CLOSER LOOK: Puls CP Series Power Supplies

PULS have been around a long while, 38 years in fact. In that time they have developed a reputation of being a market leader for size, reliability and efficiency. So when we heard that they were updating their popular CP series we were pretty excited – as excited as you can be for a power supply. This series is the most commonly used, based on its super efficiency and small sizing.  We will be specifically road testing the bigger CP20.241 PSU while reviewing the new updated features across the CP range as a whole.

First Impressions

Unboxing the CP20.241 we notice immediately that it’s very well built, it feels sturdy partly thanks to its all-metal enclosure whilst still being relatively light-weight. Puls are well-known for producing compact products and this one is no different.  This particular model has a 20amp output with a width of just 48mm – but still allows room for airflow, but more on that later. The voltage output is adjustable, and there’s a dual output terminal that will accommodate a decent sized electrical screw driver.

Main Features

The CP-series is available in a variety of power combinations and complies with the demands of hazardous locations including Class 1, Div 2, IECEx and ATEX. It supports worldwide AC and DC network supplies with selectable models for 12, 24, 36 and 48VDC systems with current capabilities from 120 to 480watts.

Depending on your preference and industry type, Puls provides you the option of three terminal types including screw type, push in, or spring-clamps for fast installation. If you work in a hazardous environment, you have the option for conformal coated versions which consist of a protective coating on the internal electronic components to protect from moisture, dust, shock and vibration. The medical and railway industries would be well suited with specific type approved versions available to ensure wider tolerances and derating factors.

What we found cool was the new redundancy versions, which integrate a decoupling function based on MOSFET technology. It basically means, that there is no need for additional redundancy modules saving space or spare parts. These are also available in hot-swap connectors to make the change-over process faster.

Road Test

We ran the CP20.241 against three of its high-profile competitors with interesting results. First off, the easy fuse break technology passed, with Puls maintaining minimal inrush current on startup. A reputable 20Amp brand “T” power supply showed a 93.1% efficiency emitting 33 watts of heat. Using the same tests, the CP20.241 got a 95.5% efficiency emitting only 21 watts of heat, saving 12 watts of wasted energy from only 2.5% efficiency difference. This is partly due to a clever internal layout to optimise airflow. The image below shows its internal parts have been strategically placed to allow maximum air flow to run up the entire system. Other comparisons included size and lifespan. On a din-rail, Puls came out the smallest of the three – roughly 30% smaller and a whopping +10.7 years for lifespan comparing to just 4.1 on brand ‘N’. Puls calculate the life-time by measuring the electrolytic capacitors temps against the capacitor manufacture specs. Even the nearest rival was at 6.1. Not bad at all.

Final Verdict

Selecting the right power supply for the right application involves consideration of the input/output parameters, operating environment variables, approvals, and features. Puls design the smallest in the business, but they have also proved they are good at producing great efficiency too. Puls golden rules of a 2% efficiency increase, lowers the thermal design by 10ºC doubling product life-time and doesn’t degrade the lifespan of the surrounding equipment. Puls definitely has the advantage over its competitors on paper delivering new industry benchmarks, but also in testing. Puls provides that reliability that many of us are after, but it also performs extremely well for its size, which is why we happily endorse the CP range of Puls power supplies.