Document title

Recommended AC Input breaker Flatpack 2 xx/2000

Prepared by

Frode Nordby Approved by

Kunt Ramnæs Date (dd.mm.yyyy)

18.03.2008 Revision

3 Document no. 2020432

Page

1 of 4

Print date: 19 Mar 2009 Page 1 of 4 Issue: 3 Date: 2008-10-21

Introduction: Internally in each rectifier module there are two input fuses. Main purpose for these is to limit short circuit currents and disconnect the module from input AC if failure occurs inside the module. Two different power shelves (PS) for 4 rectifiers exist: PS 4AC – for separate AC feeding to each rectifier position. This PS is used as default in the CTO configuration. PS 2AC – for two AC inputs where one input feeds rectifier positions 1 & 2 and one AC input feeds rectifier 3 & 4. PS 2AC is used as default in the CTE configuration (large systems – min. 24kW), and basically not suitable if only one PS is present and 3-phase AC feeding is required. Depending of chosen system configuration, the power supply system can be pre-wired for different AC input feedings from upstream AC switch board:

1. Separate single phase AC feeding to each individual rectifier module (4AC PS only) 2. Single phase AC feeding several modules 3. 3-phase AC feeding several modules, IT network, (3-phase, 4 wire delta network) 4. 3-phase AC feeding several modules, TN network (3-phase, 5 wire, star)

When dimensioning the upstream feeding mains breaker, one or several of the following parameters have to be met:

A. Discrimination between module input fuse and upstream feeding AC breaker B. Full load with a fully populated system at nominal voltage (i.e. @ 230V AC) C. Full load with a fully populated system at normally lowest nominal voltage from local distributor (i.e. @ 205V

AC) D. Full load with a fully populated system at lowest input voltage specification for the rectifiers (i.e. @ 185V

AC) Obviously A have to be fulfilled, (unless individual feeding of each rectifier module). As a minimum B have to be fulfilled but having in mind that distributors normally can guarantee nominal AC voltage +/-10% comply to B is recommended. If the power system is installed in an area with weak mains and there is a chance of variation below -10%, comply according to D should be considered. Below you will find Eltek’s recommendation for upstream AC feeding breaker which is based up on number of rectifier modules connected to each phase and worst case short circuit current which can occur inside the module. IMPORTANT! The installation company connecting the system to input mains do have the final responsibility to investigate local conditions when it comes to mains voltage, and the input mains short circuit capacity. This company or person has the responsibility to choose mains breaker and verify upstream discrimination and full load capability.

Input breaker recommendation NOTE! All calculations for 1-2 Power Shelves (PS) are based on that 4AC PS is present. (For connection details see “Schematic/connection drawing FP2 DC Power System” included in the user documentation)

1.1 Input: 230V AC individual single phase for each rectifier

TO OBTAIN SELECTIVITY Selectivity NOT obtained RecomMended breaker Recommended breaker Rectifier Full load

current (A) Th/Mag Hy/Mag

Full load current (A)

Th/Mag Hy/Mag 1 12,6 25A D-char. 25A C2-char 12,6 16A C-char. 16A C2-char

NOTE! Each rectifier has a separate 230VAC single phase input.

Document title

Recommended AC Input breaker Flatpack 2 xx/2000

Prepared by

Frode Nordby Approved by

Kunt Ramnæs Date (dd.mm.yyyy)

18.03.2008 Revision

3 Document no. 2020432

Page

2 of 4

Print date: 19 Mar 2009 Page 2 of 4 Issue: 3 Date: 2008-10-21

1.2 Input: 230V AC 1x single phase

185V AC 205V AC Recommended breaker per

input Recommended breaker per

input Number of

Power shelves

Full load current per

input (A) Th/Mag Hy/Mag

Full load current per

input (A) Th/Mag Hy/Mag

1 48,0 50A C-char. 50A C2-char 43,0 50A C-char. 50A C2-char NOTE! 1 separate single phase input feeding one Power Shelf with max. 4 rectifiers on each single phase input. This is an option in standard CTO for 8kW applications only.

1.3 Input: 230V AC 3x single phase

185V AC 205V AC Recommended breaker per

input Recommended breaker per

input Number of

Power shelves

Full load current per

input (A) Th/Mag Hy/Mag

Full load current per

input (A) Th/Mag Hy/Mag

1 24,0 25A D-char. 25A C2-char 21,5 25A D-char. 25A C2-char 2 36,0 40A C-char. 40A C2-char 32,2 40A C-char. 40A C2-char

NOTE! 3 separate single phase inputs are feeding up to 2 Power Shelves with max. 3 rectifiers on each single phase input. This is an option in standard CTO.

1.4 Input: 230/400V AC 3-phase, TN network (5 wire system)

185V AC 205V AC Recommended input

breaker Recommended input breaker Number of

Power shelves

Full load input

current per phase (A) Th/Mag Hy/Mag

Full load input

current (A) Th/Mag Hy/Mag

1 24,0 25A D-char. 25A C2-char 21,5 25A D-char. 25A C2-char 2 36,0 40A C-char. 40A C2-char 32,2 40A C-char. 40A C2-char 3 47,9 50A C-char. 50A C2-char 43,0 50A C-char. 50A C2-char

1.5 Input: 230V AC 3-phase, IT network (4 wire system)

185V AC 205V AC Recommended input

breaker Recommended input breaker Number of

Power shelves

Full load input

current per phase (A) Th/Mag Hy/Mag

Full load input

current (A) Th/Mag Hy/Mag

1 31,7 32A D-char. 32A C2-char 28,4 32A D-char. 32A C2-char 2 62,3 63A C-char. 63A C2-char 55,8 63A C-char. 63A C2-char 3 83,0 100A C-char. 100A C2-char 74,4 80A C-char. 80A C2-char

Document title

Recommended AC Input breaker Flatpack 2 xx/2000

Prepared by

Frode Nordby Approved by

Kunt Ramnæs Date (dd.mm.yyyy)

18.03.2008 Revision

3 Document no. 2020432

Page

3 of 4

Print date: 19 Mar 2009 Page 3 of 4 Issue: 3 Date: 2008-10-21

Rectifier module input fuse characteristic Fuse type used at the input in Flatpack 2-xx/2000 module: SB 3AB 15A Littlefuse or equivalent. Fuse characteristic:

Document title

Recommended AC Input breaker Flatpack 2 xx/2000

Prepared by

Frode Nordby Approved by

Kunt Ramnæs Date (dd.mm.yyyy)

18.03.2008 Revision

3 Document no. 2020432

Page

4 of 4

Print date: 19 Mar 2009 Page 4 of 4 Issue: 3 Date: 2008-10-21

Breaker types The above recommendation is based up on use of two alternative types of feeding breakers:

• Th/Mag Thermal magnetic circuit breaker, type Siemens 5SX or 5SY series, MG C60H series or similar. Note! This breaker technology has normally a thermal de-rating at temperatures above +30oC. See manufacturers data

• Hy/Mag Hydraulic magnetic breaker, type CBI QF frame or QY frame, Airpax, or similar (http://www.cbi.co.za/)

Main difference between the two alternatives, besides thermal de-rating, is that Th/Mag breakers has undefined tripping at very short spikes (below 10 milliseconds) and are sensitive for high and short currents. The Hy/Mag technology are mechanically slower the first few milliseconds and are able to withstand short spikes As a rule of thumb, a breaker should not have continuously load of more than 80% of rated current. In other words, input mains breaker should have a rating of “Full load input current per phase” mentioned in the table above, divided by 0,8 to take care of max load. In addition it needs to have a rating at least equal or higher than lowest recommended rating mentioned in the tables above.