PULS QS40.241 Power Supply Practical Guide

PULS QS40.241 Power Supply Practical Guide

QS40.241 Industrial Power Supply: Complete Technical Manual from Installation to Advanced Applications

In industrial automation systems, 24V DC power supply is the "heart" of the control cabinet. A stable, efficient, and sufficiently overloaded power supply directly affects the reliability of all on-site equipment such as PLCs, sensors, relays, solenoid valves, etc. The Dimension series QS40.241 single-phase input power supply launched by PULS, with a peak efficiency of 94.6%, a narrow width of 125mm, a lightweight design of 1.9kg, and a unique BonusPower function, has become an ideal choice for many high demand applications. This article will provide a detailed explanation of the installation specifications, electrical performance, protection mechanisms, parallel/redundant/series configuration methods, pulse load calculation, output circuit breaker matching, and common fault troubleshooting of QS40.241 from a practical engineering perspective, helping electrical engineers and system integrators fully unleash the potential of this power supply.

Overview of Product Core Features

QS40.241 is a 24V output, rated 40A (960W) single-phase DIN rail power supply, with the most outstanding capabilities including:

Ultra wide input range: AC 100-240V (allowing 90-264Vac continuous, 85-90Vac requires derating), suitable for global power grids.

High efficiency and low loss: The 230Vac full load efficiency reaches 94.6%, with minimal self heating, and can operate without derating from -25 ℃ to+60 ℃. Linear derating is required up to+70 ℃ (24W/℃).

BonusPower short-term overload: 1440W (150% rated power) can last for a typical 4 seconds, making it easy to start DC motors, large capacitive loads, or solenoid valves.

High peak current: 110A for 10ms, helping to quickly melt external fuses or trigger magnetic tripping of miniature circuit breakers (MCBs).

Active surge limiting: The input surge current is only 17/11A peak (120/230Vac), much lower than traditional power supplies, to avoid false tripping of higher-level circuit breakers.

Built in data recording: records running hours, temperature peak, input overvoltage events, overheating shutdown times, etc., for easy fault tracing.

Rich control interfaces: DC-OK relay contacts, turn off input, remote adjustment of output voltage (22-28V).

Strict environmental certification: ATEX/IECEx Zone 2 (II 3G Ex ec nC IIC T4 Gc), UL508, DNV/ABS classification society, ISA G3 anti-corrosion level.

This article will provide a set of executable engineering guidelines around these features in the future.

Installation and wiring: the first step to ensure long-term stable operation

2.1 Installation location and environmental requirements

QS40.241 adopts natural convection cooling and must be installed according to the following requirements:

Direction: Standard installation with terminals facing downwards (bottom input/output). If using other directions (such as side mounted or inverted), it is necessary to refer to the derating curve, otherwise it will significantly shorten the life of the electrolytic capacitor.

Gap: Top ≥ 40mm, bottom ≥ 20mm, left and right ≥ 5mm (if adjacent equipment is a heat source, it needs to be ≥ 15mm). If the load remains below 50% for a long time, the gap between the left and right can be reduced to 0.

Environmental temperature: working temperature -25 ℃~+70 ℃. Within the range of+60 ℃ to+70 ℃, a decrease of 24W (i.e. a reduction of 1A in current) is required for every 1 ℃ increase. It is strictly prohibited to turn on electricity in a state of condensation or frost.

Altitude: No need to downgrade below 2000m; Between 2000m and 4000m, a reduction of 60W per 1000m or a decrease of 5 ℃ in ambient temperature is required.

Pollution level: Only applicable to controlled environments with pollution level 2 (no conductive dust).

2.2 Mechanical Installation

Using a 35mm DIN rail (EN 60715, 7.5mm or 15mm high), insert the power supply into the rail and ensure that the bottom hook is securely locked.

Weighing 1.9kg, it is recommended to use rail stops for heavier power supplies to prevent slipping.

If wall installation is required, accessory ZM2.WALL wall bracket can be selected.

