nextys NPS2400 User manual

NPS2400
2400W High Efficiency Power Supply
User’s Manual

NPS2400 User’s Manual Rev. 2.5 – 25 July 2013 Page 2/37
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including “Typicals", must be validated for each customer application by
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change without notice.

NPS2400 User’s Manual Rev. 2.5 – 25 July 2013 Page 3/37
TABLE OF CONTENTS
1Revision History......................................................................................................................................................................3
2Acronyms................................................................................................................................................................................3
3Introduction.............................................................................................................................................................................4
4Functional description.............................................................................................................................................................6
5Installing the NPS2400 ...........................................................................................................................................................7
5.1 General considerations.....................................................................................................................................................7
5.2 Mounting and dismounting the device..............................................................................................................................8
5.3 Connecting the device......................................................................................................................................................9
5.4 Maintenance...................................................................................................................................................................17
6Operating modes ..................................................................................................................................................................17
6.1 Overboost mode (default)...............................................................................................................................................17
6.2 Constant current limit mode............................................................................................................................................18
6.3 Battery charger mode (available only on “-24” and “-48” models)...................................................................................19
7User interface .......................................................................................................................................................................20
7.1 Principles of operation....................................................................................................................................................20
7.2 Contrast adjustment .......................................................................................................................................................21
7.3 Initial and standard screens............................................................................................................................................21
7.4 Set-up menu...................................................................................................................................................................23
7.5 Measurements................................................................................................................................................................28
7.6 Event log ........................................................................................................................................................................29
7.7 Information .....................................................................................................................................................................34
8Technical specification..........................................................................................................................................................35
8.1 Input ...............................................................................................................................................................................35
8.2 Output.............................................................................................................................................................................35
8.3 Interface .........................................................................................................................................................................35
1 Revision History
Revision Date Author Comments
1.0 11/04/2011 Ramon Zambelli First draft
2.0 13/12/2011 Ramon Zambelli Second issue
2.1 28/02/2012 Marco Geri Final review
2.2 27/03/2012 Ramon Zambelli Added buzzer in front view image
2.3 10/07/2012 Ramon Zambelli Added edit device name menu item
2.4 08/11/2012 Marco Geri Corrected output voltage range
2.5 20/06/2013 Marco Geri Corrected dielectric strength values
2 Acronyms
Acronym Definition
SMPS Switching Mode Power Supply.
NPS2400_CB NPS2400 Communication board. Used to interface a PC to the SMPS.
PFC Power Factor Corrector
PE Protective Earth
SELV Safety Extra Low Voltage
PELV Protective Extra Low Voltage
FW Firmware

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3 Introduction
The NPS2400x series is a high power, high performance, CPU controlled 3-phase input SMPS family.
These products present many advanced features such as:
Very high efficiency (>92%)
Compactness
PFC input
Operating also with DC input
Wide range of output voltage
Integrated active ORing circuit for all models
Increased input protection against various mains abnormalities (overvoltage, surge, micro-interruptions, etc.)
Remote shutdown
Voltage sense function
4-20 mA and 0-10 V output current remote measurement
User programmable auxiliary dry contact
Load share (up to 4 units can be paralleled for redundancy or power increase)
3 operating modes:
oOverboost which can deliver up to 150% of the rated current for a maximum of 5 seconds
oConstant current
oLead-acid battery charger (only on “-24” and “-48” models) with temperature compensation
Microcontroller based for:
oMonitoring
oOperating control and supervision
User interface
oEmbedded user interface (4 user buttons, 2 LEDs and 1 LCD display):
Displays real time status and alarms
History of events, time stamped (a Real Time Clock is implemented)
oPC application through USB interface (using an optional interface box NPS2400_CB):
Remote configuration of the device
Firmware upgrade
Same functionalities of the embedded user interface with the ease of the PC benefits
The NPS2400x family includes 4 models with 4 different output voltages and current ratings for a rated power of 2400 W (peak
overload power of 3600 W).
Model name Rated Vout [VDC] Vout min [VDC] Vout max [VDC] Rated Iout /Ipeak[A] Rated /peak power [W]
NPS2400-24 24 11.5 29 100 / 150 2400 / 3600
NPS2400-48 48 23 56 50 / 75 2400 / 3600
NPS2400-72 72 50 87 33 / 50 2400 / 3600
NPS2400-170 170 85 175 14 / 21 2400 / 3600
Table 1 Models ratings

