How to Save Money When Buying schottky diode bridge rectifier

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justin66

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Bridge rectifiers and wires

« on: January 27, , 10:19:23 pm » Hey guys im curently working on a simple power supply project. Take mot(microwave oven transformer) replace secondary windings put it through bridge rectifiers put some caps and have something like 15-17v unregulated. Purpose is to power car amps for subs. I have super simple logical questions someone could answer

First question whats the minimal capacitance do i need to have a linear output for 600w for entire system but i plan to upgrade so whats the minimal for 1kw or 2kw load?

Second. I will calculate how much i need later but is it better to have two bridge rectifiers rated for 30amps connected in paralel or is it better to have one 60 amp rated BR?

Third i know i have va transformer  but when i rewind it how do i calculate how much power im geting? My target is as of right now to power 600w subs with as little voltage drop as possible. When i wound it with test wire i found an interesting thing the wire in transformer is 1cubic centimeter thik its output is 12.4v ac and almost 17v dc i tried powering subs with somewhere close to 300w rms voltage droped below 11v why? This wire is capable of passing 30amso the bridge rectifier is rated 15 amps but still i dont think it was the problem. Was it? When i upgraded dc wire from BR to thik amp wires voltage raised from 10 to 11.3v and it was no longer issue there. How do i calculate what BR i need and if i need something like 2kw at 16v i guess its no no. Unless i use like 3 MOTs or a big transformer right? But than comes foth question

Forth whats the best way to deliver high power? And i reccon if mot is capable of 600w continueous and subs are not constant power device so sould i put a battery as a buffer? But than its hard coz its not Conventional voltage.

Fifth question why car capacitors are so big if i managed to get 0.3f farads with a bunch of uf caps but its nowhere close the size and also higher voltage where is the catch?

Sixth question what do you guys recommend for powering power car amps from mains?

Ps sorry for the long text

T3sl4co1l

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Re: Bridge rectifiers and wires

« Reply #1 on: January 27, , 10:49:32 pm » At 12V and line frequency, the rule of thumb is something like 2mF per ampere.  So I'd suggest 100mF (= 100,000uF = 0.1F) rated 16 or 25V.  It will probably be a "computer grade" type, costing around $40, if you're shopping for new parts.

Don't use one of those "boost cap" (0.5F +) things, they're gimmicks, they're not rated for this much ripple, and they don't do much even in the best of cases.

Obviously, you need a big rectifier.  A single part is better.  Diodes don't play well together, in parallel.  At this current, you will need a heatsink, too.

#8 AWG wire is good enough for wiring.

MOTs are only good for about 500VA.  They get very hot at higher power levels.  Heck, they get hot enough just sitting there, without any load at all.  The rectifier spends about half that, so don't expect to use an amplifier over 250W or so.

BTW, did you remove the magnetic shunts?  You want to knock those out, otherwise your output voltage will sag a lot.

You'll need several MOTs, and a 240V 15A or larger mains circuit, to run a full 2kW of amplifiers.  You're better off just getting a mains powered amplifier.

Tim Seven Transistor Labs, LLC
Electronic design, from concept to prototype.
Bringing a project to life?  Send me a message!

justin66

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Re: Bridge rectifiers and wires

« Reply #2 on: January 27, , 11:26:16 pm »

At 12V and line frequency, the rule of thumb is something like 2mF per ampere.  So I'd suggest 100mF (= 100,000uF = 0.1F) rated 16 or 25V.  It will probably be a "computer grade" type, costing around $40, if you're shopping for new parts.

Don't use one of those "boost cap" (0.5F +) things, they're gimmicks, they're not rated for this much ripple, and they don't do much even in the best of cases.

Obviously, you need a big rectifier.  A single part is better.  Diodes don't play well together, in parallel.  At this current, you will need a heatsink, too.

#8 AWG wire is good enough for wiring.

