Rockwell Automation Allen-Bradley 140U, Руководство по установке

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2
40752-195 (1)
Effective 2/2011
Molded Case Switches : The Molded Case Switch
(MCS)
is
similiar to the Circuit Breaker except that it has a differ-
trip at 15,000 Ampere but there is no overload short delay
or ground fault trip. As a result sections 2.6, 4.5, 6.8 and
7 are not applicable. In the remaining sections the term
circuit breaker shall also include the molded case switch.
Overload Trip: In accordance with standards require-
ments, the trip unit initiates a trip of the circuit breaker
within two hours of an overload of 135 percent, and a trip in
less time for higher overloads.
A “Thermal Memory” effect prevents the breaker from being
reenergized immediately after an overload. A “cooling off”
period of up to 5 minutes is required, which allows time for
the cabling to cool off.
Short delay/Instantaneous Trip : For short circuit con-
ditions that exceed the short delay pick-up settings, the
trip units initiate a trip after a delay prescribed by the I²t
response time delay action is provided by trip unts desig-
nated LSI and LSIG unless the instantaneous (I) setting is
selected.
Table 1.1: Trip Unit Types
Trip Unit Functions Digitrip RMS 310+ Trip Unit
LS LSI LSG LSIG MCS
Long Time Adjustable Ampere Rating
with Adjustable Long Delay • • • •
Short Time Adjustable Short Time Pick-up • •
with Short Time Delay l²t Ramp
Adjustable Short Time Delay

• •
with Adjustable short Time Pick-up
Instantaneous Fixed Instantaneous (Override)

• • • • •
Ground Fault Adjustable Ground Fault Pick-up
•
•
Adjustable Ground Fault Time
• ③ •

Using Trip unit with adjustable delay (LSI, LSIG), instantaneous pick-up is achieved when the lowest
time delay setting (l) is selected for non-IMM trip units.

Override setting fixed at frame withstand rating.
③
I
2
t response.