Operator`s manual

Make-Before-Break
Make-Before-Break Bypass Switches provide continuous power to the load during
switching. The bypass supply and the UPS output supply are momentarily connected in
parallel to ensure that power to the load is not interrupted when switching. The duration of
time the two supplies remain in parallel is determined by how quickly the switch is
operated. The switch should always be operated in a quick continuous motion to ensure
reliable operation of the switch and continuous undisturbed power to the load.
Break-Before-Make
Break-Before-Make Bypass Switches ensures a break in power to the loads during
switching. The bypass supply and the UPS output supply are never connected in parallel
during the switching process. This ensures there is a break in supply voltage to the
output side of the switch. The duration of the break is determined by how quickly the
switch is operated. Operation of the switch should be quick and decisive to ensure safe
and reliable operation of the switch while minimizing the duration of the break to the load.
The break-before-make type of Bypass Switch ensures for safe operation, especially if the
UPS output voltage and the Bypass supply are out of phase.
CAUTION: Please consult Table 1 Bypass Switch Selection Guide and the schematic
diagrams at the end of the manual for selecting the proper type of Bypass Switch for your
application. The model type number designation is derived according to the definition
below.
Bypass Switch
1.3 Bypass Switch Terminology,
continued
1. INTRODUCTION
2
Model Number Identification
Figure 9.
System Bypass Schematic
240V IN - 120V OUT
19
5. SCHEMATIC DIAGRAMS
Maximum Current Rating
1 - 40 Amps
2 - 80 Amps
Type of Switch
M - Make Before Break
B - Break Before Make
Number of poles
B P S 2M 3 P
Bypass Transformer
VA rating
B P T 3000 - S
Provides only 208V Input and
240V Output. The S models
cannot be used for 208V Out-
put, but delivery may be avail-
able on short notice.