MOTs are only good for about 500VA.  They get very hot at higher power levels.  Heck, they get hot enough just sitting there, without any load at all.  The rectifier spends about half that, so don't expect to use an amplifier over 250W or so.

BTW, did you remove the magnetic shunts?  You want to knock those out, otherwise your output voltage will sag a lot.

You'll need several MOTs, and a 240V 15A or larger mains circuit, to run a full 2kW of amplifiers.  You're better off just getting a mains powered amplifier.

Tim

Thanks for your reply. The best BR i can get is v 60A rated. So if i comnect two of them its not gonna be good? Why? Thanks for capacitance info i will try using ten 10mf caps to save money i will use 16v rated is there a way to decrease voltage when i dont use subs and than just kick in full 17v when i use subs and load will drop the voltage? but how about i increase primary windings? By 30turns(currently its turn per volt 220 of them) and also i wanna put two E parts together am i getting at least 600w? If its like 1.1kVA and 800w microwave oven? Also primary windings are 17awg wire.

Currently im using hacked atx psu at 14v and i used full 600w for an hour or so 7ah battery was almost full how? The psu is rated 12v 16A

mariush

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Re: Bridge rectifiers and wires

« Reply #3 on: January 28, , 12:50:55 am » If you have a lot of current, it may make sense to use one of those ideal diode bridge controllers and four mosfets, see for example LT : http://www.linear.com/product/LT

You don't have 0.7-1.1v per diode voltage drop inside the rectifier (or about 2w per amp lost as heat in the bridge rectifier), you only deal with a few mV per mosfet if you choose them right. 

Also seems like the extra couple of volts would reduce the required capacitance for your project

I'm afraid when it comes to microwave transformers customized, i'm clueless. I don't even understand some parts of your message so I'm staying out of that.

ps. I sincerely doubt it's a good idea to use 16v rated capacitors for this project.

Audioguru

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Re: Bridge rectifiers and wires

« Reply #4 on: January 28, , 01:14:26 am » I agree that a microwave oven is made as cheaply as is possible so a W oven uses a transformer that gets hot (hey who cares, it is in an oven) and has its voltage drop a lot when it is loaded with 600W.
I do not know which amplifiers you powered but if they get hot then they are drawing a lot more power from the power supply than their output power to the speakers.

How are you measuring the amplifier output power? Many car amplifiers rated at "600 Whats! (600W)" actually produce only 100 real Watts.

justin66

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Re: Bridge rectifiers and wires

« Reply #5 on: January 28, , 11:17:05 am »

I agree that a microwave oven is made as cheaply as is possible so a W oven uses a transformer that gets hot (hey who cares, it is in an oven) and has its voltage drop a lot when it is loaded with 600W.
I do not know which amplifiers you powered but if they get hot then they are drawing a lot more power from the power supply than their output power to the speakers.

How are you measuring the amplifier output power? Many car amplifiers rated at "600 Whats! (600W)" actually produce only 100 real Watts.

Well its hard to mesure accurately but first of all i read only rms power second i know with inductors like speakers there is box raise also known as increased resistance. I assume im using somewhere arround 300w rms because there is two speakers rated at 150rms each when i power them they get close to full excursion so i assume its give or take 300w out.
My amp has a pretty big radiator and it gets hot to the touch after an hour of playing but o can still hold my hand on it « Last Edit: January 28, , 11:18:40 am by justin66 »

justin66

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Re: Bridge rectifiers and wires

« Reply #6 on: January 28, , 11:36:01 am »

If you have a lot of current, it may make sense to use one of those ideal diode bridge controllers and four mosfets, see for example LT : http://www.linear.com/product/LT

You don't have 0.7-1.1v per diode voltage drop inside the rectifier (or about 2w per amp lost as heat in the bridge rectifier), you only deal with a few mV per mosfet if you choose them right. 