2.3 Electrical Wiring (Key Points)

Terminal Function Wire Specification Stripping Length Torque

Input (L, N, PE) AC power supply and protective grounding 0.5-6mm ² solid/0.5-4mm ² multi strand (AWG20-10) 7mm 1 Nm

Output (+/-) 24V DC load 0.5-16mm ² solid/0.5-10mm ² multi strand (AWG22-8) 12mm 2.3 Nm

DC-OK relay voltage free contact 0.15-1.5mm ² (AWG26-14) spring terminal 7mm not applicable

Rules that must be followed:

Using copper wire, minimum temperature resistance: 60 ℃ when the environment is ≤ 45 ℃; 75 ℃ when ≤ 60 ℃; 90 ℃ when ≤ 70 ℃.

PE (protective grounding) must be connected, otherwise the equipment does not meet the requirements of Level I protection.

External disconnect devices (such as circuit breakers or isolating switches) need to be configured on the input side, and ensure that the continuous voltage (L or N pairs of PE) does not exceed 276Vac.

Unused screw terminals must be tightened.

For multi strand wires, it is recommended to use ferrite terminals and ensure that all wire cores are fully inserted into the terminal holes.

2.4 Special Requirements for Explosion proof Zone (ATEX Zone 2)

Only applicable to Class I Division 2 Groups A, B, C, D or II 3G Ex ec nC IIC T4 Gc environments.

It is strictly prohibited to plug or unplug any connectors, adjust voltage, or switch "Parallel/Single" jumpers while powered on.

The final product must provide an IP54 or higher shell and comply with EN 60079-0.

Any replacement of components may compromise the explosion-proof suitability.

Detailed explanation of electrical performance and parameter interpretation

3.1 Input Characteristics

Startup/shutdown voltage: Typical startup voltage is 80Vac, shutdown voltage is 74Vac (hysteresis prevents jitter).

Input current: Typical 4.5A at 230Vac full load. Power factor up to 0.99, current crest factor 1.53, minimal harmonic interference to the power grid.

Start delay: After power on, the output reaches stability within about 800ms, with a rise time of about 15ms and no overshoot (<100mV).

3.2 Output Characteristics

The output voltage of QS40.241 can be adjusted between 24-28Vdc through the multi turn potentiometer on the front panel. The factory setting is 24.1V (full load, chiller, Single Use mode).

Key parameters:

Load adjustment rate: In Single Use mode, the voltage drop from 0A to 40A is ≤ 50mV; in Parallel mode, the drop is about 1000mV (for current sharing).

Ripple noise:<100mVpp (20Hz-20MHz), meeting the requirements of the vast majority of PLCs and sensors.

Output capacitor: Built in approximately 10200 μ F, providing additional transient energy.

3.3 BonusPower and HiccupPLUS modes

This is the most unique feature of QS40.241. When the load exceeds 960W (e.g. 1440W) for a short period of time, the power supply will not immediately turn off, but will continue to provide current (constant current mode) for up to about 4 seconds (typical value). This time is sufficient to initiate most inductive or capacitive loads. If the overload persists after 4 seconds, the output voltage will drop below 20V, and then enter HiccupPLUS mode: the output will be turned off for about 17 seconds, and then automatically restarted to attempt. If the overload is eliminated and restored to normal; If the overload persists, output again for 2-4 seconds and then turn off, repeating this cycle. During the shutdown period, there is still a small voltage and current output (about 0.5W).

Attention: BonusPower is available immediately after each startup or short circuit fault is resolved, without waiting for cooling.

3.4 Peak current capability

In addition to BonusPower (60A lasting for 4 seconds), QS40.241 can also provide a peak current of up to 110A (lasting for 10ms) for:

Quickly trigger the magnetic trip of downstream MCB (see Chapter 5).

Charge loads with large input capacitors, such as drivers and frequency converters.

When the peak of 110A occurs, the output voltage will drop from 24V to about 18.9V (80A/50ms) or even 13.8V (200A/5ms). The DC-OK relay will activate when the voltage drop exceeds 10% and lasts for more than 1ms, which is normal during peak current periods.

