15
Instrument
transformers
Current transformers (CTs)
Figure 5: Type SDV7-AR distribution circuit
breaker with interphase barriers and bushing
current transformers installed in primary
compartment on page 16 illustrates bushing
(toroidal) CTs installed in the primary
compartment of a type SDV7-AR distribution
circuit breaker. The roof bushings pass
through the CTs. Up to two CTs may be
mounted around each roof bushing. The
bushing CT connections are wired to separate
terminal blocks located in the low-voltage
operator compartment.
Hazardous voltages.
Will cause death, serious injury or property damage.
Do not operate current transformers with the secondary open circuited.
Current transformers must be either connected to a load or short circuited.
Current transformer secondary circuits also must be grounded.
Phase barriers
Phase barriers are provided on all 27.6 kV and
38 kV class type SDV7-AR distribution circuit
breakers as shown in Type SDV7-AR
distribution circuit breaker with interphase
barriers and bushing current transformers
installed in primary compartment on page
16. These plates of insulating material are
attached to the circuit breaker housing and
provide suitable electrical insulation between
the vacuum interrupter primary circuits.
Summary of Contents for SDV7-AR
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