User manual

Page 26
EL 9000 T Series
www.elektroautomatik.de
[e-mail]
EA Elektro-Automatik GmbH
Helmholtzstr. 31-37 • 41747 Viersen
Germany
Fon: +49 2162 / 3785-0
Fax: +49 2162 / 16230
Seethediagramsbelowforclarication.
0s 40s 80s
...
210s
Peak power
Steady power
400W
450W
500W
550W
600W
Principle derating progression
The maximum power is absorbed by the load device for a time
x, before derating starts. After the start of derating, the available
input power of the load will settle around the point as given in the
technical for 40°C ambient. The true input power can be read
from the device’s actual power value (display or via interface). In
case the ambient temperature rises, the derating will continue.
blue: 80 V model
red: 200 V model
green: 500 V model
3.2.5 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 band-
width 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 complete system (feeding source and electronic load) has too
littlephaseandgainmarginatcertainfrequencies.180°phaseshiftat>0dBamplicationfulls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 inductive or inductive-capacitive.
The instability is not caused by a malfunction of the load, but by the behaviour of the complete system. An improve-
ment of the phase and gain margin can solve this. In practice, a capacity is directly connected to the DC input of
theload.Thevaluetoachievetheexpectedresultisnotdenedandhastobefoundout.Werecommend:
80Vmodel:1000μF....4700μF
200Vmodel:100μF...470μF
500Vmodel:47μF...150μF