NORD Drivesystems BU0230 - Manual (Page 45)

3 Assembly and installation
BU 0230 GB-2712 45
3.6.1 Details of the 24V supply
Terminal/
Name
Function
[factory setting]
Data Description / wiring suggestion Parameter
SK 205E, SK 215E, SK 225E, SK 235E
44 24V 24 V Supply
(module and system bus
level)
24 VDC -/+25 %
(-10 % / +25 % at OSSD)
200 mA ... 800 mA
according to load on the
FI, the inputs and outputs
or equipment with options
Supply voltage connection for the
FI control unit and the output DO1
-
40 GND Reference potential
for the 24 V supply
and the digital
signals
-
3.6.2 Operation at OSSD
The 24 V supply is not specifically designed for supply via an OSSD. However, it may be operated from an
OSSD if the following restrictions are taken into account.
A resistor is located in the inverter, in order to discharge the cable with a test pulse from an OSSD. We
recommend that a capacitance of 2 nF * t
OSSD
/ 0,1 ms (including shielding capacitance) per connected
inverter is not exceeded. (with t
OSSD
= Width of test pulse, max. 0.5 ms)
Additional restrictions may apply here with regard to the protective switching device.
As with operation from an OSSD, there is an interruption in the supply during a test pulse, the supply voltage
inside the device reduces during the test pulse. In order to ensure correct operation, the resistance of the
connected cable (internal resistance of the source) should not exceed the values in the following diagram.
maximaler Leitungswiderstand
0,0Ω
0,5Ω
1,0Ω
1,5Ω
2,0Ω
2,5Ω
3,0Ω
3,5Ω
20,0V 20,5V 21,0V 21,5V 22,0V 22,5V 23,0V 23,5V 24,0V
Quellenspannung
I_DO1<=20mA =100mA =200mA
The permissible cable resistance depends on the source voltage and the load from the digital output DO1.
Even with larger source voltages (up to 30 V) it should not exceed a value of 3 Ohm.
Operation from an OSSD is possible above a source voltage of 20 V. However, a source voltage of at least
21.6 V is recommended. Especially if several inverters are connected to a protective switching device, care
must be taken that there is at least 21.6 V at the terminals of the inverter.
With operation from an OSSD, both the mains unit and the digital output DO1 are supported by the input
capacitors during a test pulse. After the test pulse, the supporting capacitance (200 µF) is recharged by means
of the relatively large peak current. The graphs shown here show theoretical maxima (for an inverter with
power 7.5 kW, 400 V). In practice, the currents are somewhat lower.
Maximum cable resistance
Source voltage