Figure 1 shows a front view of the SMPS with a short description of the main elements.
Figure 1 NPS2400 front view
Figure 2 shows the auxiliary connector I/Os.
Figure 2 Auxiliary connector I/Os
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4 Functional description
A simplified block diagram of the NPS2400 is shown in Figure 3.
Figure 3 NPS2400 simplified block diagram
NPS2400 is a 3-phase input SMPS with 2 power stages, supervised by a microcontroller. The first stage is a power factor
corrector (PFC) module that improves unit efficiency and reduces the harmonic current from the mains. The second stage is a
resonant full bridge converter that provides primary to secondary insulation and high efficiency power conversion.
The product offers additional features that improve the performances and the reliability:
Integrated active ORing diode: allows connecting several devices in parallel for redundancy (see §5.3.4). When several units
are paralleled for increase of the total output power (up to 8.7kW) this circuit increases the reliability of the system in case of 1
unit failure.
Load share functionality: allows connecting up to 4 devices in parallel to increase the output power up to 8.7kW. A dedicated
bus allows to equally share the total load current between the paralleled devices.
Remote voltage sensing: allows regulating the output voltage directly at the load terminals compensating the cables and
connectors voltage drop when long cables are used.
Active surge protection: this circuit increases the reliability by protecting the device from high voltage transients occasionally
present on the 3 phase mains. On top of that this circuit performs also the function of active inrush current limiter reducing the
inrush current to very low values.
Smart thermal management:the fans’ speed is controlled according to load and internal temperature conditions. This allows
maintaining a safe temperature of the critical parts while maximizing the fans operating life and minimizing the fans noise.
Remote output current measure: the user can measure remotely the output current delivered by the SMPS. The information is
provided through an opto-isolated output with 2 industry standard ranges: 0…10V or 4…20mA for 0A to rated output current.
Remote shutdown input: it allows to remotely switch the SMPS ON or OFF without cutting the 3 phase mains. An opto-isolated
input can be configured as a remote shutdown/enable input
Auxiliary 12V output: the units provide a regulated 12V/0.1A output completely insulated from the main output. It can be used
to supply light 12V loads, independently on the SMPS output voltage/status.
Battery charger mode (only on “-24” and “-48” models): this operating mode allows operating the device as a high
performance battery charger for lead-acid batteries. 12V, 24V or 48V batteries can be charged up to a capacity of 1000Ah.

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5 Installing the NPS2400
5.1 General considerations
LWarning: NPS2400 is a high voltage and high current SMPS. In order to avoid potentially hazardous situations
including fire hazard, safety recommendations must be followed. Only authorized staff can install the unit.
5.1.1 Input voltage
Vin= 3x400…500VAC (range=340…550VAC) or 520…750VDC. Use with only 2 phases connection is prohibited. Under
emergency conditions only the units can operate with 2 phases input with reduced maximum power to ½ of the nominal.
Connect the Earth (PE) wire before connecting L1/L2/L3 wires and keep it as short as possible. The wire gauge should be at
least 1.5 mm2(15 AWG).
5.1.2 Input protection devices
NPS2400 is NOT equipped with an internal protection fuse. Use external breaking and protection devices as circuit breakers
rated 10A and characteristic C, properly rated for the operating voltage and with a minimum breaking power of 1.5kA. Over-
Current protection must be provided on each phase.
For USA and Canada use fuses class CC rated 10A. In some countries local regulation may apply.
Special ratings and devices should be used for DC input applications. Call factory for information.
5.1.3 Input connector wiring
The input mains terminal block accepts wires up to 4mm2(11AWG). Strip the wire insulation for 8mm, screw tightening torque
0.5…0.6Nm, use only 60/75 Class 1 copper wires.
LWarning: before operating on the device disconnect the AC mains and wait at least 1 minute.
5.1.4 Output connector wiring
The output terminal block accepts wires up to 35mm2(2AWG). Strip the wire insulation for 15mm, screw tightening torque
2.5…4.5Nm, use only 60/75 Class 1 copper wires. Refer to Table 1 to define the minimum wire gauge for each model.
Model name Rated Vout [VDC] Rated Iout [A] Minimum wire gauge [mm2/AWG]
NPS2400C 24 100 25 / 3
NPS2400D 48 50 10 / 7
NPS2400G 72 33 6 / 9
NPS2400R 170 14 2.5 / 13
Table 2 Recommended output wire gauge
5.1.5 Auxiliary connector wiring
The auxiliary terminal block accepts wires from 0.5mm2 (20AWG) to 1.5mm2(15AWG). Strip the wire insulation for 5mm, screw
tightening 0.25Nm, use only 60/75 Class 1 copper wires.
5.1.6 Cooling
Mount the device in vertical position, keep at least 80mm (3inch) free spacing on upper and lower side, 10mm (0.4inch) free
spacing between adjacent devices. Check periodically that the air inlets in the enclosure are free from dust and other debris that
can obstruct the air flow.
Mount the device in the cooler zone of the cabinet. The thermal protection is activated if the surrounding air temperature is
>50°C (122 °F) along with continuous full load operation. The device restarts automatically after cooling down.

