Connecting The Load; Parallel And Series Operation; Activating The Outputs - Hameg HM7044 Manual De Instrucciones

Connecting the load

The load has to be connected to the two safety terminals
For the connection please use 4 mm banana plugs.
Please note the polarity of the load terminals: the
red terminal is the positive, the blue terminal is
the negative connector.
STOP
The black terminals are the SENSE inputs. With these two
SENSE terminals the voltage loss across the cables can be
compensated. The HM7044 balances this voltage loss auto-
matically and the load will see the voltage set. Connect two
separate measurement cables in parallel to the connecting
cables of the load.
Compensation of the voltage drop across the cables
Power source
+ Source
Sense error
amplifier
source
variable
– Source

Parallel and series operation

It is mandatory that the power supplies used are defi nitely
specifi ed for these operating modes. This is the case with all
HAMEG supplies. As a rule, the output voltages to be combined
are independent of each other, hence, it is allowed to connect
the outputs of one supply with those of another or more.
Series operation
In this mode the output voltages add, the output current is
the same for all supplies. As the sum of all voltages may well
surpass the 42 V limit touching of live parts may be fatal! Only
qualifi ed and well instructed personnel is allowed to operate
such installations.
The current limit of the outputs in series should be adjusted
to the same value. If one output reaches the current limit the
total voltage will break down.
cable
+ Sense Pick-Up
load
cable
– Sense Pick-Up
A c t i v a t i n g t h e o u t p u t s
Parallel operation
.
In order to increase the total available current the outputs of
supplies can be paralleled. The output voltages of the supplies
involved are adjusted as accurately as possible to the same
value. In this mode it is possible that one or more supplies
enter the current limit mode. The output voltage remains in
regulation as long as still at least one supply is in the voltage
control mode. It is recommended but not absolutely necessary
to fi ne adjust the voltages such that the individual current
contributions remain nearly equal. Of course, the maximum
available output current is the sum of the individual supplies'
maximum currents.
Example:
A load requires 12 V at 3.7 A. Each output of the HM7044 can
deliver 3 A. First set two channels to 12 V. The sum of the cur-
rent limit of these two channels has to be at least 3.7 A. Then
connect both blue and both red safety connectors respectively
in parallel. The load has to be connected to the HM7044. With
the pushbutton OUTPUT
mally one output will limit the current at 3 A while the other
will contribute the difference of 0.7 A.
In case you should parallel power supplies of
other manufacturers with HAMEG supplies make
sure all are specifi ed for this mode of operation. If
one supply of those connected in parallel should
STOP
have insuffi cient overload protection it may be de-
stroyed. HAMEG supplies are specifi ed for series
and parallel operation.

Activating the outputs

Before the output voltages can be activated, the desired chan-
nels have to be enabled. If the selection mode of the HM7044
is not activated, the desired channels can be enabled by ope-
rating the buttons I, II, III or IV
glow. Only the enabled channels are put on by pushing the
OUTPUT button . The OUTPUT-LED
the enabled channels glow. Even during the outputs are on, the
channels can be enabled and disabled using the CH.-buttons
I, II, III and IV . Operating the OUTPUT-button
outputs are turned off. The OUTPUT-LED
the voltage will be turned on. Nor-
. The respective CH.-LEDs
and the CH.-LEDs of
again, all
is off.
Subject to change without notice
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