Enermax Galaxy 1000 W Power Supply
By Gabriel Torres on August 21, 2006


Introduction

Galaxy 1000 W is the most high-end power supply from Enermax and one of the most powerful power supplies for desktops and servers available on the market today. It was designed to fit quad-SLI systems and multi-CPU systems, and it is the first power supply compliant with the forthcoming EPS12V 3.0 standard (as this standard is not yet finalized, Enermax is calling it EPS12V 2007). Let’s take an in-depth look at this beast.

Enermax Galaxy 1000 W
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Figure 1: Enermax Galaxy 1000 W.

Enermax Galaxy 1000 W
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Figure 2: Enermax Galaxy 1000 W.

This model is internally called EGA1000EWL, and Enermax also provides an 850 W version of this very same power supply, Galaxy 850 W.

Being a high-end power supply, Galaxy 1000 W features high-efficiency and active PFC. According to Enermax this power supply has an efficiency between 80% and 85% (compare to 50% to 60% on regular power supplies), meaning less power loss – an 85% efficiency means that 85% of the power pulled from the power grid will be converted in power on the power supply outputs and only 15% will be wasted. This translates into less consumption from the power grid (as less power needs to be pulled in order to generate the same amount of power on its outputs), meaning lower electricity bills.

Active PFC (Power Factor Correction), on the other hand, provides a better usage of the power grid and allows this power supply to be comply with the European law, making Enermax able to sell it in that continent (you can read more about PFC on our Power Supply Tutorial). In Figure 1, you can see that this power supply doesn’t have an 110V/220V switch, feature available on power supplies with active PFC.

Also in Figure 1 you can see another very important feature of this power supply, the reset switch of its protection circuit. Its protection circuit also provides a buzzer, meaning that your power supply will make noise when something goes wrong.

Everything on this power supply is superlative, and we are not only talking about its power spec. To start, we were very impressed by its weight: 12 pounds (almost 6 Kg).

As you can see on the above pictures, this power supply is bigger than standard ATX12V power supplies. With a depth of 220 mm (against 140 mm on regular power supplies) you will be able to install it on any case that has a 220 mm clearance between the rear of the case and the first 5.25” bay. As you will probably install this power supply on a high-end PC using a high-end case, you probably won't have any trouble installing this power supply unit.

On the cooling side, this power supply uses two fans: a huge 135 mm fan on the bottom of the power supply, pulling hot air from inside the PC case and an 80 mm fan on the back of the unit pulling this hot air to the outside.

In Figure 2 you can also see that this power supply uses a modular cabling system for the peripheral cables, but some peripheral cables are attached directly to the power supply internal circuit, not using this modular system.

Introduction (Cont’d)

From the power supply comes a lot of cables and connectors: the standard 24-pin ATX12V v2.x motherboard power connector, one EPS12V connector, two ATX12V connectors that can be put together to create a second EPS12V connector on quad-CPU servers, two auxiliary PCI Express power connectors for SLI/CrossFire systems, one cable containing three peripheral power connectors, one cable containing three SATA power connectors and one connector to be attached on the motherboard for you to monitor the speed of the 80 mm power supply fan through your favorite motherboard monitoring program. We show all these connectors in Figure 3.

Enermax Galaxy 1000 W
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Figure 3: Galaxy 1000 W main cables and connectors.

In Figure 4 you have a closer look at the EPS12V connector, on the two ATX12V connectors that can be transformed into a second EPS12V connector for quad-CPU systems, and the fan monitoring connector.

Enermax Galaxy 1000 W
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Figure 4: One EPS12V, two ATX12V (that can transformed into a second EPS12V) and fan monitoring.

One thing that drew our attention was the gauge of the wire used on the motherboard main power cable, 16 AWG instead of 18 AWG as other high-end power supplies we’ve seen to date. Translation: this power supply uses thicker wires on the main motherboard power connector. All other wires used on this power supply are 18 AWG.

The modular system provides more peripheral cables, if you need. Using a modular system is great, as you need only to attach the peripheral cables you will really need, so you won’t have loose cables inside your PC, providing a better inner airflow. Also, if in the future you need different peripheral cables you can get them with the manufacturer instead of having to buy a new power supply just because your unit doesn’t have the cables you need. A plastic sleeving also protects the peripheral cables, helping organizing the cables inside the PC, providing a better inner airflow thus preventing it from overheating due to loose wires and cables blocking the airflow. Enermax also provides a plastic pouch for you to store all peripheral cables that are not in use at the moment.

Enermax Galaxy 1000 W
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Figure 5: Galaxy 1000 W modular cabling system.

