Hello. i salvage an emi filter circuit with surge supressor from an atx power supply, i want to put them on a plastic enclosure together with the transformer, is it ok to put this emi filter beside the transformer? is it safe to do this and is there any effect both on the emi filter and transformer? i want to add emi filter and voltage suppressor because most of the time there is a sudden shutdown of power and turns back immidiately especially in my place.

 

Toroidal-Transformers produce a very well defined external Magnetic-Field which
should not cause You any problems.
Place the tip of a Screw-Driver near it while it is under a heavy-Load,
this will give You a feel for how strong, and where, the Magnetic-Field is.
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so its safe to setup like what i did in the plastic box?

 

I have no clue of exactly what is inside your Plastic-Box, or the positioning between parts.
But generally-speaking,
it's not a good practice to mount anything very close to the Transformer,
it not only can "inject" 60hz "Hum" or "Buzz" into other Circuits,
but it also may get quite HOT,
which can affect the operation of many other types of parts.

More space is always better, but You probably won't have any problems.

If the Transformer usually gets HOT under normal Loads,
make sure that there is plenty of Air-Flow to keep the HEAT at a reasonable level.

If Your Box will be "closed", You will need to switch to
an Aluminum-Box that can dissipate the HEAT.
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what inside the plastic box is actually the emi filter circuit with volt supressor, and transformer.

 

If the box is made of a thermo-plastic the transformer-generated heat (there will be some) might soften it sufficiently to make the transformer mounting insecure. You don't want a weighty transformer moving around in the box!
A metal box would avoid that risk, but you would then need to take care the transformer mounting bolt didn't create a short-circuit between the box top and bottom.

 

speaking about how the transformer should be mounted, will the rubber pad transfer heat into the steal washer? , and will they provide heatsink for the transformer? is there any more ways to dissipate heat from the transformer?

 

When making things for my personal use I only let line voltage into plastic boxes after I am very careful to make sure that it is highly unlikely that a circuit or load fault could cause the plastic box to melt or worse, catch fire. Testing includes shorting various components to see what happens. Fuses help limit the maximum power in the box and should be included.

The power supplies I have made are in metal boxes. I would not be comfortable with the fire and health hazard of a power supply in a plastic box in my shop.

If the thing you are making is for personal use you probably don't need to have it certified for electromagnetic interference performance, so placement of the filter should not be critical.

 

the transformer and filter will be interfering based on my setup?

 

will the rubber pad transfer heat into the steel washer?

It will, but not very well. The main rôles of the pads seems to be to provide additional electrical insulation and to protect the windings from abrasion.

will they provide heatsink for the transformer?

Who are "they"? It won't be the transformer suppliers. Normally a metal box would act as a heatsink.

 

i mean the rubber and plate washer,

 

The pads and metal washers would provide only a minimal heatsink function, if any. They might actually prevent circulating air from cooling the transformer. Will the transformer be fan-cooled? A sealed plastic box could become quite hot inside.

 

yes there will be a fan, please see my post on the top,i uploaded the images. but somehow, i was planning to put it in a metal casing.

 

After You have obtained an Aluminum-Box,
verify that your Power-Supply operates as expected,
then take everything apart,
then use Fine-Sand-Paper, or Steel-Wool, to scrub the Aluminum clean
in the area where the Transformer will be mounted,
then wash-down the mounting area with "Brake-Clean" or "Electrical-Contact" spray solvent.
You now have less than an hour before the Aluminum starts to form it's normal Oxide-Layer
caused by exposure to the Oxygen in the surrounding Air, so be prepared.
Mix-Up some "J-B-Weld" Epoxy, and glue the transformer to the Box,
then don't touch it for ~24-hours.
This will provide excellent Heat-Sinking for the Transformer,
and a solid, permanent, trouble-free, mounting arrangement.

If You don't do the cleaning and preparation part correctly,
the Transformer may become detached from the Box within a year or two,
then You will have to add a Screw,Nut, Washer combination to hold it down,
but the J-B-Weld will still provide damage-protection to the Windings.
If this happens, add some Heat-Sink-Compound in between the Box and the Transformer.
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The pads and metal washers would provide only a minimal heatsink function, if any. They might actually prevent circulating air from cooling the transformer. Will the transformer be fan-cooled? A sealed plastic box could become quite hot inside.

