PXe-BLS Dual Redundant AC Power Supplies
PXe-BLS-00
PX Electronics PXe-BLS Dual Redundant AC Power Supplies provide continuous AC output for critical equipment using automatic selection between a DC input source and an AC bypass supply.
Designed for telecoms, SCADA, utilities, transport networks, control rooms and other unattended infrastructure, the PXe-BLS helps maintain power to essential AC loads where interruption needs to be kept to a minimum.
Available from 1 to 10kVA, the series combines pure sine-wave inverter output, fast automatic transfer, remote monitoring, alarm contacts and 19-inch rack-mount construction. Different DC input ranges are available to suit common 24V, 48V, 110V and 220V DC systems.
Technical Highlights for Critical AC Power Applications
Dual Input Supply with Fast Automatic Transfer
Uses both a DC input source and an AC bypass supply, automatically transferring between available sources in up to 5ms to help maintain AC output to the connected critical load.
Pure Sine-Wave AC Output
Provides a clean AC output with published total harmonic distortion of 3% or less, suitable for communication, monitoring, control and other sensitive electrical equipment.
Multiple DC Input & AC Output Configurations
Available for nominal 24V, 48V, 110V and 220V DC systems, with 110V or 220V AC output at 50Hz or 60Hz. Available kVA depends on the selected DC input voltage.
Remote Monitoring & Alarm Integration
RS232 and RS485 interfaces support remote operation and monitoring, with Modbus RTU capability and optional TCP/IP or SNMP integration. Dry relay contacts provide remote fault and shutdown indication.
Rack-Mount Construction with Built-In Protection
Designed for 19-inch rack integration in telecoms, control, utility and infrastructure systems, with protection against overload, overtemperature, short circuit, DC input faults, AC input limits and reverse DC polarity.
Product Information
Dual Redundant AC Power Architecture
The PXe-BLS combines a DC-powered inverter and an AC bypass source within one rack-mounted system.
The connected load receives AC power from the selected source. If that source becomes unavailable or moves outside the permitted operating range, the PXe-BLS automatically transfers to the alternative source where it is available.
Two principal operating arrangements can be selected according to the site power philosophy.
DC-Dominant Operation
In DC-dominant mode, the inverter normally supplies the load from the DC input.
The AC bypass supply remains available as the alternative source. If the DC supply becomes abnormal or the inverter cannot maintain normal operation, the system transfers the load to AC bypass.
This arrangement is useful where a secure DC system or battery-backed DC bus is intended to remain the primary source of power.
DC Supply → Inverter → Critical AC Load
AC Bypass → Automatic Transfer → Critical AC Load
AC-Dominant Operation
In AC-dominant mode, the normal AC bypass supply powers the connected load while it remains within the permitted operating range.
If the AC supply becomes abnormal, the PXe-BLS transfers to inverter operation from the DC source.
This arrangement is suitable where the mains or another AC source is normally preferred and the DC system provides backup power.
AC Supply → Bypass → Critical AC Load
DC Supply → Inverter → Automatic Transfer → Critical AC Load
Move the existing “AC power supply mode” and “DC power supply mode” diagrams from the Images tab into this section. They explain the operating architecture and belong with the System Configuration content rather than in a separate image gallery.
Available System Configurations
| Configuration Parameter | Available Arrangement |
|---|---|
| Output Capacity | 1, 2, 3, 4, 5, 6, 8 and 10kVA |
| Nominal DC Input | 24V, 48V, 110V or 220V DC, subject to required kVA |
| AC Bypass | Nominal 110V or 220V AC supply |
| AC Output | Nominal 110V or 220V AC |
| Output Frequency | 50Hz or 60Hz, with synchronisation to the bypass supply during bypass operation |
| Transfer Time | ≤5ms between inverter and bypass operation |
| Waveform | Pure sine wave |
| Installation | 19-inch rack-mount construction |
| Local Monitoring | LCD status, voltage, frequency, output current, temperature and operating condition |
| Remote Interfaces | RS232, RS485, Modbus RTU, dry contacts; TCP/IP and SNMP options |
Selecting the Correct DC Input
The DC input should be selected around the existing site DC bus or battery-backed supply.
