T Series Data Sheet
500 Watt AC-DC Converters
Features
• RoHS lead-free-solder and lead-solder-exempted
products available
• Universal AC input range 70 to 255 VAC with PFC
• Class I equipment
• DC output for 24 and 48 V loads
• Battery charging for 24 and 48 V batteries with remote
temperature control
• 4 kVAC I/O electric strength test voltage
• Telecom rectifier applications
• Very high efficiency, typically 93%
• Power factor >0.96, harmonics according to IEC/EN
61000-3-2, low RFI
• No inrush current, hot swap capability
• High power density, rugged mechanical design, all
boards covered with a protective lacquer
• Very compact 19" cassette (28 TE, 3 U, 160 mm)
Safety according to IEC/EN 60950-1 and UL/CSA
60950-1 2
nd
Ed.
111
4.4"
3U
141
5.6"
28 TE
168
6.6"
Description
The T Series converters are electrically isolated AC-DC
converters with an output power of up to 550 W. For higher
power requirements several converters may be connected in
parallel.
The input is ideally adapted to the mains: Full power factor
correction, no inrush current, low RFI level, and high transient
and surge immunity are key design features. A T Series
converter behaves similar to a resistive load.
The LT models can be operated from a universal AC-input
range from 85 to 255 VAC. It is the preferred type for 230 VAC
mains, whereas the UT models are optimized for 110/120 VAC
mains. The output delivers an electrically isolated Safety Extra
Low Voltage (SELV) and is short-circuit and no-load proof.
Depending on the type, two output characteristics are
available, intended either for rectifier applications or for battery
charging purposes.
The latter types can be integrated into systems, where the
output voltage is backed-up by a battery. The float charge of the
battery can be set by a cell-voltage selector switch according to
the battery type used. These converters are equipped with a
temperature sensor input, in order to improve the life
expectancy of the battery.
The rectifier models are suited for DC-bus applications at
constant voltage. As the output voltage is SELV, even
electrically non-isolated switching regulators, such as the PSx
models, may be connected to the output.
The LT/UT1701 models are especially optimized to build
distributed power systems together with the 48Q, CQ, or CP
Series DC-DC converters, as the signaling capabilities of both
families are matched. Distributed power systems have as one
advantage less power losses over load lines and fewer
regulation problems.
Bel Power Solutions also offers backplanes for fast and simple
set-up of 19" DIN-rack systems with T Series converters; see
Accessories.
Table of Contents
Page
Page
Different Configurations and Applications .........................
Electromagnetic Compatibility (EMC) ...............................
Environmental Conditions .................................................
Mechanical Data ...............................................................
Safety and Installation Instructions ...................................
Description of Options ......................................................
Accessories .......................................................................
18
21
22
24
25
28
29
Description .......................................................................... 1
Model Selection .................................................................. 2
Functional Description ........................................................ 3
Electrical Input Data ............................................................ 4
Electrical Output Data ......................................................... 6
Control Features of the Battery Chargers .......................... 11
Auxiliary Functions ............................................................ 13
Copyright © 2015, Bel Power Solutions Inc. All rights reserved.
MELCHER
BCD20023-G Rev AD, 29-Jul-2015
The Power Partners.
Page 1 of 31
T Series Data Sheet
500 Watt AC-DC Converters
Model Selection
Table 1: Model types LT and UT.
Output voltage
V
o set
at
V
i nom
, 0.5
I
o nom
[VDC]
24.25
25.25 – (27.25) – 28.25
30.5
45.5
48
54.5
50.5 – (54.5) – 56.5
1
2
3
4
5
6
Output current
I
o nom
[A]
16
14.5
15.5
10
11
10
10
Operating input voltage range and efficiency
V
i min
–
V
i max
70 – 140 VAC
UT1201-7
2, 4
UT1240-7Z
3, 4
UT1404-7
2, 5
–
–
UT1701-7
5
UT1740-7Z
3, 5
η
min 1
[%]
91
91
91
–
–
92
92
V
i min
–
V
i max
85 – 255 VAC
LT1201-7
2, 6
LT1240-7Z
3, 6
–
LT1804-7
6
LT1702-7
6
LT1701-7
6
LT1740-7Z
3, 6
η
min 1
[%]
90.5
91
–
91.5
92.5
92.5
92
Options
D
B1
G
Min. efficiency measured at
V
i nom
and
I
o nom
; typ. values are approx. 1% better.
Instead of output power limitation, output current limitation.
Output voltage range controlled by input
V
cr
, remote temperature sensor, and cell voltage selector switch.
Reduced output power for
V
i
= 70 – 95 VAC; see
Output Power Limitation.
Reduced output power for
V
i
= 70 – 100 VAC; see
Output Power Limitation.
Reduced output power for
V
i
= 85 – 155 VAC; see
Output Power Limitation.
NFND: Not for new designs.