Also seems like the extra couple of volts would reduce the required capacitance for your project

I'm afraid when it comes to microwave transformers customized, i'm clueless. I don't even understand some parts of your message so I'm staying out of that.

ps. I sincerely doubt it's a good idea to use 16v rated capacitors for this project.

Im sorry im not native english speaker

Basic idea is to modify mot and power the amps. I need to figure out the the best cost efficient methood witch will work fine

My supplyer has no lt. It seems like an awesome idea to use mosfets instead of diodes can you suggest some other parts like that i will search for it in www.evita.lt . but how about the waveform of mosfet BR is it going to become squere or not?

How about i increase primary windings to increase the efficiency thats how it works right? There is 17awg or about 1cubic mm wire as primary it is one turn per volt 220turns so if i add a couple of turns for primary i will end up increasing its efficiency or not?

Or how about adding in those separators i will decrease its output and heat as well right?


There is one more idea get an other mot and put two secondaries in series it will be two turns per volt this way efficiency should rise and heat drop. But now i dont have one handy

Yet an other idea is to submerge it in oil « Last Edit: January 28, , 12:57:51 pm by justin66 »

macboy

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Re: Bridge rectifiers and wires

« Reply #7 on: January 28, , 02:30:57 pm »

Thanks for your reply. The best BR i can get is v 60A rated.

Use a lower voltage rectifier. Rectifiers with higher reverse voltage ratings also have a higher forward voltage drop compared to ones that have a lower reverse voltage rating. If you can find a 100 V or even 50 V one, that would be ideal. Or use four separate Schottky rectifiers which have significantly lower forward voltage drop than silicon types. I salvage these from dead SMPS power supplies (like PC supplies). You can find some that will pass tens of Amps with barely 0.3 or 0.4 V drop, but are only rated for 30 or 40 V reverse voltage.  These are used on those supplies for the same reason you want them: lower voltage drop for better efficiency. With low voltage secondaries, you need to save every mV you can.

pmbrunelle

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Re: Bridge rectifiers and wires

« Reply #8 on: January 28, , 05:23:06 pm » Here's another idea...

Use an AC motor (mains powered) to drive an automotive alternator. A belt drive should not be too difficult to figure out.

The power levels here are such that this may actually be reasonable...

T3sl4co1l

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Re: Bridge rectifiers and wires

« Reply #9 on: January 28, , 06:34:08 pm » More primary turns will keep it running cooler.  But then you need more secondary turns, too.

You want the metal spacers (magnetic shunts) out.

Tim Seven Transistor Labs, LLC
Electronic design, from concept to prototype.
Bringing a project to life?  Send me a message!

AG6QR

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Re: Bridge rectifiers and wires

« Reply #10 on: January 29, , 05:28:37 am »

The best BR i can get is v 60A rated. So if i comnect two of them its not gonna be good? Why?

Generally, it's not a good idea to put diodes in parallel.  Putting two bridge rectifiers in parallel is basically just putting four sets of diodes in parallel.

Why not put diodes in parallel?  To a first approximation, it seems like it should work.  The diodes in a parallel pair will have equal voltage across them, therefore equal current, right?  Maybe not.  A problem is that a diode's I-V curve depends on temperature, and if you hold voltage constant, a slight increase in temperature will result in a significant increase in current. 

When you have two diodes in parallel, inevitably one will get just a little bit more current than the other (or one may get a little warmer than the other, which ends up causing the same problem).  The one with more current will then heat up more than the other.  This heating will cause it to grab still more current relative to its neighbor, which will in turn cause more heating, causing more current, etc..  This is a self-reinforcing positive-feedback loop.  It's known as "current hogging".  One diode will normally end up carrying a large majority of the current, while the other diode loafs along, carrying very little.  If the current in the "hogging" diode is more than the rating of the diode, the diode will probably fail open circuit eventually.  That leaves the other diode to suddenly start carrying all the current, and it will then fail.