5.2 Mounting and dismounting the device
5.2.1 Mounting the device
1
2
Figure 4 Mounting the device on DIN rail
Snap on the device on IEC60715/H35-7.5 rail; push the bottom side of the device towards the rail. The device will be
automatically locked to the rail.
5.2.2 Dismounting the device
1 2
3
Figure 5 Mounting the device on DIN rail
Pull down the slide using a screwdriver and then free the bottom part by rotating the device upwards.
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5.3 Connecting the device
5.3.1 Standard connection
Figure 6 Standard device connection
Figure 7 Standard device connection
This is the basic configuration: connect the mains and the load using wires of appropriate gauge as stated in §5.1.
L Check the polarity of the output load before applying mains.
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5.3.2 Connection with remote voltage sense
Figure 8 Connection using remote voltage sense
When the load is placed far away from the SMPS or when tight voltage accuracy is needed by the load, the NPS2400 provides
a feature to compensate the output cables I*R voltage drop. It can tightly regulate the output voltage directly at the load
terminals and not at the SMPS output terminal, within 10mV of precision.
For applying this feature 2 additional cables (any flex wire from 0.5mm2 /20 AWG to 1.5mm2/15 AWG) are connected from the
load terminals to the SMPS auxiliary connector SENSE+ and SENSE- terminals.
It is strongly recommended to twist the 2 wires together in order to improve the noise and interference immunity.
L Please check and respect the polarity of the sense wires! If the polarity is reversed the SMPS output voltage
of the SMPS will increase to its maximum. Although not harmful for the SMPS itself (an output overvoltage
error will be triggered) this condition can damage the load.
Note 1: The voltage displayed on the LCD screen is always the voltage at the SMPS output and not the voltage at the load
terminals.
Note 2: In case of very long output cables with consistent I*R cable drop the device could no more be able to deliver the rated
output current. The rated output power is however maintained.
Example: Vload=24V, cable drop=0.5 V (per cable), voltage at SMPS output=24V+2*0.5V=25V Maximum output
current=2400W/25 V=96A (not 100A!).
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5.3.3 Connection in series
Figure 9 Connection of multiple units in series
The series connection allows increasing the total output voltage. Connect the output terminals of each device in series checking
the right polarity.
Note 1: Before any power ON be sure to have connected the antiparallel diodes to all units. The voltage rating of EACH
diode should cover the TOTAL voltage of the SERIES system. A diode as P600J is suitable for most applications.
Note 2: Only SMPS of the same model (same rated output voltage) can be connected in series. Do not exceed > 4
units connected in series and > 200Vdc total voltage. For other situations contact the factory.
Note 3: To achieve the best power sharing between the series connected devices it is recommended to regulate the
output voltage of each device at the same value with a tolerance of maximum 0.1V.
Note 4: When using several devices in series the operating mode must be set to OVERBOOST, using CONSTANT
CURRENT mode can result in instabilities in case of load short circuit. The maximum current setpoint shall be the
same on every connected device.
:
L When the units are used in series do not connect anything to the auxiliary connector SENSE+/SENSE- and
SHARE+/SHARE-. Any connection to these signals may damage the units and the connected load.
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5.3.4 Connection in parallel (power and redundancy)
Figure 10 Connection of multiple units in parallel
The parallel connection may have one of the following purposes:
1) Redundancy: several units (unlimited number in theory, 2...4 units in practice) can be used to increase the system
reliability. If one SMPS fails the load will be still powered from another SMPS connected in parallel. The NPS2400
integrates an active ORing diode so that several units can be directly connected in parallel without the need for an
external ORing module. In this configuration the maximum power sunk by the load must be < Pnom. The
SHARE+/SHARE- signals should NOT be connected.
2) Power increase: this configuration is used to increase the system power capacity by summing the output current of
each individual SMPS connected in parallel to the load. To obtain the system’s best performance SHARE+/SHARE-
signals must be daisy chain connected on all SMPS’. This allows equal current sharing between all the SMPS’.
Note 1:When used in parallel for power increase the maximum number of SMPS is 4 units.
Note 2:When used in parallel for power increase the maximum total output current will be 0.9*Iout*N, where N is the number
of connected SMPS’. The maximum power is thus limited to 0.9*N*Pnom<8.7kW.
Note 3:To achieve the best power sharing between the parallel connected devices the output voltage of each device must be
adjusted at the same value with a tolerance of maximum 0.2V. The share bus will then slightly vary the output voltage
of each SMPS to achieve the best possible power sharing.
L Do not connect anything to the auxiliary connector SENSE+/SENSE- when using the SHARE+/SHARE-
connection! Wrong connection to these signals may damage the devices and the connected load.
LRespect the polarity of the SHARE+/SHARE- connections!
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5.3.5 Battery charger connection (only on “-24” and “-48” models)