Preferred for new designs
Part Number Description
Operating input range
V
i
, f
i
70
–
140 VAC, 47
–
63 Hz ............................ U
85
–
255 VAC, 47
–
63 Hz ............................ L
Series
...................................................................... T
Number of outputs ............................................................ 1
Output setting voltage
V
o set
24, 27.25 V ................................................... 2
48, 54.5 V ..................................................... 7
40.9 V ........................................................... 8
Rectifier version .................................... 01, 02
Battery charger version .............................. 40
Other voltages ................................... 00 to 99
Ambient temperature range
T
A
–25
to
71 °C ................................................. -7
Customer-specific models ................. -0 to -6
Auxiliary functions and options
1
Undervoltage monitor (option) ...................... D
Cell voltage selector switch .......................... Z
Baseplate (option) ...................................... B1
RoHS compliant for all six substances ........ G
1
2
3
4
L T 1 7 40 -7 D Z B1 G
3
4
2
See
Description of Options.
Contact the Company for avalebility and lead times !
Only for T1240/1740/1840
No input for battery temperature sensor
With input for battery temperature sensor
Note:
The sequence of options must follow the order above.
Example:
LT1740-7 Z: AC-DC converter, input voltage range 85 – 255 VAC, single output 50.5 – 56.5 V, 10 A,
operational ambient temperature –25 to 71 °C, with cell voltage selector switch.
Specific type designation, input voltage range, nominal output
voltage and current, degree of protection, batch no., serial no.,
and data code including production site, version, and date of
production.
Product Marking
Basic type designation, applicable safety approval and
recognition marks, CE mark, warnings, pin designation,
Company logo.
BCD20023-G Rev AD, 29-Jul-2015
MELCHER
The Power Partners.
Page 2 of 31
T Series Data Sheet
500 Watt AC-DC Converters
Functional Description
The T Series AC-DC converters are primary controlled with a
constant switching frequency of 65.5 kHz. The power factor
corrected single step conversion of the line input voltage to a
low output voltage results in extremely high efficiency.
The input voltage is fed via input fuse, filter, and rectifier to the
main transformer. The wideband input filter with small input
capacitance generates virtually no inrush current. Transient
suppressors protect the converter against overvoltage and
surges. An auxiliary converter generates an internal supply
voltage for the primary control logic. The input voltage
waveform is sensed by the primary control logic to provide
active power factor correction.
The main transformer is connected to a rectifier, large output
capacitors, and an efficient output filter, which ensures low
output ripple and spikes, and provides the necessary hold-up
time. The output voltage is fed back to the primary control logic
via a signal transformer.
The inhibit signal and the T failure signal are transferred by a
second signal transformer (no optocouplers are used !).
System Good and Output OK are each indicated by a green
LED; inhibit and T System Failure by a red LED.
System Good and Power Down are available as open collector
signals at the connector. The threshold level of the Power
Down signal can be externally adjusted at the D set input.
Test sockets at the front panel allow for the measurement of the
output voltage.
The battery charger version provides additional features to
control the output voltage. To set it to different battery float-
charge voltages, a 16-step selector switch (Z) is standard.
A control input to control the output voltage by an external
temperature sensor is available at a control pin. A trim-
potentiometer allows fine adjustment of the output voltage.
–
C
y
12
Vo+
14
Vo+
03043a
Fuse
Output filter
Input filter
Input filter
Input filter
L~
4
N~
6
Isolation 4 kVAC
8
10
C
y
C
y
C
y
Auxiliary
converter
C
y
Control
logic
Voltage
and
system
monitor
Z
P
Fig. 1
Block diagram
MELCHER
BCD20023-G Rev AD, 29-Jul-2015
The Power Partners.