Protection functions and safety features

Protection type implementation method parameters

Output overload constant current limit+HiccupPLUS constant current>60A, then burp

Output short circuit with the same average effective current of about 23 A as above

Output overvoltage OVP clamp (typical 30V, maximum 32V) automatically shuts off, requiring power-off reset

Over temperature protection: Internal temperature sensor shuts off output, red light flashes

Input transient MOV varistor absorbs surge

The internal input fuse is built-in and cannot be replaced. The rated value is matched according to the standard

Safe isolation: Double/reinforced insulation is used between input and output, and the output is SELV/PELV (safe extra low voltage), which can be directly touched. But one end of the output (positive or negative) must be connected to the protective ground to comply with PELV requirements.

Leakage current: Typical 0.9mA (TN/TT system) or 2.25mA (IT system) at 230Vac, with maximum values of 1.18mA and 2.82mA, respectively.

Parallel, redundant, and series configurations (common engineering requirements)

5.1 Parallel connection increases output power

Multiple QS40.241s can be connected in parallel to achieve a higher total current (e.g. up to 80A for two parallel connections).

Operation steps:

Place all power sources in "Single Use" mode (with jumper wires not inserted or removed).

Adjust each output voltage to the same value (± 100mV), preferably under the same load conditions.

Insert the "Parallel Use" jumper for all power supplies (switch to parallel mode). This mode will cause the no-load voltage to be about 4% higher than the full load voltage, thereby automatically achieving current sharing.

Simultaneously power on to avoid entering Hiccup PLUS mode for a single device.

The installation gap on both sides should be kept at least 15mm, and it is strictly prohibited to stack them up and down.

Attention: When the number of parallel units exceeds 3, each output needs to be equipped with a 50A or 63A fuse or circuit breaker.

5.2 Redundant Configuration (Improving System Availability)

1+1 redundancy: Two power supplies are connected in parallel, each with 50% load. After one fails, the other bears 100% of the load. For a 40A system, usually two QS40.241s each have 20A, and in the event of a fault, a single unit can output 40A (still within the rated range).

More reliable redundancy solution: Use YR80.242 or YR40.245 redundant modules, with MOSFET decoupling internally, to avoid dragging down the entire bus when one power supply is short circuited internally. Redundant modules also support hot swapping.

Suggestion:

Each power supply uses independent input fuses or independent branches.

Set to 'Parallel Use' mode.

Use the DC-OK relay contacts of each power source for status monitoring.

5.3 Series connection to obtain higher voltage

QS40.241 can be connected in series up to a total output voltage of no more than 150Vdc. Attention: Exceeding 60Vdc no longer belongs to SELV, and an anti electric shock protection cover must be installed, and the output must be grounded. When connecting in series, a gap of 15mm should also be maintained on both sides.

Pulse load calculation: reasonable utilization of BonusPower

Many loads, such as wireless data radios, motor starters, and solenoid valves, have high pulse current characteristics. QS40.241 allows a maximum pulse power of 150% of the rated power (i.e. 1440W). But the following conditions must be met simultaneously, otherwise HiccupPLUS will be triggered:

Pulse power ≤ 1440W.

Pulse duration ≤ allowable BonusPower time (refer to Figure 6-5 in the data manual, which decreases with increasing power).

RMS output current ≤ 40A.

Duty cycle ≤ 0.75.

Actual case: A certain device continuously consumes 480W (50% load) and requires a 1440W pulse every 10 seconds, lasting for 1 second.

From the "Maximum Duty Cycle Curve" graph (Fig.26-2), when Ppeak=150% and P0=50%, the maximum duty cycle is approximately 0.37.

Required duty cycle=1 second/10 seconds=0.1<0.37, therefore feasible.

If the pulse lasts for 3 seconds and the duty cycle is 3/10=0.3, it is still within the range, but the recovery time needs to be checked.

Calculate the necessary pause time: T0=Tpeak × (1/duty cycle -1). When the duty cycle is 0.37, T0=1 × (1/0.37-1) ≈ 1.7 seconds, and there should be margin in the actual design.

Engineers can quickly evaluate using the reference values provided in the table, such as a pulse width of approximately 2.7 seconds at a load of 1440W and a duty cycle of 10%.

