9v regulator 110v -> 220v

[nam7340]

Hello all of lego train fans! I just got a quick question on 9v regulator. Can I use 110v 9v regulator with a convertor to 220v 9v regulator? Or should I purchase a new 9v regulator for 220v? Thanks in advance..

Edited April 21, 2014 by nam7340

[1974]

That is just an adapter, not a voltage converter! You can use a step up/down (auto)transformer but they cost as much (or more) than a proper 9VDC psu

[JopieK]

Indeed 220 or 110 V doesn't matter, but the adapter needs to convert it from 220 / 110 V AC to 10V AC (not DC like 1974 says), the regulator itself will convert it from 10V AC to 9V DC.

[1974]

Yeah, 9VAC - sorry

[nam7340]

thank you so much everyone!

[JopieK]

@1974, no it is 10 VAC, that is because of diodes (inside the LEGO regulator unit, that rectify the AC to DC) that cause a power drop of about 1V, so otherwise the actual maximum voltage to the trains would be 8V instead of 9V if one would use a 9V AC adapter!

[Jorrith]

I have a 9V trainset that came without the standard PSU, and uses a cheap PSU with 12V DC output for power. Seems to work just fine.

[1974]

@1974, no it is 10 VAC, that is because of diodes (inside the LEGO regulator unit, that rectify the AC to DC) that cause a power drop of about 1V, so otherwise the actual maximum voltage to the trains would be 8V instead of 9V if one would use a 9V AC adapter!

No, you forgot the squareroot .. It's AC * 1,41 - (0,65+0,65) = DC (in theory only though, 'causeyou'd need an infinitely large capacitor)

So 9VAC would indded work as the LM317 only needs 1,25V above Vout to work

Anyway, the transformer is clearly labeled 10VAC 7VA

[JopieK]

indeed you need to convert it from the wave will also indeed cost some juice, I'm a computer science guy and they tend to be sloppier than electrical engineers with such a things is my experience :)

[Cwetqo]

Here is what is written on adapters.

110V version:

Input: AC120V 60Hz 4,5W

Output: DC12V 200mA

220V version:

Input: AC240V 50Hz

Output: DC10V 7VA

[1974]

I'm a computer science guy and they tend to be sloppier than electrical engineers with such a things is my experience :)

So, much like my sloppy HTML/BASIC coding then

[JopieK]

Haha ;) yups I would prefer at least PHP and/or C(++) or a little Java. Most of the time I work with Arduino / GCC right now and some cocoa for iOS.

But on topic: nam7340: I hope you got the message, it doesn't really matter what adapter you use as long it is around 9V - 12VAC and can draw 200mA or more (more is advised I think).

[1974]

200mA is not really enough

Philo measured the 9V train motor :

http://philohome.com/motors/motorcomp.htm

No load = 80mA

Normal load = 380mA

Stall = 950mA

The original transformer is specced at 10VAC/7VA = 700mA. But that is only in a purely resistive load. With a fullwave capacitor load, like the train speed regulator, a maximum output DC current is about 60%, so there's only 400mA actual juice to the motor

Just about enough to make all the original 9V LEGO trains + cars go nicely on a flat track

With heavier trains, many cars and/or more motors, you need something beefier

[legoman666]

DC wall supplies will work fine in lieu of the AC adapters because rectified DC is just... DC. I had a lot of problems testing my latest loco with 4 motors. I had 3 of the 9v regulators hooked up in parallel and it still wasn't enough. They really are just too weak. I had to switch to a 12v rail off of a PC power supply to get the current I needed.

[nam7340]

Thanks everyone. All of replies helped me a lot. Thanks again!!