Figure 11 Connection when used as battery charger
The “-24” and “-48” models feature a function of battery charger, “-24” model can charge 12V and 24V batteries with capacity
from 50Ah to 1000Ah while “-48” model can charge 48 V batteries only with capacity ranging from 25Ah to 500Ah.
The device has an input for an optional 10kNTC (Murata NPSD0XH103FEB0 or equivalent) used to sense the battery
ambient temperature.
When using the temperature sensor the battery can be recharged in a more accurate way since the device regulates its
charging voltage according to the battery ambient temperature.
L Respect the battery polarity! The device is NOT protected against battery polarity reversal. A connection with
wrong battery polarity will damage the device and generate a fire hazard.
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5.3.6 Output current remote measurement
Figure 12 0…10V output for SMPS output current remote measure connection
Figure 13 4…20mA output for SMPS output current remote measure connection
The NPS2400 provides 2 different outputs for the remote measurement of the current delivered by the device.
The 2 outputs follow 2 major industry standards levels:
0…10V voltage output: 0V corresponds to 0A output, 10V corresponds to the rated output current of the SMPS
4…20mA current output: 4mA corresponds to 0A output, 20mA corresponds to the rated output current of the SMPS
Note: The 2 outputs are floating with respect to the SMPS output (opto-isolated), but their ground is common to GND AUX.
Take care of ground loops when using the remote current measurement in conjunction with the 12 V auxiliary output.
L Respect the connection polarity!
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5.3.7 Remote shutdown input
Figure 14 Remote shutdown input connection with external signal
Figure 15 Remote shutdown input connection by using the AUX power supply
The device includes an opto-isolated input used to remotely shutdown or enabling the device output without the need for
disconnecting the mains input. This input can be used in 2 ways:
a) External signal: when applying an external DC voltage as shown on Figure 14 from 5VDC to 24VDC to the
SHUTDOWN inputs the NPS2400 output will be turned ON or OFF depending on the programmed shutdown polarity
(see §7.4.9).
b) External switch or relay contact: by connecting an external switch or relay contact as indicated in Figure 15 the
NPS2400 output can be switched ON or OFF by only acting on the switch or relay contact.
5.3.8 Auxiliary 12V/100mA output
The NPS2400 provides an auxiliary power supply rated 12V/100mA (max.). This supply is available on the +12V AUX/ GND
AUX terminals of the auxiliary connector. The auxiliary supply is floating (isolated) with respect to the SMPS output. Take care
when using the 12V auxiliary output in conjunction with remote output current measurement to avoid ground loops.
The 12V auxiliary output is short circuit protected by an active circuit.
5.3.9 Auxiliary relay dry contacts
NPS2400 provides an SPDT relay with normally open (NO) and normally closed (NC) dry contacts. They normally indicate that
the output voltage is present and regulated (DCOK). Other functions are available for the relay, see chapter 7.4.16, 7.4.17,
7.4.18 and 7.4.19 for details. When the device is operating in battery charger mode (only on “-24” and “-48” models) the relay is
excited when the battery charging process is terminated, overriding all the other functions.
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5.3.10 Connection to a PC through the USB communication box NPS2400_CB
Figure 16 Connection of the USB communication box (optional)
The NPS2400 is provided with a connector called communication interface where the USB communication box NPS2400_CB
(optional) must be connected. This allows interacting with the device using a PC provided with USB interface and a specific PC
application (“POWER MASTER”) optionally provided.
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5.4 Maintenance
The FAN should be checked periodically (recommended: every 6 moths). Dirty fans can be cleaned using compressed air
generated by a vacuum cleaner from outside of the unit. Do not use high pressure air flux, it can damage the unit.
Optionally a maintenance reminder can be activated by factory (see §7.6.20). The reminder will be activated after a user
definable hours of operation. To acknowledge the reminder the user must keep the button up and the button down pressed for
more then 3 second.
6 Operating modes
NPS2400 power supply has 3 different operating modes, user selectable (see §7.4.12).
Overboost (OB)
Constant current limit (CC)
Battery charger (BC- available only on “-24” and “-48” models)
6.1 Overboost mode (default)
NPS2400 in Overboost mode can provide a temporary power boost up to 150% (3600W) of its rated power for a maximum of 5
seconds. This mode is suitable for powering loads with high inrush current such as motors or highly capacitive loads. It also
helps in blowing fuses of failed loads and separate those from other active loads connected in parallel. The output U/I behaviour
in OB mode is presented in Figure 17.
Figure 17 Output voltage vs. current characteristics in Overboost mode
As soon as the output current becomes > Inom a timer is started; when the timer elapses (5 s) the output is shut OFF and kept
OFF for 10 seconds (hiccup cycle – 5 s ON/10 s OFF).
In case of a “dead short circuit” on the output (Uout<0.1*Unom) the maximum current is still limited at 1.5*Inom, but the output
shuts off after about 100 ms entering a hiccup cycle.