Enermax Galaxy 1000 W
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Figure 6: Plastic pouch containing all peripheral cables.

This power supply comes with the following cables for its modular cabling system: two auxiliary PCI Express power cables, for quad-SLI systems; three peripheral power cables, containing three peripheral power connectors each; two peripheral power cables, containing two peripheral power connectors and one floppy disk drive power connector each; four Serial ATA power cables, containing three SATA power connectors each.

Thus the total number of peripheral connectors that come with this power supply is completely insane: there are 16 peripheral power connectors and 15 SATA power connectors.

Also, this power supply provides four auxiliaries PCI Express power connectors, allowing you to assemble a quad-SLI system without using any kind of power adapter, which is great.

We decided to fully disassemble this power supply to take a look inside.

A Look Inside The Galaxy 1000 W

We decided to disassemble this power supply to see what makes it different from other high-end power supplies. Please read our Anatomy of Switching Power Supplies tutorial to understand how a power supply works inside and to compare this power supply to others.

In this page, we will have an overall look, while in the next page we will discuss in details the quality and rating of the components used.

We can point out several differences between this power supply and a low-end (a.k.a. “generic”) one: the construction quality of the printed circuit board (PCB); the use of more components on the transient filtering stage; the active PFC circuitry; the use of a thermal sensor on the power diodes heatsink for controlling the fan speed and for shutting down the power supply in case of overheating; the power rating of all components; the design; etcetera.

In Figure 7 you can have an overall look from inside this power supply.

Enermax Galaxy 1000 W
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Figure 7: Inside Enermax Galaxy 1000 W.

What immediately caught our eye was the use of two transformers, meaning that this power supply has two separated secondary circuits for the main positive voltages (we will discuss this deeply later). This was expected, as it makes more sense to use two transformers than building a power supply with just one big transformer – all other high-end power supplies we’ve seen to date use just one transformer. In Figure 7 you can also see a smaller transformer on the right (under a transparent plastic protection), which is used by the +5VSB circuit – on all power supplies this output is produced by an independent circuitry, so this isn’t something exclusive from Enermax.

Enermax Galaxy 1000 W
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Figure 8: The two main transformers. On regular power supplies only one is used.

Transient Filtering Stage

As we mentioned on other articles, the first place we look when opening a power supply for a hint about its quality, is its filtering stage. On generic power supplies this stage has only one coil, two ceramic capacitors, one or two metalized polyester capacitors and, if we are lucky, one MOV (Metal-Oxide Varistor).

This power supply from Enermax does not use a MOV at all, being the first time we’ve seen a high-end power supply from a respectable manufacturer not using this component, which is a transient suppressor. As a matter of fact, this is the only flaw we could find on this product.

Enermax used “only” two metalized polyester capacitors, two ceramic capacitors and two ferrite coils on this stage.

Enermax Galaxy 1000 W
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Figure 9: Transient filtering stage (part 1).

Enermax Galaxy 1000 W
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Figure 10: Transient filtering stage (part 2).

The other coils you see in Figure 10 are used on the active PFC circuit.

In the next page we will have a more detailed discussion about the components used in the Galaxy 1000 W.

Primary Analysis

We were very curious to check what components were chosen for the power section of this power supply and also how they were set together, i.e., the design used. We were willing to see if the components could really deliver the power announced by Enermax.

From all the specs provided on the databook of each component, we are more interested on the maximum continuous current parameter, given in ampères or amps for short. To find the maximum theoretical power capacity of the component in watts we need just to use the formula P = V x I, where P is power in watts, V is the voltage in volts and I is the current in ampères.

Keep in mind that this doesn’t mean that the power supply will deliver the maximum current rated for each component as the maximum power the power supply can deliver depends on other components used – like the transformer, coils, the PCB layout and the wire gauge – not only on the specs of the main components we are going to analyze.

For a better understanding of what we are talking here, please read our Anatomy of Switching Power Supplies tutorial.

This power supply uses two RS2005G rectifying bridges in parallel in its primary stage. As each bridge can deliver up to 20 A, the primary rectifying bridge of this power supply can deliver up to 40 A. This stage is amazingly overspec'ed: at 115 V this unit would be able to pull up to 4,600 W from the power grid; assuming 80%  efficiency, the bridge would allow this unit to deliver up to 3,680 W without burning this component. Of course we are only talking about this component and the real limit will depend on all other components from the power supply.

Enermax Galaxy 1000 W
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Figure 11: Rectifying bridges used on this power supply.

