lc filter for dc motor hum removal

7/25/2019 Lc Filter for Dc Motor Hum Removal

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https://www.youtube.com/watch?v=FG3l29ySCF0&index=66&list=UUgnmHHsB-99_GrbhKDtq3vA

https://www.youtube.com/watch?v=pL0HApSJiAo&index=68&list=UUgnmHHsB-99_GrbhKDtq3vA motor control hum

Removing noise Optimum / Quantum machines with DC motors

(All information is supplied for information, without any responsibility for theresults of its use is accepted)

Introduction.In this thread we will describe one of the ways that you can eliminate the tremendous electrical "noise" produced by DC motors, certain machine tools. This noise is caused by the absence of a filter at the output of the power board, which makes the engine will reach a pulsed power, with peaks of great value, which makes the electric current through the motor windings to induce a pulsating flow inthe motor iron. Being built by this stacked plates, begin to vibrate, producingsound waves in the audible spectrum.

The content of this text is aimed at machines with DC motors up to 500 watts. For example:Millers Quantum BF16 and BF20 Optimum (motors up to 500 watts)Optimum 180 * 300 Vario lathe.

But actually it is valid for any model from another manufacturer, provided thatthe motor is DC, and much power not exceeding the limit indicated.

Beyond remove noise of the machine, the advantages of mounting a filter with aninductor and a capacitor, are: * It reduces harmonics and improves RMS current. * Improves power factor. * Limits the AC component superimposed on the continuous, improving DC motor commutation.

Internal electrical connection of machines.

The feed enters at around through the fuses, and passes through a switch with electrical interlocking (so that if the power goes out, the auto-disconnect). Hence they are the network cables to the small plate. This is a control plate.In the low voltage control plate (type 9V, 5V, etc.) for different uses, such asfeeding the system safety limit switches, or power the tachometer (if winch fitted) are obtained.

Since this control plate, in turn, leaving two network cables, to the power board.That is, the board reach 220V power from the control board.The power board regulates the voltage that reaches it, and becomes continuous adjustable pseudo-effective value, which is what we get to your departure. Hence two wires leave toward the switch.

That pseudo-voltage reaching the switch can be reversed here, so that the motorrotates in one direction or another.

Procedure to remove noise:To eliminate the noise of these machines, it is necessary to mount an LC filterbetween the plate and the switch that feeds the engine, so you have to buy a coil (L) and a capacitor (C) to appropriate values. Also some small mounting hardware, tools, box, etc..


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Justification of the solution. General explanations.An LC filter for continuously rotating machine is not a system to be calculatedaccurately for each case. In fact, there are some values ??that are the best, since low values ??filter bit, but too high values ??distort transients starting,acceleration and deceleration.

The LC filters strict calculation involves much mathematical apparatus. Is fromBode, for underdamped second order system, typical of systems with low resistance, which defines how much is to be the principal harmonic damping, etc..

Anyone who is curious, you can read a brief introduction to the subject here:http://www.fisicarecreativa.com/informes/infor_em/rlc_serie_libre_beck2k2.pdfAs already hinted at in the document mathematical apparatus that accompanies these calculations corresponds to the second cycle of industrial engineering, although the problem itself is simple to solve.

Made these calculations for several machines of this forum, is just adjusted tosuit each case.

When physically mount the LC filter, it is desirable to remember that the capacitors are connected in parallel to add their effects, and if electrolyte, the polarity must be respected, so join the (+) on the one hand, and (-) on the other.

The inductor and capacitor are called "dual component". This means that produce

exactly the same effect, when one is in series and one in parallel. Ie in the LCfilter add their effects.

Another very important function of L is to limit the starting current is required from the power board. Because C is very large, to connect the circuit and be discharged, it behaves like a short circuit, in the sense that they require a lotof power to the power board, to begin charging. This only lasts a moment, because as of to be charged, the current demand will decline, but it is enough to burn the power board time.To avoid this, the coil is mounted in series between the plate and C. As we know, the coils are opposed to abrupt changes of current. Thus, although the C startup requires high current, the coil will not allow this to grow much, leaving this limited form of current that is required to power board. This prevents burning

power thyristors.

Therefore, we should not remove any of the two components.

Details of the LC filter mount.

