2-2
Power Distribution
Delta / Delta with Grounded Leg
or Four-Wire Connected Secondary Delta
Delta / Delta with Grounded Leg or Four-Wire Connected Secondary Delta
is a common configuration providing voltage re-balancing with no phase
shift between input and output. The grounded center tap provides a direct
path for common mode current caused by the drive output.
3-Phase Open Delta with 1-Phase Center Tapped
Three-Phase Open Delta with 1-Phase Center Tapped is a configuration
providing a 3-phase delta transformer with one side tapped. This tap (the
neutral) is connected to earth. The configuration is called the antiphase
grounded (neutral) system.
The open delta transformer connection is limited to 58% of the 240V,
single-phase transformer rating. Closing the delta with a third single-phase,
240V transformer allows full rating for the two single-phase, 240V
transformers. The phase leg opposite the midpoint has an elevated voltage
when compared to earth or neutral. The “hottest” high leg must be
positively identified throughout the electrical system. It should be the center
leg in any switch, motor control, three-phase panel board, etc. The NEC
requires orange color tape to identify this leg.
or
Three
Phase
Loads
Single Phase Loads
Single Phase Loads
Summary of Contents for Allen-Bradley 1305-AA02A
Page 4: ...ii Summary of Changes Notes ...
Page 40: ...2 18 Power Distribution Notes ...
Page 48: ...3 8 Grounding Notes ...
Page 68: ...4 20 Practices Notes ...
Page 78: ...6 8 Electromagnetic Interference Notes ...
Page 94: ...Glossary 4 UL Underwriters Laboratories ...
Page 100: ...Index 6 ...
Page 101: ......