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Mean Well KNX-20E-640 KNX Power Supply 640mA 640A

EIB/KNX power supply with integrated chokeno load power consumption < 0.5W

SKU KNX-20E-640

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Overview

KNX-20E-640 is the model of this series: rated current 640mA, rated power 19.2W, typical efficiency 86%.

The KNX Power Supply KNX-20E-640 is a 640mA power supply with high efficiency and a small footprint of only 3SU (52.5 mm).The device has a KNX bus choke output and an additional output for ancillary power.The -30~+70℃ wide temperature operating range can meet all kinds of applications. LED indicators are used in case of normal operation,overload conditions and RESET operation. It is perfectly suitable to power up any products labeled with the KNX trademark. With over 30 years of industrial power supply experience, KNX-20E-640 is engineered to be a reliable and safe solution for KNX bus environment.

Features

EIB / KNX power supply with integrated choke
Compact size with 3SU(52.5mm) width
Safety extra low voltage(SELV)
180~264VAC input
No load power consumption <0.5W
Protections: Short circuit / Overload(short-circuit-proof) / Over voltage
Cooling by free air convection
Isolation classⅠ
LED indicator for normal operation, bus reset and bus overload
Installed on DIN rail TS-35/7.5 or 15
Over voltage category Ⅲ
100% full load burn-in test
3 years warranty

Specifications

KNX-20E-640Specifications from the official datasheet (2025-10-10 edition)

OUTPUT

BUS OUTPUT VOLTAGE WITH CHOKE: Bus,30V (KNX black/red terminal block)
DC OUTPUT VOLTAGE WITHOUT CHOKE: 30V(Additional output for ancillary power)
RATED CURRENT: 640mA
RATED POWER: 19.2W
RIPPLE & NOISE (max.)^Note.2: 100mVp-p
SHORT CIRCUIT CURRENT: 1.4A
SETUP, RISE TIME: 1000ms, 50ms/230VAC at full load
AC MAINS FAILURE BACK-UP TIME(Typ.): 200ms/230VAC at full load

INPUT

VOLTAGE RANGE: 180 ~ 264VAC 230 ~ 370VDC
FREQUENCY RANGE: 47 ~ 63Hz
EFFICIENCY (Typ.)^Note.3: 86%
AC CURRENT (Typ.): 0.22A/230VAC
INRUSH CURRENT (Typ.): COLD START 40A/230VAC
LEAKAGE CURRENT: <1mA / 240VAC

PROTECTION

OVERLOAD: 205 ~ 235% rated output power Protection type : Constant current limiting, recovers automatically after fault condition is removed
OVER VOLTAGE: 33 ~ 35V Protection type : Shut down o/p voltage, re-power on to recover

FUNCTION

RESET: Physical button for reset the bus (Press the RESET button for at least 20 seconds to reset the KNX Bus)
LED DISPLAY: Green LED (ON) :Normal operation Red LED1 (Reset):Reset the bus; Red LED2 ( I >Imax ):Overload/Short
CHOKE: One integrated choke

ENVIRONMENT

WORKING TEMP.: -30 ~ +70℃ (Refer to "Derating Curve")
WORKING HUMIDITY: 20 ~ 95% RH non-condensing
STORAGE TEMP., HUMIDITY: -40 ~ +85℃, 10 ~ 95% RH non-condensing
VIBRATION: 10 ~ 500Hz, 2G 10min./1cycle, 60min. each along X, Y, Z axes
TYPE OF PROTECTION: IP20 design

SAFETY & EMC (Note 4)

OVER VOLTAGE CATEGORY: Ⅲ;According to BS EN/EN61558, BS EN/EN50178,BS EN/EN60664-1, BS EN/EN62477-1; altitude up to 2000 meters
SAFETY STANDARDS: BS EN/EN61558-1,BS EN/EN61558-2-16;BS EN/EN50491-3, EAC TP TC 004 approved
WITHSTAND VOLTAGE: I/P-O/P:4KVAC I/P-FG:2KVAC O/P-FG:0.6KVAC
ISOLATION RESISTANCE: I/P-O/P, I/P-FG:100M Ohms / 500VDC / 25℃/ 70% RH
EMC EMISSION: Compliance to BS EN/EN50491-5-2,-5-3; BS EN/EN61000-3-2,-3-3, EAC TP TC 020
EMC IMMUNITY: Compliance to BS EN/EN50491-5-2,-5-3;BS EN/EN61000-4-2,3,4,5,6,8,11,BS EN/EN55035; heavy industry level,EAC TP TC 020

