Power Supplies Selection Guide
Power supplies come as DIN rail, perforated, terminal-connector and Modicon ABL types; output voltage and mounting style are the first criteria.
This guide covers the points to look at when choosing products in the Power Supplies category.
Power supply types
- DIN rail power supplies: models mounted on a 35 mm DIN rail (IEC 60715); the first group to look at for 24 V DC control supply in automation panels.
- Perforated type power supplies: Isıso and Hvele models with a metal case, attached to a mounting surface with screws.
- Power supplies with terminal connectors: the panel-mounted Delta Electronics PMT series, in which the wires are connected to a terminal block on the housing.
- Listed directly in this category: single-phase and three-phase power supplies of the Schneider Electric Modicon ABL series, along with buffer and redundancy modules.
What to look at when choosing a power supply
- Output voltage: it must be the same as the rated voltage of the devices to be supplied. On many models the output can be adjusted within a narrow range; the range is given in the product data as "output voltage adjustment range".
- Power and output current: power is the product of output voltage and current (P = U × I); the same wattage means higher current at lower voltage. Add up the continuous currents of the loads; taking into account the inrush current of coils, DC motors and devices with a capacitor on their input that switch on at the same time, choose a rated current above this total. To find the current from the total DC power, you can use the DC option in the Current and Fuse Calculation from Active Power tool.
- Overload behavior: when the output is overloaded, some models keep running by limiting the current, while others cut the output and retry at intervals (hiccup). In the product data of ABB CP models, this information is given in the "characteristic of output" row. For loads with a high inrush current, check the manufacturer's data to see which behavior applies.
- Input voltage and phase: in the product data you will see single-phase models with a wide range such as 85-264 V AC and with a 200-240 V AC input. If the supply will be taken from three phases, look at the models with a three-phase input: Schneider Electric ABLU3A, ABB CP-T and some Isıso models. On models where the input range is selected with a switch on the housing, check the switch position before energizing.
- Regulation and ripple: the output ripple (mVp-p) and the line and load regulation (%) show how stable the output stays. If analog measurement circuits or sensitive electronic boards will be supplied, compare these values.
- Mounting and environment: these devices are for use inside panels and equipment; the IP20 rating seen in the product data offers no protection against water. Take the mounting position and the ventilation clearance to be left around the device from the manufacturer's datasheet, and compare the body width with the free space on the rail.
Buffer and redundancy modules
There are two types of auxiliary modules added to the output of a power supply. A buffer module stores the energy it takes from the DC circuit in capacitors and keeps the output up during mains interruptions or voltage dips lasting milliseconds; it contains no battery. A redundancy module connects the outputs of two power supplies to the same load through a diode or MOSFET; in a 1+1 redundant arrangement, when one of the supplies drops out, the load is supplied from the other, and each supply is chosen with enough power to carry the whole load on its own.
The category also lists both modules of the Schneider Electric ABL8 series; verify the module's compatibility with your power supply from the manufacturer's data. For longer interruptions a battery-backed solution is needed; feeding the AC input of the panel through a UPS is one of them.
The difference between an industrial power supply, an LED transformer and a laboratory power supply
All three provide a DC output, but they are designed for different jobs. The devices in this category are fixed supplies that run continuously inside panels and machines. Constant-voltage supplies made for LED strip lines, including slim-case models and protected models such as IP64, are in the LED Power Supplies (Transformers) category. Bench-type test instruments whose voltage and current limit are adjusted from the front panel are listed under Laboratory Power Supplies. Computer case (ATX) power supplies are not part of this category.
Brands in this category
- Isıso: models listed with codes such as IMR, INLP, IDR and IMDR in the DIN rail type, and INES, IS and ILRS in the perforated type; 5 V, 12 V, 24 V and 48 V DC outputs.
- Delta Electronics: DIN rail Lyte 2 (DRL) and Chrome 2 (DRC) models, and the PMT series with terminal connectors.
- Schneider Electric: Modicon ABLM modular, ABLS single-phase, ABLU three-phase and ABL8 universal power supplies.
