3.2.10Maintenance Bypass

Maintenance Bypass switchgear (cabinet, panelboard, switchboard or custom switchgear) allows you to totally isolate the UPS system from all power sources, while you maintain power to the critical load.

Your installation may have a two-breaker, three-breaker, or four-breaker Maintenance Bypass, or none at all. The main differences are the locations of the Rectifier Input Breaker and the Bypass Input Breaker (BIB).

Another option that may be present at your site is an alternate power source (generator) and an automatic transfer switch (ATS).

Note that to totally isolate the UPS system from all power sources, the Main Input switchgear and battery circuit breakers must also be opened.

CAUTION

Instructions for operating the Maintenance Bypass circuit breakers are on the Maintenance Bypass cabinet. Make sure you understand the proper sequence before operating any circuit breaker. Operating a Maintenance Bypass circuit breaker out of sequence could cut off power to the critical load.

Figure 57 Load on Maintenance Bypass (Two Breakers)

 

 

 

 

RIB

 

 

 

 

RIB

 

 

 

RIB

 

 

 

 

BIB

BFB

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

UPS #3

UPS #2

UPS

#1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CB1

 

 

CB1

 

 

CB1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

SBS

 

 

 

 

 

 

 

 

 

 

 

 

 

R

 

 

R

 

 

R

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

SBB

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

MBB

 

 

I

 

 

I

 

 

I

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

System

 

 

 

 

 

 

 

 

 

 

CB2

 

 

 

CB2

 

 

 

CB2

 

 

 

 

 

 

SKRU

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Controls

 

 

 

 

 

 

 

 

 

 

Output MIB

 

 

 

 

 

 

 

 

 

SCCT

 

 

 

 

 

 

 

 

 

To Critical Load

 

 

 

 

 

 

 

 

 

 

 

MBD

 

 

MBD

 

 

 

MBD

 

 

 

 

 

 

 

 

 

SCCT

Battery

Battery

Battery

(can accommodate up to 6 UPS modules)

 

 

 

 

 

 

 

 

 

88

Operation

DISCONTINUED

 

 

PRODUCT

Page 94
Image 94
Liebert Series 600T manual Load on Maintenance Bypass Two Breakers