These schemes are the most important in the whole thread:

Wiring diagrams of the machine, with and without LC filter:

Recommended values ??for the LC filter.We recommend the following values:

* A coil of about 15 milli Henries and 2.5 or 3 Amps maximum current work.* An electrolytic capacitor 1500 micro farads, and 400V maximum voltage.

As we see, we do not provide exact values??, because it is not necessary to restrict both. Yes it is important that their values ??are around which are indicated.


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About the coils:

The coil 15 milli Henries must serially obtained by placing two reels in milli Henries 7 or 8 each, or by purchasing a "choke" phase, and connecting two of thewindings in series.I have chosen to put two coils in series 9 milli Henries. If I see that it takesmore, I can always add another ...In the case of buying a "three-phase choke", the device has three coils with iron cores shared (as in the figure below). The correct connection would be as shown below:

(Due to the type of construction of the core, the three coils share the magneticcore.'s Why not just consider the corresponding terminals, it is necessary to take into account the topology of the iron. With this type of construction, is impossible to achieve all three streams join, so you can only use two coils (any),but never three. With three connected, always have at least one coil whose flowcan see counteracted by the other. the result would much noise vibration platesof the iron core).

Shock phase, connected to filter coil for dc

It is best that the magnetic circuit as short as possible, so that the dispersion is minimal flow by reducing the magnetic reluctance. Thus, the induction and magnetic coupling will be greater. Thus the central coil and any one of the side

is used.

About the condenser to be used:We must also mention that the electrolytic capacitors have polarity, and if youspend your polarity when connected, they explode.Also need a resistor in parallel with it, so that you can download to turn off the machine (if you are way on the other hand ...) Keep in mind that we talk about high voltages, 300-400 volts, and with these capabilities, we can give a big "whiplash".

Acquire the necessary components.An inevitable and sometimes almost insurmountable problem is knowing where to bu

y the necessary electronics.You really can not buy all of them in one store, since the electronic componentsdo not sell as large coils and capacitors, so they have to buy them in a storeof industrial power supplies.Another good option is to buy everything online. It's pretty expensive, but youcan solve everything in one morning .... So many of the options indicated referto shop online Inrtenet rs-call, or RS Components.

Buy the condenser:Electrolytic capacitor 1500 micro farads, and 400Vhttp://es.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=2550046

Buy the coil L:Coil about 15 milli Henries and 2.5 or 3 AmpsServe any of these:

Phase Shock:We can buy this (sometimes it is out of stock):


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# header http://es.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=4576135

Or they (are what I used, they put two in series):Mfr: PR2.5http://www.polylux.com/familia/pr_inductancias_de_linea_monofasicasThere Polilux to call by phone to tell you a dealer in your city. You can also send them an email. Me too I responded to that method.In Madrid the Dimel ordered in, but there are hundreds of distributors throughout Spain. (It took three weeks to get my hands on, because the manufacturer had no stock).

This small company also sells a valid coil. There you telephone them and see howthey order it.Item No.: 002220RI0http://www.tecnotrafo.es/RI-RT-R1.pdf

Plug connectors.(For this, better go to a store electronic components and connectors for microphones questions, asking for three-way connectors, XLR type

Recessed in the box:http://es.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=0405629and this:http://es.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=0405590 (is left)

for around:You can embed a connector as above, or leave it to air.If you leave the air, you will need:A male and a female, type "aero" ie, that are in the air, without embedding.

Terminals for cables of this type (must be the size of the cables used in arrivi

ng at the plate):http://es.rs-online.com/web/search/searchBrowseAction.html?method=browseSubRange&Ne=4294954407&N=4294584945&productNum=6688980

Some points of these:http://es.rs-online.com/web/search/searchBrowseAction.html?method=browseSubRange&Ne=4294954407&N=4294612782&productNum=7187375

Heat-shrinkable tubing of different sizes, and red and black color (very cheap):http://es.rs-online.com/web/search/searchBrowseAction.html?method=browseSubRange&Ne=4294954407&N=4294547605&productNum=2088967

As I say, small is better for mounting buy them in a store, not online, because

they can advise you ....

Mounting the LC filter in the machine.

The way of working is:

Change original fuses, other extra-fast, 5 Amps. This will help protect the machine if something goes wrong.Turn the speed potentiometer to the minimum. In this way, we will work with low


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output voltages, and we will protect us and the power board. To modify the wiring and include the LC filter, change the connections in thefirst plate, and then follow the original cables to the switch.The output cables of the plate are called DC1 and DC2, and those are the ones weneed to change by our filter. You have to do one at a time, that is to say first DC1 change the cable at both ends, and then the DC2.