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6.2 Constant current limit mode
When operating in constant current limit mode NPS2400 behaves as a constant voltage source or constant current source
depending on the load. CC mode is suitable for powering loads that do not need high peak currents. The output maximum
current can be set between 0.1*Inom and Inom (see §7.4.5). It will never exceed the programmed value independently on the
load behavior.
In case of a “dead short circuit” on the output (Uout<0.1*Unom) Imax is still limited at Inom, but the output shuts OFF after about
100 ms, entering a hiccup cycle.
This mode can be suitable also for powering systems that have a back-up battery in parallel to the load.
The output U/I behavior in CC mode is presented in Figure 18.
Figure 18 Output voltage vs. current characteristics in constant current limit mode

6.3 Battery charger mode (available only on “-24” and “-48” models)
Figure 19 Battery charger charging profile
This operating mode performs lead-acid battery charging. 12V, 24V or 48V batteries from 50Ah to 1000Ah can be charged. 2
charging modes are possible: normal charge and fast charge.
In normal charge mode the charge current is limited to 0.1C (C = battery nominal capacity expressed in Ah) and the charging
time takes approximately 12h. In fast charge mode the charge current is limited to 0.2C and the charging time is approximately
8h.
The charging algorithm is shown in Figure 19. 3 stages are implemented:
1) Constant current charge: during this phase the SMPS operates as a constant current source limited at 0.1C or 0.2C. The
battery voltage progressively increases until it reaches the constant voltage charge value. Stage 2 starts when this voltage is
reached.
2) Constant voltage charge: during this phase the SMPS operates as a constant voltage source limited in current at 0.1C or
0.2C. The output voltage is kept constant at 14.4V for 12V batteries, 28.8V for 24V batteries or 57.6V for 48V batteries. If
the external temperature sensor is used the constant voltage charge voltage is varied based on the battery ambient
temperature (3 mV/°C). During this phase the current sunk by the battery starts to decrease. Stage 2 ends when the current
sunk by the battery becomes lower than 0.03C or after 8 hrs of constant voltage charge. When Phase 2 is finished the DC-
OK LED is ON and the relay is excited, indicating that the charging process is completed.
3) Floating charge: during this phase the SMPS operates as a constant voltage source but the output voltage is decreased to
13.5V for 12V batteries, 27V for 24V batteries or 54V for 48V batteries. If the external temperature sensor is used the
floating charge voltage is varied based on the battery temperature. This phase is used to compensate the battery self
discharge current and to keep the battery at its maximum capacity. The charge ends after Phase 2, Phase 3 can be
extended for an indefinite period of time, to keep the battery charged when not used.
Battery voltage is checked before starting a charge cycle. For batteries that were deep discharged: if the battery voltage is <
8.4V for 12V batteries, < 16.8V for 24V batteries or < 33.6V for 48V batteries the charger tries to revive the battery. During
revive the battery is charged with 0.04C. If after 10 hours the voltage on the battery still too low a battery error is triggered,
otherwise a charging cycle is started (Stage 1).
To exit the error state the user must acknowledge the error using the OK button.
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7 User interface
7.1 Principles of operation
An integrated user interface composed of an LCD (alphanumerical, 2 x 16 characters, with backlight), 2 status LEDs and 4
buttons is present on the NPS2400. Through this interface the user can modify, monitor and control the SMPS behaviour.
The physical layout of the interface is shown in Figure 14.
Figure 20 User interface physical layout
MENU KEY Used to enter and exit various pages in the user menu.
DOWN KEY Scrolls down menus and values.
UP KEY Scrolls up menus and values.
OK KEY Confirms selection
RED
LED ALARM LShows an abnormal condition (either external or internal to the SMPS)
GREEN
LED DC OK / CHARGE
1. in power supply modes: shows that the device is operating correctly and the output voltage is
regulated
2. in battery charger mode: blinks (1Hz) during charging and turns ON when the battery is charged
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