- ABB: CP-E, CP-D, CP-S.1 and CP-C.1 DIN rail models, and the three-phase CP-T series.
Hvele is listed with metal-case perforated type models, and GMT HPS and Omron S8VK-C with DIN rail models with a 24 V DC output.
Order notes
- Products are sold by the piece.
- Schneider Electric ABL8 universal power supplies and the buffer and redundancy modules are listed as made-to-order; for these products the lead time is confirmed before the order.
- Hvele product names do not state the output voltage; it is understood from the power and current: the 120 W 10 A model has a 12 V output and the 120 W 5 A model a 24 V output. The voltage is at the end of the stock code (as in MS-120-12) and on the product page.
- You can reach a product directly by typing the manufacturer code (such as ABLS1A24100, IMDR-100-12, S8VK-C12024) into the search.
Comparison and selection table
| Selection Criterion | Compact DIN-Rail SMPS (15 W – 120 W) | Heavy-Duty DIN-Rail SMPS (240 W – 960 W) | Enclosed Perforated-Case (Chassis) SMPS |
|---|---|---|---|
| Mounting Style | Snaps directly onto 35 mm DIN rail (TS 35) | Heavy-duty metal housing on 35 mm DIN rail | Screw-mounted directly to backplate or machine chassis |
| AC Input Range | 1-Phase 100–240 V AC universal auto-ranging | 1-Phase 230 V AC or 3-Phase 380–500 V AC input | 1-Phase 220 V AC (some models have 110/220 V switch) |
| DC Output & Protection | 12 V or 24 V DC (0.6 A – 5 A), overload/short-circuit protected | 24 V or 48 V DC (10 A, 20 A, 40 A), PFC & power-boost | 5 V, 12 V, 24 V, 48 V DC (2 A – 40 A) cost-effective series |
| Typical Application | PLC CPUs, HMIs, sensors, relays & compact control boxes | Solenoid valve banks, DC actuators & main automation panels | LED strip/signage power, CCTV cameras & OEM machinery |
Frequently asked questions
How many watts is a 24 V 10 A power supply?
Power is the product of output voltage and output current: 24 V × 10 A = 240 W. A model with a 12 V output and the same 240 W power delivers 20 A; for this reason, make the comparison not only by the wattage but by the current at the voltage you need. Add up the continuous currents of the loads, account separately for loads that draw a brief high current at start-up, and choose the model whose rated current is above this value.
What is the difference between a DIN rail and a perforated type power supply?
The difference is in the mounting style; the operating principle is the same: both are switching AC-DC power supplies. The DIN rail model clips onto the 35 mm DIN rail in the panel and sits in the same row as DIN rail devices such as fuses, relays and PLCs. The ventilated, perforated metal case of the perforated type model is attached with screws to a mounting plate or to the device housing. The free space in the panel and the mounting surface decide the choice.
Can two power supplies be connected in parallel to increase the output current?
Only if the manufacturer allows parallel operation for that model, and in the way it describes. Two supplies whose outputs are connected directly together may not share the load equally; one may reach its current limit while the other is lightly loaded. If a higher current is needed, first look for a single, more powerful model. If the aim is not to increase the current but to keep the supply going when one supply fails, the two supplies are connected through a redundancy module.
Can the output voltage of a power supply be adjusted?
On many models the output voltage can be adjusted within a narrow range around the rated value; in the data of the products in this category the range is given as "output voltage adjustment range", for example 21,6-26,4 V on some 24 V models. The adjustment is meant to compensate for the voltage drop in a long output cable. It cannot be used to switch to a different rated voltage, such as raising the output from 12 V to 24 V; for that, a model of that voltage is chosen.
Can the power supplies in this category be used for LED strips?
Constant-voltage LED strips are supplied by a DC power supply whose voltage matches the strip and whose power covers the total power of the line with some margin; perforated type models are also used for this purpose. If a slim case or a housing protected against dust and water is needed, look at the LED Power Supplies (Transformers) category. In LED panel and spot luminaires that work with a constant-current driver, these power supplies cannot replace the driver.