Advanced Applications; Compensating For Voltage Drops On The Supply Lines (Sense Mode); Parallel And Serial Mode - Hameg HMP Series User Manual

7 Advanced Appli-
cations
7 . 1 Compensating for Voltage Drops on the Supply
Lines (Sense Mode)
Fig. 7.1: Compensating the voltage drops in diagram
The two SENSE lines allow you to compensate voltage
drops on the supply lines to the load so that the actual
selected voltage is applied to the load. Use two separate
measuring lines to connect the load to the two external
black safety sockets of the respective channel (see figure
above).
7 .2

Parallel and Serial Mode

It is assumed that only qualified and trained personnel service
the power supplies and the connected consumers.
To increase output voltage and currents, it is possible to
operate the channels in serial or parallel mode. These op-
erating modes require that power supplies are suitable for
the parallel and/or serial mode. This is the case for HAMEG
power supplies. In general, the output voltages to be com-
bined are independent. The outputs for one or multiple
power supplies can be interconnected for this purpose.
7 .2 . 1 Serial Mode
If the maximum total instrument power is exceeded, the output
(OUTPUT) will automatically be switched off! A warning will be
shown on the display.
As can be seen, this type of interconnection adds the indi-
vidual output voltages. The same current flows through all
outputs. The current limits for the outputs wired in series
should be set to the identical value. If one of the outputs
exceeds the current limit, the total voltage will naturally
collapse.
It is advisable to set both voltages to a similar value to
distribute the loads evenly (not absolutely necessary). If a
(low resistance) load is connected, it is essential to activate
more than one channel. This could damage the instrument
32 V
2.5 A
CH1
Fig. 7.2: Example serial mode
(especially protective diodes). Therefore, it is necessary to
always have both channels or no channel at all switched
on.
7 .2 .2 Parallel Mode
If it is necessary to increase the total current, the power
supply outputs must be wired in parallel. The output volt-
ages for the individual outputs should be set to the same
voltage value as precisely as possible. For slight voltage
differences, it is common in this operating mode to first
charge a voltage output up to the current limit; the other
For the parallel mode, you must ensure that the allowed protec-
tive low voltage can be exceeded.
voltage output provides the remaining current. The maxi-
mum total current is the sum of the individual currents of
all sources connected in parallel. For power supplies that
are connected in parallel, It is possible that compensating
currents flow within the power supplies. The use of power
supplies by other manufacturers, which are potentially not
overload proof, can cause destruction of these units as
currents may be distributed unevenly.
32 V
2.5 A
CH1
32 V
5 A
Fig. 7.3: Example parallel mode
Generally, a higher current will first be supplied from the
channel with the higher output voltage. Once this channel
reaches its power limit, the remaining current will be made
available by the channel that is connected in parallel. In
this scenario, it is unpredictable which channel will supply
the higher current because it is also possible for channels
with identical voltage values to display a low voltage
difference.
By increasing the voltage slightly, the load distribution can be
manipulated. If the voltage for a channel is to be increased by
50mV, for instance (by a set of identical cables), the current will
initially be provided by this channel.

Advanced Applications

32 V
2.5 A
CH2 CH3
64 V
2.5 A
32 V
2.5 A
CH2 CH3
39