Vanguard DMOM-100_200 s2 - Manual (Page 19)

DMOM-100/200 Series 2 Operating Procedures
19
Rev 2, 2009
7.0 OPERATING PROCEDURES
7.1 Step-by-Step Procedures
Review Figure 14.0 before proceeding with the step-by-step procedures that follow.
7.2 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 testing is being conducted. Failure to heed this warning can cause injury to the user
and/or damage to the DMOM. The DMOM 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).
7.3 Preparations
a. Ground the DMOM to the Substation ground.
b. Plug the DMOM power cable into a power outlet.
c. Connect the current-cable lugs and voltage-sensing cable plugs to the control-panel (Figure
6.0 and Figure 7.0).
d. Attach the 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 the voltage-sensing clamps to the terminals of the resistive
load. The sensing voltage clamps should be inside the current clamps.
f. Turn on the DMOM’s power, by pressing the rocker switch to ON.
7.4 Operating Overview
Procedures for operating the DMOM are presented in tabular format, with a different table for
each of the operations available. All operations are described in step-by-step sequences. Each
step is indexed by number and indicates an operator action, followed by a description or
illustration of what should be observed on the DMOM display to confirm the action. All
operations begin with the START menu (shown below):
Figure 12.0 The START Menu
Item 1 (RUN TEST) is a menu of functions and options available for measuring an unknown
resistance. Item 2 (SETUP) is for record manipulation in the DMOM. Item 2 (SETUP) expands
into a menu of support functions. Item 3 (CAL CHECK) is a performance-verification operation
for checking key circuit functions.
1. RUN TEST 12/11/08
2. SETUP 12:25:00
3. CAL CHECK