参数资料
| 型号： | C1938 |
| 厂商： | Cooper Bussmann |
| 文件页数： | 20/40页 |
| 文件大小： | 0K |
| 描述： | JUNCTION BLOCK STUD BLK BASE |
| 标准包装： | 50 |
| 端接块类型： | 接线盒区块 |
| 电路数： | 1 |
| 导线入口数目： | 1 |
| 行数： | 1 |
| 电流： | 250A |
| 顶部端子： | 接线柱 |
| 底部端子： | 接线柱 |
| 阻挡层类型： | 开路 |
| 特点： | 3/8 接线柱 |
| 颜色： | 黑 |
| 包装： | 散装 |
| 安装类型： | 底座安装或面板安装 |
| 材料 - 绝缘体： | 热塑塑胶 |
| 其它名称： | 283-3908 C1938-ND |
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Basic Overcurrent Technology
Overcurrent devices may serve several purposes in
electrical circuits:
? To protect components, equipment, and associated wiring
from the effects of electric circuit overloads and/or short
circuits.
? To isolate branch circuits from the main power supply
once an overload or short circuit has occurred.
Fuses and circuit breakers are commonly selected as the
preferred overcurrent device.
TYPES OF OVERCURRENT
An overcurrent device is constructed to react in a
prescribed fashion to varying levels of electrical current,
where at pre-determined levels, the device provides
interruption of the current flow through it. Any current that
exceeds the ampere rating of the fuse or circuit breaker is
an overcurrent. Overcurrents are generally classified as
either short circuits or overloads and are defined as
follows:
? Short circuit - a current that greatly exceeds the rating of
the device. It is caused when a malfunction or accident
creates a break in the normal path allowing electricity to
flow directly to ground or another phase. This shorter
current path bypasses the resistance offered by the
circuit components and the load connected in the normal
current path. In this situation there is little resistance to
impede the current and the current will build to a level
where the heat generated can cause insulation damage
and/or equipment breakdown.
? Overload - an overcurrent that is within the normal
current path. Overloads occur when the current exceeds
the value for which the equipment or associated wiring is
rated. This typically occurs when too many devices are
connected to the circuit or when a device connected to
the circuit malfunctions. Overloads are also caused by
harmless temporary surge currents; such as when motors
are started. These overload currents are normal, usually
brief in duration, and have no harmful effect on the circuit
components. (It is important that protective devices do
not react to such overloads.) Sustained overloads,
however, may slowly cause overheating of the wiring and
the components. Provided the overload is of sufficient
magnitude and duration to activate the device, the circuit
protection device shall open before the overload induces
system component failures.
SELECTING OVERCURRENT PROTECTION
During normal conditions, an overcurrent protection device
must carry the current without nuisance openings.
However, when an overload or short circuit occurs the
device interrupts the overcurrent and withstands the
voltage across the device. To properly select an
overcurrent device the following items must be carefully
considered:
? Voltage rating - represents the maximum system voltage
present in the circuit in which the overcurrent device is
installed. The system voltage should not exceed this
value for proper operation of the device during an
overcurrent event.
? Current Rating - the amperage value marked on the
circuit protection device. The circuit protection device is
designed to handle this value under steady operating
conditions and at room ambient temperatures. Since field
applications often deliver loading conditions and ambient
temperatures that vary from ideal nominal settings, it is
recommended that circuit designers select device ratings
above the nominal circuit current continuous load to
prevent nuisance trips. Additionally, the continuous
current flowing through the overcurrent protective device
should not be more than 80% of the current rating.
? Characteristics of equipment to be protected - during
the operation of protected equipment, system current can
significantly vary. This is particularly evident when motor
or other inductive loads in the circuit cause large current
surges during start-up. Circuit protection designers should
be aware of these surges and/or in-rush characteristics
and select the overcurrent protection devices accordingly.
? Available short circuit current - during a fault or short
circuit condition the fuse or circuit breaker may see a
large amount of current. Large DC battery supplies and
high current rated electric distribution buses often have
this potential for severe short circuits. In these situations,
the circuit protection device should have an interrupting
rating that is equal to or greater than the short circuit
current that can be delivered.
? Ambient temperature - the time it takes to interrupt the
current is dependent upon the ambient current
temperature characteristics. Ambient temperature refers
to the temperature of the air immediately surrounding the
circuit protection device. The ambient temperature around
the fuse or circuit breaker can be appreciably different
than the outside room or larger enclosure containing the
device. This can occur when the device is contained in a
tight area or it is mounted in or near a heat-producing
component such as a transformer or resistor. When
selecting a fuse or circuit breaker at ambient
temperatures significantly different from the stated
nominal temperature, the circuit designer should adjust
the selected overcurrent protection rating based on the
published temperature re-rating curves.
OVERCURRENT PROTECTION DEVICES
Two categories of overcurrent devices are available.
Fuses
The key component of a fuse is the “element’, a short
piece of metallic wire or link made of a material with a
18
Cooper Bussmann Transportation Products ? Phone: 1-888-867-8194 ? Website: http://www.coopertp.com
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| C1938-1 | 功能描述:熔丝座 BLACK 5/16"STUD JB TIN PLATE RoHS:否 制造商:Littelfuse 产品: 电流额定值:30 A 电压额定值:1000 VDC 极数:1 系列: 安装风格:DIN Rail 端接类型: 轴类型: 工作温度范围: |
| C1938-1R | 功能描述:熔丝座 RED 5/16"STUD JB TIN PLATE RoHS:否 制造商:Littelfuse 产品: 电流额定值:30 A 电压额定值:1000 VDC 极数:1 系列: 安装风格:DIN Rail 端接类型: 轴类型: 工作温度范围: |
| C1938R | 功能描述:熔丝座 RED 3/8"STUD JB ZINC PLAT RoHS:否 制造商:Littelfuse 产品: 电流额定值:30 A 电压额定值:1000 VDC 极数:1 系列: 安装风格:DIN Rail 端接类型: 轴类型: 工作温度范围: |
| C194 | 制造商:Datak Corporation 功能描述:Cable Assembly RS-232 3.048m 28AWG 25 POS D-Sub to 25 POS D-Sub M-F |
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