Selection and matching of output circuit breakers (MCBs)

In order to quickly cut off the fault in the event of a branch short circuit without affecting other circuits under the same power supply, the downstream MCB must achieve magnetic tripping (usually within 10ms). This requires the power supply to provide a sufficiently large peak current and a sufficiently low line impedance.

QS40.241 can provide a peak value of 110A/10ms, which is sufficient to drive most C-type or B-type miniature circuit breakers. However, limited by the length and cross-sectional area of the wire, the maximum wire length that can guarantee magnetic disengagement is as follows (for example):

Wire diameter C-6A MCB B-10A MCB

1.5mm² 21m 24m

2.5mm² 34m 40m

(The complete table can be found in Table 26-5 of the original text). Attention: The length of the wire needs to be calculated based on the total length of the positive and negative wires (round-trip distance).

If the actual line length on site exceeds the table value, it is necessary to:

Increase the wire diameter.

Use MCB with lower rated current instead.

Install local fuses or electronic fuses at the load end.

Internal data recording: the 'black box' for fault analysis

QS40.241 has a built-in microcontroller that continuously records the following data, which can be read through the PULS service tool even if the device is damaged:

Total operating hours.

The proportion of consumed lifespan (based on temperature and time).

Up to 47 maximum environmental temperature events (with timestamps).

Up to 47 maximum input voltage events.

Input the number and timestamp of overvoltage transients.

The number and timestamp of over temperature shutdown.

Number of power on cycles.

Internal error report.

This is very valuable for analyzing occasional faults on site, such as high-temperature shutdown and input surge damage.

Battery Charging Application

QS40.241 can charge two 12V lead-acid batteries (24V system) connected in series. Please note:

Accurately set the output voltage (no-load, battery terminal measurement) to float charge voltage, for example, 27.5V at 25 ℃, with an increase/decrease of approximately 0.3V every 10 ℃.

Connect a 50A or 63A circuit breaker or isolation diode in series between the power source and battery to prevent reverse discharge.

When the power is turned off, the reverse leakage current is typically 35mA, which may deplete the battery for a long time. It is recommended to use diode isolation.

Common troubleshooting guide

Possible causes and solutions for the fault phenomenon

No output, green LED not on, no voltage at input terminal; Internal fuse blown inspection L/N/PE wiring; Measure input voltage; If the fuse breaks, return to the factory for repair

The red LED is flashing, and there is no output. The input is turned off and activated; Check if the Shut down input terminal is short circuited or if external voltage is applied for over temperature protection; Reduce ambient temperature or improve ventilation

The output voltage drops below 20V and the burping continues to overload for more than BonusPower time, reducing the load; Check if the load is short circuited; Calculate whether the pulse load is compliant

Frequent operation of DC-OK relay results in output fluctuations or temporary drops exceeding 10%. Check if high load startup causes voltage drop; Measure whether the peak current exceeds the capacity

Uneven load during parallel connection, incorrect jumper position; The output voltage is not calibrated and all unit jumpers are confirmed to be in "Parallel Use"; Adjust the no-load voltage to be consistent again

The device is powered on but cannot start. The input voltage is too low (<80Vac). Check the grid voltage; Avoid using input lines that are too long or too thin

Abnormal heating of the shell, high ambient temperature; Insufficient installation clearance; Measure the ambient temperature when the load is too large (2cm below the equipment); Check ventilation; Reduce usage if necessary

Maintenance and life expectancy

QS40.241 has no user repairable parts internally. Its lifespan is mainly limited by electrolytic capacitors. Under 40 ℃ and 40A full load conditions, the calculated lifespan is about 84000 hours (about 9.6 years), while under 25 ℃ and 20A half load conditions, it can exceed 300000 hours. Attention: Electrolytic capacitor manufacturers only guarantee that the parameters will not deteriorate within 15 years (131400 hours), and any values exceeding this limit are theoretical calculations.

Suggest checking every 2-3 years:

Check if the wiring terminals are loose (tighten to the specified torque).

Is the ventilation opening blocked by dust (clean with a soft brush).

Is the ambient temperature still within the allowable range.

If the power supply malfunctions, do not disassemble it yourself and return it to the original factory for repair.