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HOSE AS 3905021 - Caterpillar

3905021 HOSE AS Caterpillar parts HOSE
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Caterpillar 3905021 HOSE AS

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Bypass AC Source
Use the following information to determine the required rating of the protective circuit breaker on bypass AC input.Note: If the installation includes a transformer on the bypass AC input, allow for the inrush current caused by magnetization of the transformer windings.
Table 3
Electrical Parameters for Bypass AC Source (480 V)    
Rated UPS output in kVA     Current bypass AC source (4)    
Rated current (In) for unit Rate current for 25% overload     for 50% overload    
150     180     236     270    
180     217     283     325    
225     271     320     407    
( 4 ) The bypass AC source currents have been determined for a rated phase-to-phase voltage of 480 V. The load power factor is 0.9. The bypass AC source currents have been determined for full rated load as well as overloads of 25% or 50%. When choosing the circuit breaker rating, use the "rated current" column. Check that the circuit breaker tripping curves are compatible with the data in the overload columns.
Table 4
Maximum Permissible Current    
UPS output in kVA     Current/Time    
150     33 (In) for 20 ms    
180     27 (In) for 20 ms    
225     22 (In) for 20 ms    
Illustration 1 g02383657
Fuse Usage ChartCircuit Breaker for Line Side of UPS
The following information is provided for a single UPS unit. Note: Ensure that short-circuit current and protection of the static switch semiconductors on the bypass AC input is considered.
Table 5
Recommended Ratings for Circuit Breakers for the Line Side of UPS    
Rated UPS output in kVA     CB on normal AC input     CB on bypass AC input    
circuit breaker control unit     circuit breaker     control unit    
150     250A     200A     250A     200A    
180     250A     250A     250A     250A    
225     400A     400A     400A     400A    Circuit Breaker for Load Side of UPS
The load side breakers provide protection for each UPS output circuit.Note: If the recommended breaker is not installed and a short-circuit occurs, a break longer than 20 minutes on the remaining output circuits may occur.
Table 6
Recommended Breaker Ratings for the Load Side of a Single UPS    
Rated UPS output in kVA     Load side circuit breaker    
Circuit Breaker Control Unit    
100kVA to 225kVA     100A     63A curve C 100A curve B    Parallel Connected UPS Units
For installations with redundant units, only the units required to supply the load power must be considered. An example is an installation that consists of three UPS units in parallel. One UPS unit is redundant and two UPS units are used to determine bypass AC source, load currents, and cable cross-sections. Table 7 provides an example for rating of up to four UPS units in parallel.
Table 7
Parameters for Bypass AC Source and Load Cables for a UPS Units in Parallel    
Rated unit output in kVA     Number of parallel connected     Total

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