Maintenance bypass schematics

Introduction

There are several types of bypasses available from Advance

Manual simple maintenance switch
Automatic reverts to mains if UPS fails
Dual redundant for selecting between two in-phase supplies
Dual redundant used in `one fault tolerant' mode for mission crucial applications
HotSwitch for selecting between two out-of-phase supplies
Each logical schematic is shown in the `normal' mode
manual automatic
s1a and s1b are ganged wipers on a manual switch the switch is MBB (make before break) in bypass mode the UPS may be safely removed from the circuit s1 is the same as the manual version the relay control detects the output voltage from the UPS. If the UPS output fails the Relay Control operates the two switches which connect the critical load to the mains and the neon lights

Switches for more critical applications

dual redundant (DRS) hot switch
the schematic is per DRS but one supply has some added power conditioning the HotSwitch permits the use of supplies which are NOT snychronised
power is supplied from two independant sources which MUST be in-phase if supply `b' fails the control changes the critical load to supply `a' the keyswitch provides manual changeover both variations exhibit a small changeover break which will not affect ICT systems

For more details see FBS series and special needs version or bypass considerations