Huntleigh AlphaBed, Service Manual

Page: 15 / 94

The power failure alarm is initiated by the removal of the mains/power supply from the unit for a
period of more than 5 seconds, by a means other than operation of the ‘Run/Standby’ switch. A drop
in the supply voltage below the minimum supply specification will be interpreted as a supply failure. If
power is restored within 5 seconds, no alarm is given and normal operation is resumed.
A battery backup supply provides power to operate the visual and audible alarm.
Battery Management (Electronic Units Only)
On switching the pump to ‘Run’, the processor automatically initiates a standard charge sequence
(3 mA) for a predetermined period. On completion of the standard charge period, a trickle charge
(0.9 mA) will be applied to the battery for the remainder of the operating period.
When discharging during a power failure alarm, the battery supply will be shut down in a controlled
manner if the terminal voltage falls below 4.6 V before the alarm duration has expired.
Issue 2 Chap 1
Nov 2001 SER0004 Page 7
Mini Pump Service Manual Introduction