FAQ: PULS QT20.241 DIN Rail Power Supply (24 VDC, 480 W, 20 A):

1. What is the QT20.241 and where is it used?

The QT20.241 is a three-phase DIN-rail mounted power supply providing a regulated 24 V DC output at up to 20 A (480 W). It’s designed for industrial control panels, automation systems, PLCs, drives, and other 24 V DC applications.

2. What are the main technical specifications?

Input voltage: AC 380–480 V (±15 %)

Power factor (typical): 0.94

Output voltage: 24–28 V DC (adjustable)

Output current: 20 A at 24 V, 17.5 A at 28 V

Output power: 480 W

Efficiency (typical): 95 %

BonusPower reserves: 50 % for brief overloads

Derating: –12 W/°C above +60 °C

Dimensions (W × H × D): 65 × 124 × 127 mm

Weight: 870 g

Mounting: 35 mm DIN rail with spring-clamp terminals

3. What input protections and recommendations are provided?

Active harmonic correction (PFC) and inrush-current limiting (3 A)

Recommended external fuse: B-6 A or C-3 A on AC input

Overvoltage, short-circuit, and overload protection built-in

4. How does the output performance work?

Nominal output: 24 V DC at 20 A

Adjustable range: 24–28 V DC via onboard trimmer

Peak “BonusPower” allows up to 50 % extra current for short periods

Low ripple and noise: ≤ 100 mV pp

5. How efficient is the unit and does it require derating?

Typical full-load efficiency is 95 %, minimizing heat dissipation. Above +60 °C ambient the unit derates at 12 W per °C.

6. What are the mechanical and mounting details?

The compact housing (65 × 124 × 127 mm, 870 g) clips onto a standard 35 mm DIN rail. Spring-clamp terminals for AC and DC connections eliminate the need for screw tightening. Maintain at least 50 mm clearance above and below for ventilation.

7. What environmental conditions and safety precautions apply?

Operating temperature: –25 °C to +70 °C

Relative humidity: ≤ 90 % (non-condensing)

Do not open or modify the unit; risk of electric shock, fire, or injury

Installation and servicing must be performed only by qualified personnel following the manual’s warnings and local regulations

8. How do I install the QT20.241?

Switch off power and secure against re-energizing.

Clip the power supply onto a 35 mm DIN rail.

Connect AC input to L1–L3 (and N if used) via spring clamps.

Fit recommended external fuse (B-6 A or C-3 A).

Connect DC output to +V and COM terminals.

Power on and confirm the green DC-OK LED illuminates.

9. How can I monitor its status remotely?

The DC-OK signal provides a voltage-free contact to PLC or external monitoring systems. When DC output is within tolerance, DC-OK closes; it opens on undervoltage or fault.

10. How do I adjust the output voltage?

Use a small flat-head screwdriver to turn the onboard potentiometer. Clockwise increases voltage up to 28 V DC; counter-clockwise decreases to 24 V DC. Verify with a calibrated multimeter.

11. What are common troubleshooting steps?

No DC output: check AC fuse, input wiring, and DC-OK LED.

Output voltage too low: ensure trimmer setting and no excessive load.

Overload/overtemperature shutdown: reduce load or improve ventilation.

Phase imbalance or missing phase: verify phase sequence and continuity.

12. What accessories and optional modules exist?

External EMI filters for noise-sensitive installations

Remote on/off modules and analog monitoring cards

DIN-rail distribution headers and end plates

13. What warranty and support are available?

The QT20.241 carries a 12-month manufacturer’s warranty. Technical support, application assistance, and online documentation are available through PULS or distributor as QTE Technologies (qtetech.com/en)

14. Where can I find the datasheet and installation manual?

Datasheet and product details: https://products.pulspower.com/us/qt20-241.html

Installation manual (EN): https://www.manualslib.com/manual/1543477/Puls-Qt20-241.html