is recommended (such as the
WRM made by the Vanguard Instruments Company).
6.3 Preparations
a. Ground Auto-Ohm to Substation ground.
b. Plug the Auto-Ohm power cable into a power outlet.
c. Connect current-cable lugs and voltage-sensing cable plugs to control-panel (Figure 6.0 and
Figure 7.0).
d. Attach current test-cable clamps to opposite terminals of the resistive load being tested (Figure
8.0 to Figure 11.0).
e. If separate cables are used, attach voltage-sensing clamps to the terminals of the resistive load.
Sensing voltage clamps should be inside the current clamps.
f. To turn on Auto-Ohm power, press the rocker switch to ON.
NOTE
All Auto-Ohm operations begin at the MAIN MENU, which appears after the initial
boot-up (after configuration and software revision data display briefly.) The Main
Menu display is shown below.
Figure 13.0 Main Menu
g. The main menu displays a list of four options, which appear in sequence as the control knob is
turned. The four options of the MAIN MENU list are RUN TEST, ADJ CONTRAST, 100A
CAL. CHECK, and PREVIOUS RESULTS.
MAIN MENU
<RUN TEST>