And yet almost every company selling the toroid transformers give a hard rubber washer with them. The hard rubber doesn't compress and allows air to circulate around the bottom of the transformer.

 

After You have obtained an Aluminum-Box,
verify that your Power-Supply operates as expected,
then take everything apart,
then use Fine-Sand-Paper, or Steel-Wool, to scrub the Aluminum clean
in the area where the Transformer will be mounted,
then wash-down the mounting area with "Brake-Clean" or "Electrical-Contact" spray solvent.
You now have less than an hour before the Aluminum starts to form it's normal Oxide-Layer
caused by exposure to the Oxygen in the surrounding Air, so be prepared.
Mix-Up some "J-B-Weld" Epoxy, and glue the transformer to the Box,
then don't touch it for ~24-hours.
This will provide excellent Heat-Sinking for the Transformer,
and a solid, permanent, trouble-free, mounting arrangement.

If You don't do the cleaning and preparation part correctly,
the Transformer may become detached from the Box within a year or two,
then You will have to add a Screw,Nut, Washer combination to hold it down,
but the J-B-Weld will still provide damage-protection to the Windings.
If this happens, add some Heat-Sink-Compound in between the Box and the Transformer.
.
.
.

the jb weld will provide permanent mounting of the transformer? and i will not be able to unmount it?

 

And yet almost every company selling the toroid transformers give a hard rubber washer with them. The hard rubber doesn't compress and allows air to circulate around the bottom of the transformer.

what do you mean? should the transformer avoid air in the bottom? so the transformer should be fully enclosed or covered?

 

the jb weld will provide permanent mounting of the transformer? and i will not be able to unmount it?

If You don't want it to be permanent,
put a piece of Aluminum-Foil on a flat, hard, surface,
and then J-B-Weld the Transformer to the Aluminum-Foil.
After it hardens, tear-off the excess Aluminum-Foil around the edges.

This will help to protect the Transformer-Windings from damage or abrasion,
and will improve Heat-transfer to the Aluminum-Box at the same time.

You can do this to the top-side of the Transformer too,
if You want to add additional protection for the Windings.

If your Transformer routinely runs very Hot,
you can then add a small piece of Aluminum on the top as well,
instead of using the Rubber and Steel Washers that were supplied with the Transformer.
Aluminum transfers Heat much better than Steel.
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.

 

If You don't want it to be permanent,
put a piece of Aluminum-Foil on a flat, hard, surface,
and then J-B-Weld the Transformer to the Aluminum-Foil.
After it hardens, tear-off the excess Aluminum-Foil around the edges.

This will help to protect the Transformer-Windings from damage or abrasion,
and will improve Heat-transfer to the Aluminum-Box at the same time.

You can do this to the top-side of the Transformer too,
if You want to add additional protection for the Windings.

If your Transformer routinely runs very Hot,
you can then add a small piece of Aluminum on the top as well,
instead of using the Rubber and Steel Washers that were supplied with the Transformer.
Aluminum transfers Heat much better than Steel.
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.
.

i already mounted the transformer before i red your reply, but anyway, take a look at my setup, please refer to the image i uploaded below, the arrows in yellow are tire interior rubber, i shape them and cut, the purple arrow is the metal plate, i will enclose the transformer on a atx power supply casing. should i change the top rubber(behind the metal plate) with the same size on the bottom? any corrections, suggestions, and improvements based on my work? i really appreciate it.

 

what do you mean? should the transformer avoid air in the bottom? so the transformer should be fully enclosed or covered?

No the rubber pads go between the transformer and the case it's mounted in. This allows air to circulate under it. All of this talk of heat sinking is to me a wild idea. No transformer manufacturer even mentions it, you select the transformer for the load and the design of it takes heating into consideration. A toroid transformer is no different than a E-I type when it comes to heat and heat sinking.

"Torodial transformer benefits:

• low profile
• lightweight
• cool running / high efficiency
• due to the core shape - low stray magnetic flux leakage (low EMI)

Supplied with two neoprene rubber insulating pads, one metal centering washer and all mounting hardware (except the 1,500 VA size). "
The above is from Hammond. - https://www.hammfg.com/electronics/transformers/power/1182