User Manual

Page 71
EA Elektro-Automatik GmbH
Helmholtzstr. 31-33 • 41747 Viersen
Germany
Fon: +49 2162 / 3785-0
Fax: +49 2162 / 16230
www.elektroautomatik.de
[e-mail]
ELR 9000 Series
Share-
Bus
E.U.T
E-LOAD 1 PSU 1
PSU nE-LOAD n
Master-Slave
Master-Slave
Conguration C:
Multiple e-loads and Multiple power supplies, plus 1 test
object (E.U.T), for raising the total performance.
The load combination and the power supply combination
create in each case a total system with a dened power. It is
necessary also here to match the nominal values of the two
systems. i.e an 80V DC input of the loads to a max. 80V DC
output of the power supplies.
3.9.3.3 Application example:
Charging and discharging a battery, 24V/400Ah, using the wiring example in conguration A.
• Power supply PS 9080-170 3U set to: Umax = 28.5V, Imax = 50A, Pmax = 5000W
• Electronic load ELR 9080-170 set to: Imax = 100A, Pmax = 3500W, U = variable (controlled)
• Assumption: battery has a voltage of 26V at test start
1. Discharge of the battery to 24V ---> voltage on the load set to 24V, load and power supply activated
Reaction: the e-load will load the battery with a maximum of 100A in order to discharge it to 24V. The power supply
will, in this case, deliver no current as the load will set the voltage of the power supply to that of the battery using
the Share Bus. The load will gradually reduce the current in order to maintain the voltage at 24V. Once the battery
voltage has reached 24V with a discharge current of 0A, the voltage will be maintained at this level by charging
from the power supply.
2. Charging the battery to 27V ---> voltage on the load set to 27V.
Reaction: the power supply will charge the battery with a maximum 50A. The current will gradually reduce with
increasing voltage as a reaction to the changing internal resistance of the battery. The load absorbs no current.
On reaching 27V the power supply will deliver only the current needed to maintain battery voltage.
3. Set voltage on the load to 40V
Reaction: the power supply will charge the battery up to max. 28.5V, as this is so dened in the settings for the supply.
Thus it is apparent that it is important to know the maximum permissible parameters for the application and to set
the devices accordingly so as not to damage the application.