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3 Electric parts
3.1 The drive unit
The drive unit consists of a double drive with two separate drive units for the electrically
movable adjustment of the backrest and leg rest. The level adjustment of the lifting frame
is adjusted via one or two individual drives (depending on the model). The level adjust-
ment drive is connected to the control box via a helical cable. In the plug-in power supply,
the input voltage is converted into a protective low voltage of maximum 35 VDC direct
current. The motors and the hand control function with this non-hazardous low voltage.
The cables are double-insulated and the mains plug has a primary fuse.
The internal emergency lowering is carried out via a 9
V block battery. Furthermore, power adjustment al-
lows for constant speed of the functions. Therefore,
the safety functions comply with protection class II
and the moisture barrier protection type IPX4.
The maximum duty cycle is specified on the (type
plate) of the bed. For example, 10% duty cycle (2 min.
ON / 18 min. OFF) means that any electronic adjust-
ment can be performed for a max. of 2 minutes within
a timeframe of 20 minutes (protection against over-
heating).
If the maximum setting time of two minutes is exceeded e.g. by someone continuously
playing with the hand control which could lead to an overheating of the servomotors, the
thermal fuse immediately shuts off the power supply to the bed. After a cooling down
time of approx. one hour, the power will be automatically supplied again.
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