There are strategies to minimize this. You can put both diodes close together on the same heatsink to keep their temperatures close.  You can put very low value, high power ballast resistors in series with each diode to try and balance out the currents.  But if you can use a single part rated for the full current, that generally works better than trying to split the current between two parts each rated to carry half.

Note that this same effect happens to LEDs, not just rectifier diodes.

Picking the right rectifier module is very important. It helps save energy, prevents system problems, and cuts costs. New technology, like SiC and GaN, makes these modules work better and last longer. Industries like electric cars and green energy use these improvements a lot. Tools like automation and AI make systems even more reliable. They can predict problems and reduce delays. Choosing the right module is key for making systems work well and last a long time.

Key Takeaways

• Picking the right rectifier module saves energy and avoids problems. It also helps lower costs and keeps the system reliable.

• Match the rectifier's voltage and current to your system's needs. This stops overheating and prevents wasting energy.

• Choose modules with high efficiency to save energy. New tech like SiC and GaN can work at over 99% efficiency.

• Keep the module cool to avoid overheating. Good cooling methods help it last longer.

• Make sure the module has safety certifications. This shows it meets quality rules and works well.

Understanding rectifier modules

Definition and function

A rectifier changes alternating current (AC) into direct current (DC). This process, called rectification, is needed for devices that use steady DC power. Rectifier modules use parts like diodes or silicon-controlled rectifiers to do this job well. These modules are found in systems needing reliable power, like factory machines and green energy setups.

Role in power conversion systems

Rectifier modules help deliver smooth and steady power. They adjust voltage and current to fit connected devices. For instance, front-end rectifiers give steady single-output voltages. They also allow features like easy replacement and backup systems. These features are important for wireless networks and energy systems. Picking the right rectifier improves power use, cuts energy waste, and boosts system dependability.

Applications in various industries

Rectifier modules are used in many fields. In data centers, they keep power running with no interruptions. In hospitals, they protect important systems by ensuring constant power. Factories use advanced rectifiers to handle voltage spikes and reduce electrical noise. Rectifiers are also key in electroplating and anodizing, where strong and precise control improves product quality.

Tip: When picking a rectifier module, check its efficiency, strength, and compatibility to match your system’s needs.

Criteria for selecting a rectifier module

Voltage and current requirements

When picking a rectifier module, match its voltage and current to your system. If the module is too small, it can overheat or break. If it's too big, it wastes energy and costs more. For example, single-phase rectifiers handle 0.5 to 3.0 amps. These are good for IT, telecom, and car systems. Three-phase rectifiers handle up to 35 amps or more. They work well for electronics and factories.

Think about whether you need a single-phase or three-phase rectifier. Also, check if it’s low, medium, or high current.

Tip: Always read the rectifier's datasheet to ensure it fits your system's needs.

Efficiency and power loss

Efficiency is very important for a rectifier module. Higher efficiency means less wasted energy and lower costs. New tech like CoolGaN™ and SiC are very efficient. CoolGaN™ can reach over 99% efficiency at half load. This makes it great for high-performance systems.

Check how efficient the rectifier is under different loads. A flat efficiency curve means steady performance. This is useful for systems like telecom networks, where power needs change during the day.

Thermal management

Good thermal management keeps a rectifier module working longer. Heat can harm parts if not controlled. Use cooling methods like vents and airflow to manage heat. In crowded racks, forced-air cooling might be needed.

• Vents and airflow are key for cooling.

• Forced-air cooling helps in tight spaces with poor airflow.

• Check temperatures in different areas to spot hot spots.

Measuring temperatures in your system can find problem areas. Fixing these early stops overheating from causing damage. By managing heat well, you can make your rectifier module last longer and work better.

System compatibility

When picking a rectifier module, make sure it fits your system. If it doesn’t, it might cause problems or even failures. First, check the input and output voltage ranges. These must match your system to avoid power issues. Also, look at the module’s size and connection types. If these don’t fit, installing and maintaining it can be harder.