No less than eight power MOSFET transistors are used on the primary stage of this power supply. Four 24N50 are used on the active PFC circuit, while four 2SK2607 are used on the switching section (9 A in continuous mode each at 25° C).

For a better understanding on the relationship between these transistors, we drew a simplified diagram of this section of Galaxy 1000 W power supply, see Figure 13.

Enermax Galaxy 1000 W
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Figure 12: Simplified diagram of this power supply showing the location of the eight MOSFET transistors.

As you can see in Figure 12 this power supply uses two transformers with separated switching sections and separated outputs. Two transistors drive each transformer. A single-transistor forward configuration is used, with the two transistors connected in parallel in order to double the maximum current each switcher can handle. Each 2SK2607 can drive up to 9 A in continuous mode or 27 A in pulse mode (which is the case, as the PWM circuit that controls the transistors generate a square wave to control them), both numbers at 25° C. Thus each switcher can handle up to 54 A – i.e., up to this current can be delivered to each transformer, so the total amount of current the primary can theoretically deliver to the two transformers is of 108 A – which is a gigantic current amount.

Enermax Galaxy 1000 W
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Figure 13: MOSFET transistors used on this power supply.

Enermax Galaxy 1000 W
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Figure 14: MOSFET transistors used on this power supply.

If you pay close attention on the pictures above you will see that Enermax put small ferrite beads on the terminals of all transistors. This procedure was repeated on all power rectifiers used on the secondary. This beads act like a filter, decreasing the noise that may be produced by the circuit.

The active PFC circuit is controlled by a UCC3817 integrated circuit located on a small printed circuit board shown in Figure 15.

Enermax Galaxy 1000 W
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Figure 15: Active PFC controller.

Secondary Analysis

As you can see in Figure 12 in the previous page, the first transformer drives the +5 V output and the +12 V output used on the cables that are connected on the motherboard (labeled “CPU,” i.e., +12V1 and +12V2 virtual rails), while the second transformer drives the +3.3 V output and the +12 V output used by peripherals (i.e., +12V3, +12V4 and +12V5 rails). Think of this power supply as having two independent power supplies inside.

This is the first time we’ve seen this approach. The main advantage of this achitecture is that the +12 V line connected on the motherboard (i.e., +12V1 and +12V2 rails) is not connected to the +12 V line used for peripherals (i.e., +12V3, +12V4 and +12V5), so any electrical noise produced by peripherals are not replicated to the CPU. The disadvantage is that since the +12 V outputs from each transformer are not connected together you can face a situation where one of the internal power supplies is overloaded while the other is idle, if power isn't very well balanced (we will explain more about this in the next page).

The first +12 V output (+12V1 and +12V2 rails) is produced by two 40CPQ060 Schottky rectifiers connected in parallel, which can also deliver up to 40 A at 120° C each (20 A per internal diode). The maximum theoretical current the +12 V line can deliver is given by the formula I / (1 - D), where D is the duty cycle used and I is the maximum current supported by the rectifying diode (which in this case is made by two 20 A diodes in parallel). Just as an exercise, we can assume a typical duty cycle of 30%. This would give us a maximum theoretical current of 57 A or 684 W for this +12 V output. The maximum current this line can really deliver will depend on other components, in particular the coil used.

The second +12 V output (+12V3, +12V4 and +12V5 rails) is identical and thus offering a maximum theoretical current of 57 A or 684 W. Thus the maximum combined is 1,368 W. But since these two outputs are not connected together they cannot "borrow" power to each other. We will explain more about this in the next page.

The +5 V output is produced by two 40CPQ045 Schottky rectifiers connected in parallel, each one supporting up to 40 A at 120° C (20 A per internal diode). The maximum theoretical current the +5 V line can deliver is given by the formula I / (1 - D), where D is the duty cycle used and I is the maximum current supported by the rectifying diode (which in this case is made by two 20 A diodes in parallel). Just as an exercise, we can assume a typical duty cycle of 30%. This would give us a maximum theoretical current of 57 A or 286 W for the +5 V output. The maximum current this line can really deliver will depend on other components, in particular the coil used.

The +3.3 V output is produced by two more 40CPQ045 Schottky rectifiers connected in parallel. Using the same math this output can deliver up to 57 A or 189 W.

This power supply +5VSB output (a.k.a. “standby power”) is pretty strong as well. As it happens on all ATX power supplies (even on low-end ones), it uses a separated transformer, however on this Enermax unit an F20SC6 Schottky rectifier is used, which can handle up to 20 A (10 A per internal diode).

And the –12 V output is produced by a 7912 voltage regulator, which can handle up to 1.5 A, so this output provides a maximum theoretical power of 18 W.

