SoundCraft CPS275, CPS250 technical manual Introduction, SHORT-CIRCUIT Protection

Introduction

WARNING: THIS APPARATUS MUST BE EARTHED

The CPS250/CPS275 are linear power supplies which, like other linear supplies, produce DC voltages by rectifying, smoothing and regulating AC voltages from the secondary windings of a mains transformer. Soundcraft mixing consoles employ a number of dc voltage supply levels in their operation and these are all provided at the output of each supply unit.

The CPS275 provides higher currents than the CPS250. The CPS275 also has the capability of being linked to a second CPS275 to provide automatic power backup in the event of one of the units failing.

In regulating these voltages there is considerable heat generated, the dissipation of which is achieved through a substantial internal heat sink. A fan is incorporated which draws air over the heatsinks to provide adequate heat dissipation for the regulators and reduce the outer case temperature.

The CPS250/CPS275 is designed for installation in a 19" rack unit, occupying 2U of rack height. Refer to the section "RECOMMENDATIONS FOR INSTALLATION" on Page 5.

LED indication is provided on the front panel to show operation of the regulating circuits.

SHORT-CIRCUIT PROTECTION

The +/-17V rails can withstand a short to ground or each other for up to one second; if the short circuit remains for longer than one second then both of the 17V rails will be shut down. To reset them the supply must be switched off for 6 seconds and then switched on again.

The +5V and +48V are current limited and will self recover when any short circuit is removed.

2 Introduction