AC motor speed controller as a regulated transformer?

[Pexy]

Hy guys. I have been searching for a regulated transformer for quite some time on online sites but they are expencive. So an idea poped into my mind about using an AC motor speed controller as a regulated transformer.
Would it work and if yes do I need to wory about anything in particular?
And if it wouldn't work is there a better solution insted of buying a regulated transformer and is there a site whitch sells them for cheap?
Here's a type ofspeed controller i planed on using (http://m.banggood.com/4000W-220V-AC...lectric-Motor-Speed-Controller-p-1004793.html)

 

[Bluejets]

More detail on what you intend to use it for/with.

 

[Minder]

That appears to be a SCR (probabally Triac) controller intended for a Universal motor, the output will not be a pure sinusoidal, if that is what you are looking for.
You can get the power tool version for around $25-$35.
M.

 

[Pexy]

More detail on what you intend to use it for/with.

I intend to use it as a transformer in a power supply if it were posible

 

[Pexy]

That appears to be a SCR (probabally Triac) controller intended for a Universal motor, the output will not be a pure sinusoidal, if that is what you are looking for.
You can get the power tool version for around $25-$35.
M.

I was going to convert the AC output from that speed controller into dc and use it in a power supply if it is posible

 

[Bluejets]

No...you'll end up killing someone.

 

[Pexy]

No...you'll end up killing someone.

Ok and what if I connected a big risistor in series with speed controller's output to cut down the amperage? Do you have any better ideas because i don't want to spend a lot of money on a regulated transformer

 

[Minder]

You could add a bridge on the output of the triac controller and use a large electrolytic cap for smoothing.
M.

 

[Pexy]

You could add a bridge on the output of the triac controller and use a large electrolytic cap for smoothing.
M.

So i could use that for AC to DC adjustable power supply?

 

[sureshot]

I'm only a hobbyists, and to me it screams dangerous idea, like blujet said. Better off looking for something more suitable.

 

[Pexy]

I'm only a hobbyists, and to me it screams dangerous idea, like blujet said. Better off looking for something more suitable.

Ok, im open for ideas so hit me.

 

[Minder]

Ok, im open for ideas so hit me.

You are not going to find much, that is practical that is, without a transformer, even a Variac is not galvanically isolated.
M.

 

[Pexy]

You are not going to find much, that is practical that is, without a transformer, even a Variac is not galvanically isolated.
M.

What if i got a 220V input and 30V output transformer and a full bridge rectifier an some capacitors to turn the AC output into DC. And would i be able to controll the voltage and curent with some potenciometers? And mybe a mosfet or two?

 

[Minder]

This is exactly what many have done in building a hot wire foam cutter, using a dimmer type (Triac) control in the primary, (I prefer to control the secondary). but whatever works for you.
M.

 

[Bluejets]

Transformer would be ok.
Whether you need a full bridge or not depends on the transformer secondary tappings.
Any connections with the mains should be checked by your local electrician before use and run the gear on a safety switch.
As for control over the voltage, use an adjustable 3 terminal voltage regulator and some caps.
Plenty of circuits around on the web.
You will have to watch your top end voltage as when rectified it may go over the max of some regulators.
24v may be better.
Current regulation using the same regulators in a different arrangement.
Depends though on what levels you need to regulate.
Some of the above boards you can get already made up on Ebay or whatever.
Also do some reading on power supplies and their requirements.

No, a pot will not give you what you want on it's own.

 

[Bluejets]

This is exactly what many have done in building a hot wire foam cutter, using a dimmer type (Triac) control in the primary, (I prefer to control the secondary). but whatever works for you.
M.

I think the op is trending at a bench power supply.
i.e. thyristor clipped mains cable lying around on the bench.

 

[Pexy]

So can you give me like a part list and some guidelines(it does not have to be 2page thing, just some basicks) for the 30V 5A power supply i intend to build

 

[Bluejets]

30v 5A would be costly especially if you build yourself especially the transformer.
One for 30V 150VA would probably be around the Aus$100 plus any handling etc.

Most linear regulators can handle up to 1A (maybe on a heatsink) but you start going higher than that for a simple laypout and you are better off to go with a pre-built switchmode power unit.
Is there an application where you require such high levels.?

An alternative is of course to go to car batteries.
Lithium rechargable another route for high currents but costly also.

Here is an example of a pre-built unit...

http://www.banggood.com/UNI-T-UTP30...onic-xiao-au&gclid=CJHh4qDoicsCFQqBvQodtzcJqQ

 

[Pexy]

OK Thanks Guys. Since i have first got the idea of a homemade bentchtop power supply i thought it was going to be easy and mostly cheap, so i have reconsidered it and chose not to build one or to build one much more weaker one. I am now going to explore pre-build options as Bluejets proposed so if you have any more examples please tell me.
Here are some examples that i found before this. The numbers don't mean anything. I have a price range of about 70 US$ but more expencive are ok too if they are nececery and have all bells and whisels.
1.( http://www.banggood.com/CPS-3205-0-...stable-DC-Power-Supply-110V220V-p-934530.html)
2. (http://www.banggood.com/220V-230V-PS3005-Digital-Adjustable-DC-Power-Supply-p-950926.html)
3. (http://www.aliexpress.com/item/Orig...48&btsid=19b2b047-c088-40f4-a4c0-e85db6718d17)
4. (http://www.aliexpress.com/item/GOPH...48&btsid=203c604c-e642-4016-a664-f866a9a53ce1)
5. (http://www.aliexpress.com/item/New-...48&btsid=15124238-d07f-43c9-a965-ed6f9fe47e02)
6. (http://www.ebay.com/itm/3-Digits-LE...hash=item210764a4cf:m:mbNyy4KS6EdmK5oOoEV2ldg)
7. (http://www.aliexpress.com/item/Orig...48&btsid=19b2b047-c088-40f4-a4c0-e85db6718d17)
8. (http://www.aliexpress.com/item/New-...48&btsid=15124238-d07f-43c9-a965-ed6f9fe47e02)
9. (http://www.aliexpress.com/item/GOPH...48&btsid=203c604c-e642-4016-a664-f866a9a53ce1)
Some of them are pretty similar. Please tell me the ones I should not concider.