Lower DC voltages require substantially higher input current for the same AC output power. This means cable size, protection, terminal rating and allowable voltage drop become increasingly important on higher-power 24V and 48V systems.
For this reason, not every power rating is available with every DC input voltage. PX confirms the required kVA, DC input range and installation arrangement before the final configuration is selected.
AC Bypass Supply
The bypass source provides the alternative AC path when required by the selected operating mode.
Published bypass input ranges are:
180 to 260V AC for nominal 220V systems
90 to 132V AC for nominal 110V systems
The bypass supply should be correctly rated for the connected load and installation protection arrangement.
Load and Overload Capability
The PXe-BLS is designed for critical electronic and infrastructure loads. The current specification provides:
100 to 120% load for up to 60 seconds
121 to 150% load for up to 10 seconds
Pure sine-wave output
≤3% THD
Published output power factor greater than 0.8
Loads with significant starting current, high crest factor or unusual power-factor characteristics should be reviewed before the unit is selected.
Monitoring, Alarm and Event History
The local display provides operating information including input and output voltage, frequency, output current and temperature.
The system also records alarm events, with the published configuration providing storage for up to 1,000 alarm records. Remote interfaces and dry contacts allow the PXe-BLS to report supply and shutdown conditions to a wider monitoring system.
Configuring a PXe-BLS Dual Redundant AC Power Supply
PXe-BLS units are configured around the available DC supply, AC bypass source, required AC load and site monitoring requirements.
To prepare the correct configuration, PX requires the following information:
| Requirement | Information to Provide |
|---|---|
| Required Output Power | Continuous load in W or VA, plus any short-duration starting or peak requirement. |
| DC Input Supply | Nominal DC voltage, normal operating range and available source current. |
| AC Bypass Supply | Nominal AC voltage and frequency available at the installation. |
| AC Output | Required 110V or 220V AC output and 50Hz or 60Hz operation. |
| Preferred Operating Mode | DC-dominant or AC-dominant operation. |
| Connected Load | Equipment type, continuous power, power factor and any known starting or surge current. |
| Remote Communications | RS232, RS485, Modbus RTU, TCP/IP or SNMP requirement. |
| Alarm Contacts | Required remote fault, shutdown or supply-status indications. |
| Installation | Rack location, available rack space, ventilation and cable-entry requirements. |
| Documentation | Any project-specific test, inspection or compliance documentation required. |
Communication & Monitoring Options
Depending on the required configuration, the PXe-BLS can support:
RS232
RS485
Modbus RTU
TCP/IP
SNMP
Dry relay contacts for remote alarm and shutdown indication
These interfaces allow the BLS to be integrated into SCADA, building-management, telecoms monitoring and other remote infrastructure systems.
Maintenance Bypass
A maintenance bypass arrangement can be specified where the installation requires service access while retaining an available supply path to the connected load.
The required bypass arrangement should be confirmed when the system is ordered so that switching, protection and site operating procedures can be considered together.
Rack Integration
PXe-BLS units use standard 19-inch rack construction, with enclosure height and depth varying according to power rating.
When specifying the installation, allow sufficient space for ventilation, power cabling, DC input conductors, bypass wiring and communication connections.
Output and Connection Requirements
Connection arrangements should be confirmed according to the selected model, DC input current and connected AC load.
Higher-current DC configurations require particular attention to conductor cross-section, cable length, protection and termination resistance. The DC supply should be capable of supporting both normal operation and expected transient demand without excessive voltage drop.
