Power Supplies; Standard Power Supply - Motorola BLE Series Installation And Operation Manual

P o w e r S u p p l i e s
The BLE*/* is available with a standard power supply or the optional power-factor-corrected
(PFC) power supply. The following subsections describe and illustrate the differences.

Standard Power Supply

The power supply of the BLE*/* is a separate circuit board mounted to the underside of the
amplifier module and is capable of 60 Vac or 90 Vac powering. The power supply provides a
regulated 24 Vdc output over an ac input between 38 V and 90 Vrms with a line frequency from
50 Hz through 60 Hz. Potentiometer R25 adjusts the output voltage to 24 Vdc, however, this is
set at the factory and field adjustment is not recommended.
Figure 2-6 illustrates the components on the standard power supply circuit board:
F i g u r e 2 - 6
B L E * / * s t a n d a r d p o w e r s u p p l y
P2-3
P2-2
D1
P2-1
The power supply also contains a two position
38 Vac or 55 Vac. The BLE*/* is shipped with the selector in the
standard configuration. The selector should be switched to the
system. This sets the start-up voltage at 55 Vac. Because this is only 5 V below 60 Vac, it is not
practical in a 60 Vac system. There is no damage to the amplifier if the selector is not changed
from the standard setting. However, changing the selector ensures that the dc supply does
LO
not turn on until the proper input voltage, 38 Vac or 55 Vac, is reached. This prevents excessive
loading of the system power supply during turn-on after a system shutdown.
The power supply includes a heavy-duty gas discharge tube which you can replace with the
optional fast-transfer electronic-crowbar (FTEC) surge protector. The FTEC is a crowbar circuit
that fires at approximately 245 V and presents a short circuit to the line during periods of
overvoltage. After the ac input voltage returns to normal, the FTEC resumes its open state.
C26 C2
L8
C25
P1
1
X1 X2
SURGE PROTECTOR
Surge protector
or FTEC
LO
R25
L2
C7
C6
C5
C1
C22
R25 C11 C10 J1
U4
E1
E2
U3
Q1 U2
L3
C17
LO/HI
selector
/ selector that sets the start-up voltage for
HI
position which is the
LO
position only for a 90 Vac
HI
B L E * / * I n s t a l l a t i o n a n d O p e r a t i o n M a n u a l
O v e r v i e w 2 2 2 2 - - - - 7 7 7 7
L1
C3
D5
C12
LO
HI
T1
U1