Power Supply
The BLE100 power supply 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 Vrms 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 power supply.
Figure 2-6
BLE100 power supply
The power supply also contains a two-position LO/HI selector that sets the start-up voltage for 38 VAC or 55 VAC. The BLE100 is shipped with the selector in the LO position which is the standard configuration. The selector should be switched to the HI position only for a 90 VAC 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 LO setting. However, changing the selector ensures that the DC supply does 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.
You must remove the power supply cover to access the selector illustrated in Figure 2-6. Section 3, “Amplifier Setup” explains changing the setting of this selector to meet system requirements.
The power supply includes a 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.
The factory-installed 20-ampere fuse, illustrated in Figure 2-8, provides power-passing to additional line extenders.
BLE100 Installation and Operation Manual