PXe-BLS Series Technical Specification
The PXe-BLS Series is available from 1 to 10 kVA, with DC input voltage and physical format depending on the selected output rating.
| Technical Index (VA) | 1KVA | 2KVA | 3KVA | 4KVA | 5KVA | 6KVA | 8KVA | 10KVA | ||
| Input | ||||||||||
| 22Vdc—28Vdc | Rated Voltage 24Vdc, DC Shutdown Threshold: ≤20Vdc, ≥30Vdc | |||||||||
| 45.5Vdc—57Vdc | Rated Voltage 48Vdc, DC Shutdown Threshold: ≤40Vdc, ≥60Vdc | |||||||||
| 104Vdc—131Vdc | Rated Voltage 110Vdc, DC Shutdown Threshold: ≤90Vdc, ≥135Vdc | |||||||||
| 208Vdc—260Vdc | Rated Voltage 220Vdc, DC Shutdown Threshold: ≤180Vdc, ≥275Vdc | |||||||||
| 24Vdc Input Max Current | 42A/42A | 83A/83A | 125A/125A | X | X | X | X | X | ||
| 48Vdc Input Max Current | 21A/21A | 42A/42A | 63A/63A | 83A/83A | 104A/104A | 125A/125A | 167A/X | 208A/X | ||
| 110Vdc Input Max Current | 9A/9A | 18A/18A | 27A/27A | 36A/36A | 45A/45A | 55A/55A | 72A/X | 90A/X | ||
| 220Vdc Input Max Current | 4.5A/4.5A | 9A/9A | 13.5A/13.5A | 18A/18A | 22.5A/22.5A | 27A/27A | 36A/X | 45A/X | ||
| Bypass | Voltage Range | 180Vac~260VAC/90Vac~132Vac | ||||||||
| Bypass | Current | 4.5A/8.3A | 9.1A/16.5A | 13.6A/26A | 18.2A/33A | 22.7A/41A | 27.2A/50A | 36.3A/X | 45.4A/X | |
| Bypass | Bypass Transfer Time | ≤5ms | ||||||||
| Frequency | 50/60Hz | |||||||||
| AC Output | ||||||||||
| Output Capacity(VA) | 1KVA | 2KVA | 3KVA | 4KVA | 5KVA | 6KVA | 8KVA | 10KVA | ||
| Rated Output Power(W) | 0.8KW | 1.6KW | 2.4KW | 3.2KW | 4KW | 4.8KW | 6.4KW | 8KW | ||
| Rated Output Current | 3.6A | 7.3A | 11A | 14.5A | 18.2A | 21.8A | 29A | 36.3A | ||
| Output Voltage | 220Vac(±10V)/110V(±5V), Adjustable LCD display | |||||||||
| Output Voltage Precision（V） | 220V±1.5%/110V±1.5% | |||||||||
| Power Factor | ＞0.8 | |||||||||
| Inverter Efficiency（80%） | ≥85%（80% linear Load） | |||||||||
| Over Load | 100%-120% 60s, 121%-150% 10s | |||||||||
| Dynamic Response Time | Dynamic Response Time: < 5% Vnom for load change 0% to 100%, transient time < 5ms | |||||||||
| Waveform | Pure Sine Wave | |||||||||
| Bypass Switch Time | ≤5ms | |||||||||
| Output Frequency Precision | 50Hz/60Hz | |||||||||
| Output Frequency | 50-60Hz (auto sync with bypass input) | |||||||||
| THD | ≤3% | |||||||||
| Indication | ||||||||||
| LCD Display | Input and Output Voltage, Frequency, Output Current, Temperature, Percentage, LOGO etc. | |||||||||
| Inverter Status | Normal Mains, Normal Inversion, Battery, Under-Voltage and Output Overload | |||||||||
| Compliance | ||||||||||
| LVD | EN 60950-1 | |||||||||
| EMC/EMI | EN 61000-6-3; EN 61000-6-1; IEC 61000-6-2 and IEC 61000-6-4 | |||||||||
| Cooling | ||||||||||
| Temperature Control | 2 Fans | 4 Fans | 6 Fans | 4 Fans | ||||||
| Colour | ||||||||||
| Colour | Black/Customisable | |||||||||
| Dimensions | ||||||||||
| Dimensions | 482mm/347mm/88mm W/D/H 2U | 482mm/430mm/88mm W/D/H 2U | 482mm/470mm/176mm 4U | |||||||
| Protection | ||||||||||
| Internal Protection | Overload Protection, Over temperature protection, Short circuit protection, Input AC voltage limit protection, Reverse polarity on DC input side | |||||||||
| Input DC Voltage Alarm | Battery Under-Voltage | |||||||||
| LCD Audible and Visual Alarm | Red LED light and audible alarm | |||||||||
| Temperature | Temperature Control Fan | |||||||||
| Alarm Record | Standard is 1000 events (alarms), minimum is 100 | |||||||||
| Interface | ||||||||||
