Alpha Technologies BPT Series Bypass Transformer - Manual (Page 7)

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 sup-
plies 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 switch-
ing. 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. Op-
eration 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
Model Number Identification
Maximum Current Rating
1 - 40 Amps
2 - 80 Amps
3 * - 125 Amps
Type of Switch
M - Make Before Break
B - Break Before Make
Number of poles
B P S 2M3P
Bypass Transformer
VA rating
B P T 3 0 0 0 - S
Provides only 208V Input and
240V Output. The S models
cannot be used for 208V Output,
but delivery may be available on
short notice.
* 3=100 Amps if the bypass
switch SP96-033-63 is used.
Introduction
Doc# 020-133-B0 Rev. 01 / 07
3