Think about where your system will be used. For example, if it’s in very hot or wet places, pick a module made for those conditions. Some modules have special coatings or cases to handle tough environments. Lastly, check if the module works with your system’s protocols, like those in telecom or factory setups.

Tip: Always read your system’s manual to know what it needs before buying a rectifier module.

Reliability and durability

A good rectifier module should work well for a long time. Reliable modules reduce downtime and save on repairs. Look for ones with high MTBF ratings. This shows how long they last before breaking. Higher ratings mean fewer problems.

Durability depends on strong materials and design. Good modules handle power surges and voltage changes easily. Industrial modules often have tougher parts for hard conditions. Heat control also matters for durability. Modules with heat sinks or cooling systems last longer.

Note: Spending more on a strong and reliable rectifier module now can save money later by avoiding frequent repairs.

Cost considerations

Cost is important, but it’s not the only thing to think about. Compare prices of modules that meet your needs. Cheaper ones might not be as efficient or long-lasting. Spending more upfront can save money over time.

More people need power electronics now, so better modules are more affordable. Technologies like SiC and GaN are efficient and last longer. They’re great for saving money in the long run. Renewable energy systems also need strong rectifiers. These turn AC from solar panels or wind turbines into steady DC power.

Tip: Think about total costs, like energy savings and repairs, when choosing a rectifier module.

Types of rectifier modules

Diode-based rectifiers

Diode-based rectifiers are simple and very common. They use diodes to change AC power into DC power. These are great for basic tasks without needing advanced controls. You can find them in things like battery chargers and small gadgets.

There are three main kinds of diode-based rectifiers: half-wave, full-wave center-tap, and full-wave bridge. Each type works best for different needs. Half-wave rectifiers use one diode, so they are cheap but less efficient. Full-wave rectifiers, like center-tap or bridge types, use more diodes. This makes them better at giving smooth and efficient DC power.

Tip: If you need better efficiency and smoother power, pick full-wave bridge rectifiers. For cheaper options, half-wave rectifiers work fine.

Thyristor-based rectifiers

Thyristor-based rectifiers are used for high-power jobs. They use thyristors, which handle big currents and voltages. These are common in factories, motor systems, and high-voltage setups.

Thyristor rectifiers give more control over voltage than diode ones. But they are less efficient because of energy loss. They also respond slower to changes in power needs. For example, they can cause harmonic distortion, which might affect sensitive devices.

Note: Thyristor rectifiers are best for systems needing precise voltage control, even if efficiency is lower.

Controlled and uncontrolled rectifiers

Rectifiers can be controlled or uncontrolled. Controlled ones let you adjust voltage and current. These are good for systems needing flexible power. Uncontrolled ones give fixed DC power and are simpler.

Controlled rectifiers often use thyristors or IGBTs to manage power. They are used in motor systems, welding tools, and green energy setups. Uncontrolled rectifiers, usually diode-based, work well for basic tasks like charging batteries.

Tip: Use controlled rectifiers for systems needing precision. For simple tasks, uncontrolled ones are cheaper and easier to use.

Single-phase and three-phase rectifiers

Choosing between single-phase and three-phase rectifiers depends on your system's needs. Single-phase rectifiers are simple and cheaper. They work well for small devices and basic electronics. But their DC output is less stable because of more ripple.

Are you interested in learning more about schottky diode bridge rectifier? Contact us today to secure an expert consultation!

Three-phase rectifiers give smoother and steadier DC power. They have less ripple, which improves voltage quality. These are better for high-power systems like factory machines. Their higher DC output voltage suits demanding setups.

• Advantages of Three-phase Rectifiers:

  • Smoother and steady voltage output.

  • Less ripple for stable DC power.

  • Higher DC output voltage.

  • Better efficiency for big power systems.

For reliable power, pick three-phase rectifiers. For simpler systems, single-phase rectifiers are enough.

