molded case circuit breakers - Eaton Canada
molded case circuit breakers - Eaton Canada
molded case circuit breakers - Eaton Canada
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276<br />
SWITCHGEAR (MEDIUM VOLTAGE)<br />
DH Switchgear Assemblies,<br />
Power Circuit Breakers, and Renewal Parts<br />
PRODUCT DESCRIPTION<br />
Westinghouse DH Draw-out Air Magnetic<br />
Power Circuit Breaker (Interphase Barrier<br />
Removed)<br />
REPLACEMENT CAPABILITIES<br />
50DH250E 1200 Ampere DH-VR Breaker<br />
Low Resolution Photo<br />
Westinghouse DH medium voltage<br />
metal-clad switchgear with type DH<br />
“De-Ion” air <strong>circuit</strong> <strong>breakers</strong> was introduced<br />
in 1939. The draw-out breaker<br />
element consists of an operating mechanism<br />
that drives a set of three pole units.<br />
When the breaker is tripped, the moving<br />
and stationary contacts separate. The<br />
resulting arc on each phase is drawn up<br />
and into the arc chutes which dissipate the<br />
arc through ceramic splitter plates. The<br />
de-ionizing interruption process is aided<br />
magnetically by the arc chute blow out<br />
coil assembly.<br />
DH switchgear was available in indoor and<br />
in sheltered aisle and aisle-less outdoor<br />
enclosures. DH metal-clad switchgear<br />
structure dimensions were standardized,<br />
but varied with individual breaker ratings.<br />
Widths varied from 20 inches for the<br />
50DH75 (1200 ampere) light duty rating to<br />
26 inches for the 50DH250 (1200 ampere)<br />
rating to 36 inches for most 2000 ampere<br />
and 7.5 and 15kV ratings.<br />
New DH factory manufactured switchgear<br />
structures and <strong>breakers</strong> are no longer<br />
available. However, Cutler-Hammer offers<br />
the following through qualified retrofitting<br />
organizations.<br />
DH-VR Vacuum Replacement Breakers<br />
The DH-VR is a brand new direct roll-in<br />
replacement vacuum breaker for DH air<br />
magnetic <strong>breakers</strong>. The DH-VR breaker<br />
permits DH switchgear modernization<br />
by using state-of-the-art Cutler-Hammer<br />
VCP-W vacuum breaker technology. The<br />
DH-VR is factory designed and manufactured<br />
with complete factory and ANSI<br />
design testing.<br />
Ratings<br />
DH switchgear ratings started with the<br />
light duty 50DH75 (5 kV, 75 MVA) 1200<br />
ampere breaker. The spectrum of ratings<br />
also included 7.5 and 15kV ratings. The<br />
maximum breaker rating produced was<br />
the 150DH1000 (15kV, 1000 MVA) 3000<br />
ampere.<br />
Chronology<br />
DH switchgear was introduced in 1939<br />
and was actively manufactured by<br />
Westinghouse in complete switchgear<br />
assemblies until the introduction of DHP<br />
switchgear in 1963. As production activity<br />
tapered after 1963, only match and lineup<br />
additions to existing DH switchgear were<br />
manufactured along with complete<br />
replacement <strong>circuit</strong> <strong>breakers</strong> and renewal<br />
parts. The last new manufactured DH<br />
<strong>breakers</strong> and switchgear cells were<br />
produced in 1983.<br />
Renewal Parts<br />
Cutler-Hammer no longer offers new manufactured<br />
renewal parts for DH switchgear<br />
structures and <strong>breakers</strong>. Contact Homewood<br />
Products at 412-665-2718.<br />
March 2001
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