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Mean Well DBUF40-24 Buffer Module Power 24V 40A Supply - DIN Rail

Name: Mean Well DBUF40-24 Buffer Module Power 24V 40A Supply - DIN Rail
Brand: Mean Well
SKU: DBUF40-24
Price: 138.77 USD
Availability: InStock

buffering with capacitorsupport parallel connection to extend buffering time

SKU DBUF40-24

$138.77 USD

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In stock

Overview

The DBUF40-24 buffer module is a supplementary device for regulated DC 24V power supplies. The buffer module utilizes maintenance-free electrolytic capacitors to store energy,thus eliminates the need of periodic replacement as compared to costlier batteries which also have shorter functional life span. The DBUF40-24 comes with comprehensive protection features like over voltage, over current and short circuit protections.Buffer modules can be connected in parallel to increase the output ampacity or the hold-up time.

Features

Buffering with electrolytic capacitors instead of lead acid batteries
Type buffering time of 250ms @22Vdc/40A
Buffer mode selectable by switch:
Fixed mode at 22Vdc
Dynamic mode for Vin-1Vdc
LED indicator for signal status
Supports parallel connection to extend buffering time
Cooling by free air convection
-25~+75℃ wide operating temperature
3 years warranty

Specifications

DBUF40-24Specifications from the official datasheet (2026-03-31 edition)

CHARGING MODE

DC NORMAL OPERATING VOLTAGE: 24Vdc
CHARGING VOLTAGE: 23~30Vdc
CHARGING CURRENT: 900mA Max.
CURRENT CONSUMPTION AT STANDBY: 100mA Max.
CHARGING TIME: 25s Typ. 35s Max.

BUFFER MODE

DC NORMAL OPERATING VOLTAGE: 22Vdc/Vin-1Vdc
DC OPERATING VOLTAGE RANGE: 22-29Vdc
OUTPUT CURRENT(max.): 40A
BUFFER TIME (Refer to Buffering Curve at 22Vdc) Output current 40A: Typ. 250ms Min. 160ms
BUFFER TIME (Refer to Buffering Curve at 22Vdc) Output current 20A: Typ. 500ms Min. 320ms
BUFFER TIME (Refer to Buffering Curve at 22Vdc) Output current 0.1A: Typ. 62s Min. 42s
RIPPLE & NOISE (max.)^Note.2: 350mVp-p

PROTECTION

OVER VOLTAGE: 31~37.5V only,shut down o/p voltage
OVER LOAD: 105%~125% rated output power at buffer mode Protection type:Shut down o/p voltage , re-power on to recover
SHORT CIRCUIT: Protection type:Shut down o/p voltage , re-power on to recover
TVS FOR SIGNALS (max.): 35V
REVERSE POLARITY PROTECTION: By internal MOSFET, no damage , recovers automatically after fault condition removed

FUNCTION

SELECTABLE BY SWITCH Fix 22Vdc(Default): Buffering starts if terminal voltage falls below 22Vdc
SELECTABLE BY SWITCH Vin-1Vdc: Buffering starts if terminal voltage is decreased by > 1Vdc
CONTROL Inhibit (I): +Vs - V(I) < 6Vdc: Buffer module ON; +Vs - V(I) >10Vdc: Buffer module OFF 35Vdc /4mA Max.
SIGNALS Ready(R): Charged ready: V(R)>+Vs - 2Vdc; Unready: V(R)<1Vdc 35Vdc /10mA Max.
SIGNALS Buffering (B): Buffering: V(B)>+Vs - 2Vdc; Other mode: V(B)<1Vdc 35Vdc /10mA Max.
SIGNALS Supply Voltage(+Vs): 10~35Vdc /10mA(Connected to +V or external voltage)
LED STATUS DISPLAY ON: Ready
LED STATUS DISPLAY OFF: Discharged
LED STATUS DISPLAY Flashing 1Hz: Charging
LED STATUS DISPLAY Flashing 10Hz: Buffering
PARALLEL CONNECTION: Refer to Typical Application Notes(Page 6)

ENVIRONMENT

WORKING TEMP.: -25~+75℃(Refer to"Derating Curve")
WORKING HUMIDITY: 5 ~ 95% RH non-condensing
STORAGE TEMP.: -25~+80℃
SHOCK TEST: IEC60068-2-27,30G (300m/S²) for a duration of 18ms,1 time per direction,2 times in total
TEMP. COEFFICIENT: ±0.03%/℃ (0 ~ 75℃)
VIBRATION: Component: 10 ~ 500Hz, 2G 10min./1cycle, 60min. each along X, Y, Z axes; Mounting clip: Compliance to IEC60068-2-6
OPERATING ALTITUDE^Note.3: 5000 meters /OVCⅡ

SAFETY & EMC (Note.4)

SAFETY STANDARDS: IEC62368-1,UL62368-1 approved
WITHSTAND VOLTAGE: IP/OP-FG:2.2KVdc; Signals-FG:2.2KVdc
ISOLATION RESISTANCE: IP/OP-FG, Signals-FG: >100M Ohms / 500Vdc / 25℃/ 70% RH
EMC EMISSION: Parameter Standard Test Level

Conducted BS EN/EN55032 Class B
Radiated BS EN/EN55032 Class B
EMC IMMUNITY: BS EN/EN55035, BS EN/EN61000-6-2

