Products
The LB-5 Load Box helps to prevent the damaging effects of ferroresonance found on lightly or unloaded 3-phase power systems. This situation typically occurs on medium voltage distribution transformers and power cables during single phase switching. As the electric power industry moves towards more efficient transformer design, this condition is becoming more common. If such conditions exist, overvoltage can lead to the breakdown of insulation resulting in damage to the transformer, lightning arresters and other equipment. When using the LB-5 to connect and apply a resistive load on the transformer secondaries, damage to distribution equipment due to ferroresonance can be prevented.
Load Box model LB-5-1 includes an additional switch to disconnect the center of this Y connected load from the ground lead. This is required for corner grounded delta transformer connections.
Load Box Features
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Helps prevent ferroresonance during single phase switching
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Portable, one person design
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Dual voltage, auto voltage selection
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Powered by transformer secondaries 120/277VAC
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5,000 watt per phase loading
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Resistive load up to 3 phases
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40A fused disconnect switch
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Blown fuse indicator lamp
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Auto-ranging voltage input - no switching required
HD Electric LB-5-1双电压负载箱（120/208V）和（277/480V）
LB-5 负载箱有助于防止在轻载或空载三相电力系统上发现的铁磁谐振造成的破坏性影响。这种情况通常发生在单相切换期间的中压配电变压器和电力电缆上。随着电力行业转向更高效的变压器设计，这种情况变得越来越普遍。如果存在这种情况，过电压会导致绝缘击穿，从而损坏变压器、避雷器和其他设备。使用 LB-5 连接变压器次级并在其上施加电阻负载时，可以防止由于铁磁谐振而损坏配电设备。
LB-5-1 型负载箱包括一个额外的开关，用于将 Y 型连接负载的中心与接地线断开。这是角接地三角形变压器连接所必需的。
负载箱特点
有助于防止单相开关期间的铁磁谐振
便携，一人设计
双电压，自动电压选择
由变压器次级 120/277VAC 供电
每相负载 5,000 瓦
高达 3 相的电阻负载
40A 保险丝隔离开关
熔断器指示灯
自动量程电压输入 - 无需切换