The time to get down to work, be ever present to you will work with peak voltageup to 400V and current of a few amps (in the extreme case), so you will have tobe very careful. Not a game, you can just use a electric shocks let you trembling all day, and scared to death.Also think it is very easy carry you the power board if conexionas bad things, and the replacement board is worth about 150 euros.

After making the connections, remount everything, and we started the machine.If all went well, the motor begins to rotate smoothly. If we have some bad wiring, not spin, or even be a great short, and some flash connections .... especially if much turn potentiometer, and provoke a sharp rise in the output voltage ofthe plate.In the end, if everything went as it should, I assure you that is very, very good. Not a sound, beyond the spindle bearings. A blast.

And Filter Mounted:

Throughout the time we have been installing different versions of the filter, tosuit the needs of each machine, although essentially the same.

With three phase shock as filter coil.(In the following two pictures there is a small error: They had three windings connected in series, when in fact only connect two.)

With individual coils (Polilux mark).

In the particular case at hand, change the power components,

The procedure is as follows:

Detach the plate and look "very closely" the black surface of each thyristor ordiode. If anyone has a pore is matte blackened, etc.. that will be burned down.

Of the five components, three are diodes, thyristors and two, but outside are equal. They have the same package, and nomenclature vary only in a letter .... Becareful with that. Try to read the nomenclature that burned, not the next.

Power components that can be damaged by an error in assembly.

As the diodes and thyristors are not worth that much, I would buy all five.At present (2010), the Optimum / Quantum manufacturer assembles these components:

Thyristor (2 Eur):http://uk.farnell.com/littelfuse/s6025l/thyristor-25a-600v-to-220/dp/1456980

Diode (2,8 Eur):http://uk.farnell.com/littelfuse/d6025l/diode-rectifier-600v-25a-to220ab/dp/1827589


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The one that almost certainly has not done anything, is the component that is inthe middle of them all. A diode-called "free circulation" which does not belongto the rectifier bridge itself.

More possibilities:If you search the datasheets of these power components you will see that with the same code, changing only one letter, diodes, thyristors and triacs are encapsulated. Thyristors and triacs in this series are complemented, in the sense thatsuch a triac thyristor can replace this range, no problems. The converse is not,of course.

So if you do not find the thyristor, triac you can put that same family:Format triac (two antiparallel thyristors)http://es.farnell.com/jsp/search/productdetail.jsp?sku=1456976

I also wanted to tell you that if a thyristor due to overload burns usually alsoburns a diode, since they work in series, ie pairs.Therefore, it is also possible that a diode is bad, but not something mathematical. Be careful with that.

If it's any consolation, some time ago, in my tests, also burned a bridge of these, and since then I have thyristors and diodes Extra specifically purchased for

leave reserve.

Tip / Trick:When you go to desolder components, Do not risk the board: Cut the legs first ofa sewing kit with scissors to remove the body of the components. So already there just desolder the pins, which are now alone, and you can grab it with tweezers.Thus, the process is very fast unsoldered, which avoid heating the plate tracks,and these become detached from the base bakelite (or fiber, or what it is made). Employs a tinker about 30 watts.if a track comes off, the pineapple is good fat. You can paste, etc.. but the fudge begin to take shape .....

It is true that cutting the legs causes the component unusable, and that one canbe healthy, but you do not really worth it for those prices, carry you to riskthe board itself.

he required equipment consists of:

30W tinker.Tin of good quality.Film desoldering to remove the existing solder tin. It only costs a few euros, and it is necessary not to botch.tweezers to pull the pins on the board, when applying to melt tin tinker.

Repair process.

With the tape desoldering and tinker eliminates all possible tin solder. To putit the end of the ribbon above the weld, and applies the tinner. When the heat tin case, will be absorbed by the film (which is a grid of tin).If done with patience, and giving time to tinker good both hot tape as tin, it will absorb all the tin, and the pins will practically loose.

With the pin cut and the component body already retired, we hold the first leg with tweezers and apply the tinker.


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When the tin is left to melt, the pin is removed by pulling the clips.well with them all.

You can now install the newly purchased component and solder with new tin.

lc filter for dc motor hum removal

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