30
© 2006, Elektro-Automatik GmbH & Co. KG
Irrtümer und Änderungen vorbehalten
EN
Instruction Manual
EL 3000 A Series
Date: 12-05-2011
About the device
3.3 Scope of delivery
1 x Electronic load
1 x Printed user instruction manual
1 x Mains cord
4. General
4.1 Prologue / Warning
This user instruction manual and the device are intended
to be used by users who know about the principle of an
electronic load. The handling of the device should not
be left to persons who are unaware of the basic terms of
electrotechnology, because these are not described in
this manual. Inappropriate handling and non-observance
of the safety instructions may lead to a damage of the
device or loss of warranty!
4.2 Mains connection / Grounding
The unit is grounded with the mains cord. Thus the unit
may only be operated at a mains socket with grounding
contact. This must not be interrupted by an extension
cable without earth conductor!
4.3 Cooling
The air inlets on the front and the air outlets at the rear
have to be kept clean to ensure proper cooling. Take care
of at least 20cm distance (at the rear) to any surrounding
objects in order to guarantee unimpeded air flow.
Caution!
Hot air can emerge from the air outlets!
4.4 Disassembly
Warning!
The unit must not be opened and repaired by
the user.
When opening the unit or removing parts from the inside
with tools there is risk of electric shock by dangerous
voltages. Open the unit only at your own risk and discon-
nect it from the mains before.
Any servicing or repair may only be carried out by trai-
ned personnel, which is instructed about the hazards of
electrical current.
4.5 Temperature shutdown / Ventilation
The device is equipped with temperature controlled fans
which are permanently running. At higher temperatures,
the RPM will increase and result in a certain noise de-
velopment.
In case of overheating the device is automatically swit-
ched offline (standby). After cooling down to the allowed
temperature range it is automatically switching online
again.
The error remains indicated in the display until it is ack-
nowledged by using the „Input on/off“ button or pin REM-
SB of the analogue interface (while in remote control) or
read out via digital interface by a command. An internal
error buffer stores up to three different alarms and is
purged when read.
4.6 Dynamic characteristics and stability criteria
The electronic load is characterised by short rise and
fall times of the current, which are achieved by a high
bandwidth of the internal regulation circuit.
In case of testing sources with own regulation circuits at
the load, like for example power supplies, a regulation
instability may occur. This instability is caused if the com-
plete system (feeding source and electronic load) has too
little phase and gain margin at certain frequencies. 180°
phase shift at > 0dB amplification fulfills the condition
for an oscillation and results in instability. The same can
occur when using sources without own regulation circuit
(eg. batteries), if the connection cables are highly induc-
tive or inductive-capacitive.
The instability is not caused by a malfunction of the load,
but by the behaviour of the complete system. An impro-
vement of the phase and gain margin can solve this. In
practice, a capacity is directly connected to the DC input
of the load. Recommended is 1µF, for slower systems
some 100µF can be necessary.
The regulation circuit is physically unable to regulate the
internal resistance to 0, which also prevents maximum
input current at very low input voltage. See the illustra-
tions below for clarification. The first one depicts that at
least 1,7V input voltage is required for maximum current.
Elektronische Lasten EL3000 / EL9000
EL3000
Seite 1 von 2
Staberock
E
A
Bienert
Diagramm
Thema
Projektleiter
Bearbeiter
Projekt
EA - Elektro
Automatik
Art. Nr.
Datei : H:\dos\technik\Projekte\EL3000-9000A\Messungen & Tests\messung ue zu ie an el3000.vsd
CAD Sys. MS-Visio
Measurings EL3160-60
Current
Voltage
60A
1,35V
45A
0,97V
30A
0,63V
15A
0,32V
Measurings EL3400-25
Current
Voltage
25A
0,95V
20A
0,74V
10A
0,36V
5A
0,18V
I
in
/A
U
in
/V
20
15
10
5
0,5
1
1,5
25
Resistance regulation (U
in
/I
in
ratio)
25A load
I
in
/A
U
in
/V
60
45
30
15
1
1,5
Resistance regulation (U
in
/I
in
ratio)
60A load
0,5
Elektronische Lasten EL3000 / EL9000
EL3000
Seite 1 von 2
Staberock
E
A
Bienert
Diagramm
Thema
Projektleiter
Bearbeiter
Projekt
EA - Elektro
Automatik
Art. Nr.
Datei : H:\dos\technik\Projekte\EL3000-9000A\Messungen & Tests\messung ue zu ie an el3000.vsd
CAD Sys. MS-Visio
Measurings EL3160-60
Current
Voltage
60A
1,35V
45A
0,97V
30A
0,63V
15A
0,32V
Measurings EL3400-25
Current
Voltage
25A
0,95V
20A
0,74V
10A
0,36V
5A
0,18V
I
in
/A
U
in
/V
20
15
10
5
0,5
1
1,5
25
Resistance regulation (U
in
/I
in
ratio)
25A load
I
in
/A
U
in
/V
60
45
30
15
1
1,5
Resistance regulation (U
in
/I
in
ratio)
60A load
0,5
Measurings EL3160-60
Current Voltage
60A
1,35V
45A
0,97V
30A
0,63V
15A
0,32V
Measurings EL3400-25
Current Voltage
25A
0,95V
20A
0,74V
10A
0,36V
5A
0,18V
