EN
QTD20.241 Installation Manual
Product Description
The QTD20.241 is a DIN-rail mountable DC/DC converter, which provides a floating, stabilized and
galvanically separated SELV/PELV output voltage.
Intended Use
This device is designed for installation in an enclosure and is intended for commercial use, such as in
industrial control, process control, monitoring and measurement equipment or the like.
This device is optimized to operate from the intermediate bus of a drive system. It can cope with the
EMI disturbances on such busses.
Do not use this device in equipment, where malfunctioning may cause severe personal injury or
threaten human life without additional appropriate safety devices, that are suited for the end-
application.
If this device is used in a manner outside of its specification, the protection provided by the device may
be impaired.
Installation Instructions
Install device in an enclosure providing protection against electrical, mechanical and fire hazards.
Install the device onto a DIN-rail according to EN 60715 with the input terminals on the bottom of the
device. Other mounting orientations require a reduction in output current.
Make sure that the wiring is correct by following all local and national codes. Use appropriate copper
cables that are designed for a minimum operating temperature of 60°C for ambient temperatures up to
+45°C, 75°C for ambient temperatures up to +60°C and 90°C for ambient temperatures up to +70°C.
Ensure that all strands of a stranded wire enter the terminal connection. Use ferrules for wires on the
input terminals.
The device is designed for pollution degree 2 areas in controlled environments. No condensation or
frost is allowed.
The enclosure of the device provides a degree of protection of IP20. The enclosure does not provide
protection against spilled liquids.
The isolation of the devices is designed to withstand impulse voltages up to 4kV according to IEC
60664-1.
The device is designed as “Class of Protection I” equipment according to IEC 61140. Do not use
without a proper PE (Protective Earth) connection.
The device is designed to be supplied from a DC input voltage derived from a 3-phase mains network
by means of a B6 bridge rectifier. The device is not designed to be used on corner grounded delta
systems. Follow the wiring scheme option 1 shown in this document.
The input can also be supplied by batteries or similar DC sources. Since the continuous voltage
between the input voltage and the PE/earth potential must not exceed 440V r.m.s., the input voltage
must be grounded at about half the supply voltage as shown in option 2 in the wiring scheme drawing.
Do not ground the positive or negative input voltage pole.
Check for correct input polarity. The device will not operate when the voltage is reversed.
A disconnecting means shall be provided for the input of the device.
The device is designed for convection cooling and does not require an external fan. Do not obstruct
airflow and do not cover ventilation grid!
The device is designed for altitudes up to 5000m (16400ft).
Keep the following minimum installation clearances: 40mm on top, 20mm on the bottom, 5mm left and
right side. Increase the 5mm to 15mm in case the adjacent device is a heat source. When the device
is permanently loaded with less than 50%, the 5mm can be reduced to zero.
The device is designed, tested and approved for branch circuits up to 16A (IEC) and 15A (UL) without
additional protection device. If an external fuse is utilized, do not use circuit breakers smaller than 6A
B- or 3A C-Characteristic to avoid a nuisance tripping of the circuit breaker.
The maximum surrounding air temperature is +70°C (+158°F). The operational temperature is the
same as the ambient or surrounding air temperature and is defined 2cm below the device.
The device is designed to operate in areas between 5% and 95% relative humidity.
Functional Description
The output is electronically protected against no-load, overload and short circuit and can supply any
kind of loads, including unlimited inductive and capacitive loads.
Do not apply return voltages from the load to the output terminals higher than 34V.
The output voltage can be adjusted with a small flat-blade screwdriver behind the flap on the front.
The green DC OK LED reports an output voltage above 90% of the adjusted voltage of a running
device.
The DC OK relay monitors the output voltage and the contact is closed when the DC-OK LED is on.
Contact ratings: 60Vdc 0.3A, 30Vdc 1A, 30Vac 0.5A for resistive loads.
The red overload LED is on when the output voltage falls below 90% of the adjusted value or in case
of a short circuit in the output or too high temperature. Input voltage is required.
The device is equipped with an over-temperature protection. In case of a high temperature, the output
shuts down and starts automatically again after cooling off.
Devices can be paralleled to increase the output power. The ambient temperature is not allowed to
60°C. The output voltage shall be adjusted to the same value (±100mV) with the same load
conditions on all devices, or the devices can be left with the factory settings. If more than three
devices are connected in parallel, a diode, fuse or circuit breaker with a rating of 25A is required on
each output.
Same devices can be connected in series for higher output voltages. It is allowed to connect as many
devices in series as needed, providing the sum of the output voltage does not exceed 150Vdc.
In case of an internal defect, a redundant circuit limits the maximum output voltage to 35V. The output
shuts down and automatically attempts to restart.
Technical Data
All values are typical figures specified at 600Vdc input voltage, 24V, 20A
output load, 25°C ambient and after a 5 minutes run-in time unless
otherwise noted.
Output voltage
DC 24V
Nominal
Adjustment range
24 – 28Vdc
Factory setting 24.1V
Output current
Continuous:
20 – 17.5A
Below +60°C ambient
15 – 13.1A
At +70°C ambient
Short-term, up to 4s:
25 – 21.4A
Below +70°C ambient
Derate linearly b60°C and +70°C
Input voltage
DC 600V
-20%/+40%
Input current
0.85A
Input inrush current
1.6A peak
Temp. independent
Efficiency
95.0%
Losses
25.5W
Hold-up time
22ms
Temperature range
-25 to +70°C
Max. wire size (litz wire)
4mm²
Wire size AWG
AWG 20-10
Max. wire diameter
2.8mm
Wire stripping length
10mm / 0.4inch
Size (wxhxd)
65x124x127mm Without
DIN-rail
Weight
890g / 1.96lb
Functional Diagram
+
+
-
-
Output
Over-
Voltage
Protection
Input Filter
Inrush Current
Limiter
Transient Filter
Voltage
Regulator
Power
Converter
Output
Filter
Output
Power
Manager
Temper-
ature
Shut-
down
Input
Fuses
V
OUT
DC-OK
Contact
DC-OK
LED
DC-ok
Relay
13
14
Overload
LED
+
-
Output Characteristic
Output voltage
24V
Output current
0V
5A
15A
20A
25A
0A
Adjustment range
28V
10A
30A
B
A
A: continuous
B: for 4s
Temperature Range
Allowed output current at 24V
Ambient temperature
0A
-25
A: continuous
B: short term (typ. 4s)
25A
0
+70°C
15A
B
20A
+60
A
Wiring Scheme
I max 16A
L1
L2
L3
DC/DC
Converter
IN
OUT
+
-
+
-
DC
24V
DC
600V
PE
IN
OUT
+
-
+
-
DC
24V
DC
600V
PE
DC/DC
Converter
DC/DC
Converter
IN
OUT
+
-
+
-
DC
24V
DC
600V
PE
IN
OUT
+
-
+
-
DC
24V
DC
600V
PE
DC/DC
Converter
U/2
U/2
Option 1:
Option 2:
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