+
16
HC+
NTC
18
HC –
20
Vo–
C
y
22
Vo–
24
Sys In
26
Sys Out
28
i/Vcr
30
D
32
D set
Page 3 of 31
T Series Data Sheet
500 Watt AC-DC Converters
Electrical Input Data
General condition:
T
A
= 20 °C
Table 2a: Input data of LT models
Input
Characteristic
V
i
V
i red
Operating input voltage range
with full output power
Operating input voltage range
with reduced output power
1
50 – 60 Hz
2
V
i nom
,
P
o nom
V
i min
–
V
i max
,
I
o
= 0
V
i min
–
V
i max
, inhibit = low
V
i nom
,
I
o nom
96
4
V
i nom
,
P
o nom
V
i nom,
V
o nom,
I
o nom
EN 55022
400
A
A
264
65
Conditions
47 – 63 Hz
2
min
155
85
100
(230)
1.9
3
6
3
98
4
400
A
A
264
65
LT12xx
typ
max min
255 155
155
85
(230)
2.6
4
8
3
98
4
400
A
A
264
65
VAC
LT17xx
typ
max min
255 130
155
85
(230)
2.2
4
8
3
%
µF
ms
W
LT18xx
typ
max
255
130
240
A
VAC
Unit
V
i
(V
i nom
) Rated (nominal) input voltage
I
i nom
I
i L
P
i 0
P
i inh
PF
C
i
t
on
Nominal input current
Input current limit
No-load input power
Input power when inhibited
Power factor
Input capacitance
3
Switch on delay
Conducted emissions
Radiated emissions
V
i p
V
i L
Input overvoltage protection
4
Input undervoltage lockout
240 100
240 100
Table 2b: Input data of UT models
Input
Characteristic
V
i
V
i red
Operating input voltage range
with full output power
Operating input voltage range
with reduced output power
1
50 – 60 Hz
2
V
i nom
,
P
o nom
V
i min
–
V
i max
,
I
o
= 0
V
i min
–
V
i max
, inhibit = low
V
i nom
,
I
o nom
98
4
V
i nom
,
P
o nom
V
i nom,
V
o nom,
I
o nom
EN 55022
400
A
A
165
65
Conditions
47 – 63 Hz
2
min
95
70
100
(110)
3.8
5
6
3
98
4
400
A
A
165
65
VAC
UT12xx
typ
max
140
95
125
min
95
70
100
(110)
5.2
6
8
3
%
µF
ms
W
UT17xx
typ
max
140
100
125
A
VAC
Unit
V
i
(V
i nom
) Rated (nominal) input voltage
I
i nom
I
i L
P
i 0
P
i inh
PF
C
i
t
on
Nominal input current
Input current limit
No-load input power
Input power when inhibited
Power factor
Input capacitance
3
Switch on delay
Conducted emissions
Radiated emissions
V
i p
V
i L
1
2
3
4
Input overvoltage protection
4
Input undervoltage lockout
See
Output Power Limitation
Contact the Company for operation with other input frequencies or different waveforms !
Inrush current stays factor 10 below ETS 300132-1.
In the case of an overvoltage, the converter switches temporarily off, resulting in reduced output power.
MELCHER
BCD20023-G Rev AD, 29-Jul-2015
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Page 4 of 31
T Series Data Sheet
500 Watt AC-DC Converters
Input Fuse
An input fuse (5
×
20 mm) in series with the input line (L)
inside the converter protects against severe defects; see also
Safety and Installation Instructions.
For applications with
accessible fuse, see
Option F.
Table 3: Fuse Type
Series
LT
UT
Schurter type
SPF 6.3 A, 250 V
SPT 10 A, 250 V
Part number
0001.1012
0001.2514
2.0
1.5
1.0
0.5
0
3
5
7
9
11
13
15
17
Harm.
Limit class D according
to IEC/EN 61000-3-2
mA/W
3.5
3.0
2.5
04026a
Inrush Current
The converters exhibit an input capacitance of only 4 µF,
resulting in a low and short peak current, when the converter
is connected to the mains. During switch-on, the converter
current can rise up to the input current limit
I
i L
.
As a direct result of the low and short inrush current and
controlled charging procedure of the output capacitors, the
converter can be hot swapped. The LT inrush current is a
factor 10 smaller than defined in the ETS 300132-1 standard
for Telecom systems. However the converter should be
plugged-in smoothly, giving time to the output capacitors to be
charged.
Fig. 3
Harmonic distortion at input LT1740-7Z, V
i
= V
inom
, I
o
= I
o nom
mA/W
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
3
5
7
9
11
13
15
Limit class D according
to IEC/EN 61000-3-2
04025a
Input Under- /Overvoltage Lockout
If the specified input voltage range
V
i
is exceeded, the
converter stops operation temporarily resulting in reduced
output power and increased RFI. The input is protected by
varistors. Continuous overvoltage will destroy the converter.
If the sinusoidal input voltage stays below the input under-
voltage lockout threshold
V
i
, the converter will be inhibited.
Power Factor, Harmonics
Power factor correction PFC is achieved by controlling the
input current waveform synchronously with the input voltage.
17
Harm.
Fig. 4
Harmonic distortion at input UT1740-7Z, V
i
= V
inom
, I
o
= I
o nom
PF
1.00
0.98
0.96
0.94
0.92
0.90
0.88
0.86
0.84
0.82
04023a
0.96
0.94
0.92
0.90
0.88
0.86
0.84
0.82
04024a
I
o
[A]
0
2
4
6
8
10
UT1740-7Z at
V
i
= 110 VAC
LT1740-7Z at
V
i
= 230 VAC
12
14
16
0
2
4
6
V
i
= 110 VAC
8
10
12
14
U
i
= 230 VAC
16
I
o
[A]
Fig. 2
Power factor
BCD20023-G Rev AD, 29-Jul-2015
Fig. 5
Efficiency versus load of LT1701
MELCHER
The Power Partners.
Page 5 of 31