Operating instructions

Overview 2-7
Figure 2-7 illustrates the MPPS-II installed in the lid of the MBV3-100*.
Figure 2-7
MPPS-II power pack
The MPPS-II also contains a two position
LO/HI selector that sets the start-up voltage for 38 VAC
or 55 VAC. The MBV3-100* 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. If
you ordered a model with the 90VAC option (Figure 2-2), the jumper is set to the
HI position at
the factory. This jumper position sets the start-up voltage at 55 VAC. Because this is only 5 V
below 60 VAC, it is not practical to switch to
HI 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.
MBV3-100* Installation and Operation Manual