Fluke 99B Telescope User Manual


 
Measuring Examples 7 - 9
MEASURING THREE-PHASE ON A DUAL
INPUT
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
CIRCUIT 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.