| 5 Dry Relay Contacts | For remote indication of alarm/shut down conditions | |||||||||
| RS232& RS485 | Both available, for remote operation and monitoring | |||||||||
| Option | SNMP, TCP/IP | |||||||||
| Dielectric Strength | ||||||||||
| Between Output and Input | 3500Vdc/10mA/1min. No flashover, no breakdown | |||||||||
| Between input and chassis | 3500Vdc/10mA/1min. No flashover, no breakdown | |||||||||
| Between Output and Chassis | 750Vdc/10mA/1min. No flashover, no breakdown | |||||||||
| Dielectric Strength | 1500Vac. 1 minute (Input and output) | |||||||||
| Working Environment | ||||||||||
| Noise (1m) | ≤40dB | |||||||||
| Operating Temperature | -20℃~+50℃ | |||||||||
| Humidity | 0~90%, No moisture condensation | |||||||||
| Operating Altitude (m) | Altitude Full power up to 2000m. Derating -2% / 100m, max altitude 5000m | |||||||||
Yes.
RS232 and RS485 are available for remote operation and monitoring, with Modbus RTU support. TCP/IP and SNMP are available as communication options, and dry relay contacts provide remote alarm and shutdown indication.
Yes.
The PXe-BLS provides a pure sine-wave AC output with published total harmonic distortion of 3% or less, making it suitable for sensitive communication, monitoring and control equipment.
The system monitors the available DC and AC sources and supplies the load from the selected operating path.
If the active source becomes abnormal, the BLS transfers to the alternative source where it is available. The published transfer time is 5ms or less.
es.
Maintenance bypass functionality can support service access while retaining an available supply path to the connected load.
The exact bypass arrangement should be confirmed for the selected installation and operating procedure.
PX will normally require the continuous AC load, starting or peak demand, nominal DC supply and operating range, available AC bypass voltage, required output voltage and frequency, preferred operating mode, communication requirements and rack-installation details.
For higher-current DC systems, cable length, conductor size and the available DC source current should also be confirmed.
A dual redundant AC power supply provides a critical AC load with access to two independent source paths.
The PXe-BLS uses a DC-powered inverter together with an AC bypass supply and can automatically transfer between them when the selected source becomes abnormal.
In DC-dominant mode, the inverter normally powers the load from the DC source, and the AC supply acts as a bypass.
In AC-dominant mode, the AC bypass normally powers the load and the inverter provides the alternative supply from the DC source.
The preferred arrangement depends on the site’s normal power architecture.
The PXe-BLS is used where communication, monitoring, control or infrastructure equipment requires a dependable AC supply and more than one available power source.
Typical applications include telecoms, SCADA, utilities, railway systems, control rooms, emergency communications and remote infrastructure.
The PXe-BLS includes protection for overload, overtemperature, short circuit, DC input voltage conditions, AC input voltage limits and reverse polarity at the DC input.
Local audible and visual alarms provide additional fault indication.
PXe-BLS configurations are available around nominal 24V, 48V, 110V and 220V DC systems.
The available power rating depends on the selected DC voltage because lower-voltage systems require substantially higher DC current.