OTHERS

MTBF: 1899.9K hrs min. Telcordia SR-332 (Bellcore) ; 416.5K hrs min. MIL-HDBK-217F (25℃)
DIMENSION: 52.5*90*54.5mm (W*H*D)
MOUNTING: 35mm mounting rail according to DIN BS EN/EN60715
PACKING: 0.215Kg ; 60pcs/13.9Kg/0.97CUFT

Test conditions and notes5

1. All parameters NOT specially mentioned are measured at 230VAC 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 0.1uf & 47uf parallel capacitor. Measure before Choke.
3. Efficiency before choke.
4. The power supply is considered a component which will be installed into a final equipment. The final equipment must be re-confirmed that it still meets 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)
5. 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).

Technical drawings

KNX-20E-640 Block Diagram — Block Diagram

KNX-20E-640 Derating Curve — Derating Curve

KNX-20E-640 Mechanical Specification — Mechanical Specification

KNX-20E-640 Typical application — Typical application

Typical applications

Downloads

Datasheet1

KNX-20E-640 datasheetKNX-20E-640-SPEC.PDF · 2025-10-10 edition PDF Download

Certificates6

Mean Well 0147476-EAC Certificate PDF Download

Certificate (KNX certificate)(EN) PDF Download

Certificate (KNX-20E-640-TUV)(EN) PDF Download

Certificate (KNX-20E-640-EMC)(EN) PDF Download

Certificate (KNX-20E-640-CE-dec)(EN) PDF Download

Certificate (KNX-20E-640-UK-dec)(EN) PDF Download

Test reports1

Test Report (KNX-20E-640)(EN) PDF Download

Catalogues3

Mean Well Catalog (Industrial) PDF Download

Mean Well DIN RAIL Catalog PDF Download

Mean Well Building Automation Catalog PDF Download

FAQ

Can I use the KNX-20E-640 in a small KNX control panel for building automation?

Yes. This model is a 30V KNX power supply rated at 19.2W with a 640mA output, which fits small KNX building automation panels where a DIN rail form factor is preferred. Its 52.5 × 90 × 54.5 mm (W × H × D) housing also suits compact control cabinets.

Is the KNX-20E-640 suitable for PLC and industrial automation cabinets that include KNX devices?

It is suitable where the cabinet uses a 30V KNX power supply and the required load stays within 19.2W and 640mA. The DIN rail format and 52.5 × 90 × 54.5 mm (W × H × D) size make it practical for slim control cabinet layouts. It is intended as an EIB/KNX power supply with an integrated choke.

Can this power supply be used in a building management enclosure with limited space?

Yes. The KNX-20E-640 is built as a DIN rail power supply and has a relatively narrow 52.5 mm (3 SU) width, which helps in crowded building management enclosures. Its 30V KNX output and integrated choke are aligned with KNX control applications rather than general-purpose cabinet power.

Is the KNX-20E-640 meant for open-air use, or should it stay inside a control cabinet?

This unit is better suited to protected use inside a control cabinet or enclosure. The listed operating temperature is -30°C to +70°C (with derating), and the unit is an IP20 design. For that reason, it should be matched to enclosed indoor control-panel environments rather than exposed locations.

How does the KNX-20E-640 compare with the other Mean Well KNX series power supplies?

On this spec sheet, the KNX-20E-640 and KNX-20U-640 are both 19.2W, 30V, 640mA models with an integrated choke. The difference is the input: the KNX-20E-640 accepts 180 ~ 264VAC or 230 ~ 370VDC, while the KNX-20U-640 is the 115VAC special order model.

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