Modular and integrated systems

Modular and integrated rectifier systems have different benefits. Modular systems use separate modules you can add or replace. This makes them good for systems needing upgrades or repairs. You can fix or expand without stopping the whole system.

Integrated systems combine parts into one unit. They save space and work well in tight areas. These systems often use advanced designs for better efficiency and reliability.

• Benefits of Modular Systems:

  • Easy to expand for more power.

  • Simple to fix or replace parts.

  • Less downtime during upgrades.

• Advantages of Integrated Systems:

  • Compact for small spaces.

  • High power density and reliability.

  • Efficient with smart designs.

For flexible systems, modular setups are best. For small and efficient systems, integrated ones are ideal.

Evaluating and testing rectifier modules

Reviewing datasheets and specifications

Datasheets are important for checking a rectifier module. They show details about how it works and its features. Look at key specs like voltage range, current capacity, and efficiency. These help you decide if the module fits your system.

Some manufacturers add special features to improve performance. For example, STMicroelectronics makes Schottky diodes with low voltage drop. These are great for fast chargers and electric cars. Diodes Incorporated offers ABS10A bridge rectifiers with glass protection and RoHS compliance. These work well for changing AC to DC power. Vincotech creates compact modules for better cooling and switching.

Tip: Compare datasheets from different brands to find the best option.

Performance testing under load

Testing under load checks if a rectifier module works well in real use. Set up a test that matches the system’s conditions. Change the load to see how it handles different currents and voltages. Watch for stability and efficiency during heavy loads.

Modules like Vincotech’s compact designs perform well under changing loads. They stay steady even when conditions shift. Testing can also show problems like overheating or voltage drops. Fix these issues before using the module.

Note: Use accurate tools to measure voltage and current during tests.

Thermal performance assessment

Managing heat is key to keeping a rectifier module working longer. Check how hot the module gets in different conditions. Use thermal cameras or sensors to find hot spots. Modules with heat sinks or fans handle heat better in tough environments.

For instance, Vincotech’s modules are built for good heat control. This makes them great for demanding tasks. Checking thermal performance helps avoid overheating, which can damage parts and lower efficiency.

Tip: Make sure there’s enough airflow around the module during tests to mimic real conditions.

Compliance with standards

When picking a rectifier module, make sure it follows industry rules. These rules ensure safety, reliability, and system compatibility. Certifications like UL, CE, or ISO show the module is tested for quality. They prove it can handle power loads without overheating or breaking.

Choose modules that meet environmental rules, especially for tough conditions. For example, IP-rated modules block dust and water, making them great for outdoor use. RoHS-compliant modules avoid harmful materials, keeping them eco-friendly.

Tip: Always check the module’s labels or datasheet for certifications. These confirm it meets global safety and quality standards.

Manufacturer and supplier consultation

Talking to manufacturers and suppliers helps you choose wisely. Manufacturers share details about their products, like features and performance. Suppliers can help with pricing, availability, and system compatibility.

Ask manufacturers about their testing methods. Good brands test for durability and efficiency. For example, ask if they check heat control or performance under heavy loads. Suppliers can suggest modules for your industry, like telecom, cars, or green energy.

Make a checklist before talking to them:

• Check the module’s certifications and standards.

• Ask about warranties and customer support.

• Request samples to test in your system.

Note: Working with trusted manufacturers and suppliers gives you better support and access to new technologies.

Picking the right rectifier module is very important. It helps your system work well and saves energy. Matching the module to your system avoids problems and improves performance. High-efficiency modules waste less energy and lower costs. Designs that handle faults make systems more reliable for important tasks.

For instance, small models are easy to maintain and save space. Bigger systems stay cooler and handle faults better. To choose the best module, check its efficiency, strength, and upkeep needs. This ensures your system works well for a long time.

Tip: Buying a good rectifier module now can save money and effort later.

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