On the pictures below you can check all the rectifiers used on the two secondary sections of this power supply.

Enermax Galaxy 1000 W
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Figure 16: Secondary rectifiers used on this power supply.

Enermax Galaxy 1000 W
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Figure 17: Secondary rectifiers used on this power supply.

You can see again the small ferrite beads Enermax used on the terminal of all components, acting like a filter and thus decreasing noise.

This power supply has a temperature sensor attached to the heatsink used by the secondary rectifiers, in charge of controlling the fan speed.

Power Distribution

In Figure 18, you can see Galaxy 1000 W label stating all its power specs.

Enermax Galaxy 1000 W
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Figure 18: Power supply label.

As we already explained, this power supply has two separated power supplies inside. The +12V1 and +12V2 rails are connected to the first power supply, while the +12V3, +12V4 and +12V5 rails are connected to the second one.

According to the label the first power supply has a limit of 408 W (34 A) while the second one has a limit of 492 W (41 A). This is funny because internally the two power supplies are completely identical, so they have, in theory, the same limits. These numbers, however, probably express the levels where the power supply protections were configured.

Because the +12 V outputs from the two internal power supplies don't talk to each other, their maximum power cannot be added.

For better power distribution and efficiency the two power supplies should be delivering more or less the same amount of power with the system running. However, unless you have a multiprocessed system this won't happen. Video cards tend to pull more power than CPUs and thus the internal power supply that has the video cards connected to tend to be more loaded than the power supply were the CPUs are connected to.

Unfortunately we don’t have the necessary equipment to make a true power supply review; we would need to create a real 1,000 W load to check if this power supply could deliver its labeled power or not.

Main Specifications

Enermax Galaxy 1000 W power supply specs include:

* Researched at Shopping.com on the day we published this First Look article.

Conclusions

The use of two independent transformers brings advantages and disadvantages. The main advantage is the non-replication of noise and ripple generated at one side to the other side. So if peripherals are generating electrical noise, this noise won't be delivered to the CPU.

On the other hand the maximum power capability from each internal power supply cannot be simply added. You can have a situation where one of the internal power supplies is very loaded while the other power supply isn't delivering a lot of power. This will happen especially if you don't have a multiprocessed system, because nowadays video cards are pulling more power from the power supply than CPUs. 

As for the total power announced by Enermax, one kilowatt, we have great news, even though we didn’t have the necessary equipment to make a true power supply review – we would need to create a real 1,000 W load to check if this power supply could deliver its labeled power or not.

First, the labeled power is rated at 50° C. Why is this important? When the manufacturer doesn’t state the temperature it usually means 25° C. The problem is that when the power supply temperature is increased, its power delivery capability is decreased. This means that a 500 W power supply rated at 25° C won’t be able to deliver 500 W at 50° C – thus this power supply isn’t really a 500 W part, as your power supply will NEVER run at 25° C. Power supplies typically run between 35° C and 40° C. So Enermax is saying that this power supply will deliver 1,000 W even when running hot.

The second thing that is really impressive about this power supply is that all power components can handle much more current/power than stated by Enermax.

Other features from this power supply include high efficiency (meaning a reduction on your electricity bill), active PFC, the use of high-end components, modular cabling system, two fans (with a speed monitoring cable on the smaller fan for you to monitor it using your favorite monitoring program) and several protections. Talking about protections, this unit has a buzzer that will beep if something goes wrong.

With four auxiliary PCI Express power connectors for your quad-SLI system and two EPS12V connectors – supporting up to four CPUs –, you will be able to use this power supply with your very high-end desktop or server.

We were very impressed by the components used inside this power supply, all high-end. From the rectifiers used, we can say that this power supply can probably deliver its rated 1,100 W. Unfortunately we don’t have the necessary equipment to make a true power supply review; we would need to create a real 1,000 W load to check if this power supply could deliver its labeled power or not.

Galaxy 1000 W is a very expensive power supply, though, quoted at USD 360 in the US, three times higher than the average price of good 550 W units. If money isn’t an issue for you this is probably the best high-end power supply money can buy.

However, at least from the theoretical point of view, this power supply should be used only on multiprocessed systems for a better load balancing. If you are running a single CPU with four video cards maybe other 1,000 W products will provide a better power balance (on this example, one of the internal power supplies would be lightly loaded while the other would be heavily loaded).

The only flaw we can say about this product is the absence of a MOV (Metal-Oxide Varistor), which is a transient filter, on its input filter.

Originally at http://www.hardwaresecrets.com/article/Enermax-Galaxy-1000-W-Power-Supply/365


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