Parameter Standard Test Level

ESD BS EN/EN61000-4-2 Level 4, 15KV air; Level 3, 8KV contact; criteria A
Radiated BS EN/EN61000-4-3 Level 3, 10V/m; criteria A
EFT / Burst BS EN/EN61000-4-4 Level 3, 2KV; criteria A
Surge BS EN/EN61000-4-5 Level 3, 1KV/Line-Line ;Level 3, 2KV/Line-Line-FG ;criteria A
Conducted BS EN/EN61000-4-6 Level 3, 10V; criteria A
Magnetic Field BS EN/EN61000-4-8 Level 4, 30A/m; criteria A

Parameter	Standard	Test Level
Conducted	BS EN/EN55032	Class B
Radiated	BS EN/EN55032	Class B

Parameter	Standard	Test Level
ESD	BS EN/EN61000-4-2	Level 4, 15KV air; Level 3, 8KV contact; criteria A
Radiated	BS EN/EN61000-4-3	Level 3, 10V/m; criteria A
EFT / Burst	BS EN/EN61000-4-4	Level 3, 2KV; criteria A
Surge	BS EN/EN61000-4-5	Level 3, 1KV/Line-Line ;Level 3, 2KV/Line-Line-FG ;criteria A
Conducted	BS EN/EN61000-4-6	Level 3, 10V; criteria A
Magnetic Field	BS EN/EN61000-4-8	Level 4, 30A/m; criteria A

OTHERS

MTBF: 162.6K hrs min. MIL-HDBK-217F (25℃) ; 1420.2K hrs min. Telcordia TR/SR-332 (Bellcore) (25℃) 106.8K hrs min. MIL-HDBK-217F (40℃) ; 717.2K hrs min. Telcordia TR/SR-332 (Bellcore) (40℃)
DIMENSION: 63*125.2*114.9mm (W*H*D)
PACKING: 1.062Kg; 12pcs/12.8Kg/0.74CUFT

Test conditions and notes4

1. All parameters NOT specially mentioned are measured at normal input, rated load and 25℃ of ambient temperature.
2. Ripple & noise are measured at 20MHz of bandwidth by using a 12" twisted pair-wire terminated with a 0.1μF & 47μF parallel capacitor.
3. The ambient temperature derating of 3.5℃/1000m with fanless models and of 5℃/1000m with fan models for operating altitude higher than 2000m(6500ft).
4. The power supply is considered as an independent unit, but the final equipment still need to re-confirm that the whole system complies with the EMC directives. For guidance on how to perform these EMC tests, please refer to “EMI testing of component power supplies.” (as available on https://www.meanwell.com//Upload/PDF/EMI_statement_en.pdf)

Technical drawings

DBUF40-24 Derating Curve — Derating Curve

DBUF40-24 Function Manual — Function Manual

DBUF40-24 Typical Application Notes — Typical Application Notes

DBUF40-24 Mechanical Specification — Mechanical Specification

DBUF40-24 Installation Instruction — Installation Instruction

Typical applications

Industrial control system
Semiconductor fabrication equipment
Factory automation
Electro-mechanical apparatus

Downloads

Certificates5

Mean Well DBUF20-24-DBUF40-24 CB Certificate PDF Download

Mean Well DBUF-20-40 CE-dec Certificate PDF Download

Mean Well DBUF-20-40 UK-dec Certificate PDF Download

Mean Well E183223 UL Certificate PDF Download

Mean Well EAC Certificate PDF Download

Test reports1

Mean Well DBUF40-24 Test Report PDF Download

Catalogues2

Mean Well Catalog (Industrial) PDF Download

Mean Well DIN RAIL Catalog PDF Download

FAQ

What is the Mean Well DBUF40-24 used for?

The DBUF40-24 is a 24V DIN rail buffer module designed to provide short-term hold-up during brief DC power dips or interruptions. It uses maintenance-free electrolytic capacitors rather than batteries, making it suitable for industrial control panels and other 24V DC systems that need short buffering support.

How much buffering performance does the DBUF40-24 provide?

This model is rated for 40A output current and provides a typical buffering time of 250 ms at 22V DC and 40A. It is intended for short-duration ride-through support rather than long backup runtimes.

Does the DBUF40-24 use batteries?

No. The DBUF40-24 uses maintenance-free electrolytic capacitors for buffering instead of batteries. That removes the periodic replacement batteries need and makes it better suited to applications where short-term buffering is the goal.

Can the DBUF40-24 be used in harsh temperature environments?

Yes, this model has a wide operating temperature range of -25°C to +75°C, subject to the output derating curve. That range makes it suitable for many industrial environments where standard commercial-temperature devices may be too limited.

What input and voltage range does the DBUF40-24 support?

The DBUF40-24 is designed for 24V DC systems. Its listed charging voltage range is 23 to 30V DC, and overvoltage protection is specified at 31 to 37.5V with output shutdown protection.

Can buffering time be extended with this model?

Yes. The DBUF40-24 supports parallel connection to extend buffering time. This makes it useful where the standard hold-up performance is not sufficient and a longer short-duration buffer is needed.

What approvals and standards does the DBUF40-24 meet?

This model is approved to IEC62368-1 and UL62368-1 safety standards. It also lists EMC compliance to EN55032 Class B and EN61000-4-2, -3, -4, -5, -6, and -8.

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