Measuring Three-Phase On A Dual Input - Fluke 91 Series II User Manual

Measuring Examples
MEASURING THREE-PHASE ON A DUAL
INPUT
91
Dual input measurements can be used for many applica-
tions. This example shows how to use these measure-
ments to determine phase rotation of a "Y" connected
three-phase system at a load center. Use alligator clips to
connect the ScopeMeter test tool to the three-phase sys-
tem connections.
Figure 7-8 Testing a Three-Phase System
WARNING
THE SETUP REQUIRES CONNECTING TEST LEADS
TO LIVE COMPONENTS OF A HIGH ENERGY CIRCUIT.
TO AVOID ELECTRIC SHOCK AND/OR EQUIPMENT
DAMAGE, USE CAUTION WHEN CONNECTING ALLI-
GATOR CLIPS TO LIVE COMPONENTS.
THE METAL JAWS OF ALLIGATOR CLIPS CAN CRE-
ATE A SHORT CIRCUIT BETWEEN CLOSELY SPACED
LIVE PARTS. AVOID MAKING CONNECTIONS TO
FEEDER CONDUCTORS OR BUS BARS AT ELEVATED
POTENTIALS. WHENEVER POSSIBLE, MAKE CON-
NECTIONS TO THE OUTPUT SIDE OF A CIRCUIT
BREAKER WHICH CAN PROVIDE BETTER SHORT CIR-
CUIT PROTECTION.
MAKE CONNECTIONS TO CIRCUIT BREAKERS BY
FIRST TURNING THE CIRCUIT BREAKER OFF. THEN
CONNECT THE ALLIGATOR CLIP TO THE BREAKER
OUTPUT TERMINAL VIA A SHORT PIECE OF INSU-
LATED WIRE AS SHOWN IN FIGURE 7-9.
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