# dc and ac



## bartlettbryce235 (11 mo ago)

Can I run a dc locomotive on a ac power supply?


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## MichaelE (Mar 7, 2018)

For a few seconds...


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## DonR (Oct 18, 2012)

AC current will damage a DC motor. Some DC locos can be
run on a DCC track which uses a modified AC if the
DCC controller has the capability to control the DC loco, but if left
idle the loco motor will be damaged.

Don


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## AmFlyer (Mar 16, 2012)

If you have an AC transformer just get a full wave bridge rectifier. A 5A rated bridge can be had for less than $10. You will also need a way to reverse the engine. An inexpensive DPDT switch will do that.


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## mesenteria (Oct 29, 2015)

bartlettbryce235 said:


> Can I run a dc locomotive on a ac power supply?


Yes, but the voltage must either be rectified by your own rectifier to become DC again, or you must rectify the AC via a decoder installed in the locomotive. However, the decoder needs square wave AC, which the typical DCC system will impart to the rails for you. It happens that the DCC system will also allow you to do all the nifty things decoders can do.

However, yet again, the mere provision of square wave AC by a DCC system won't help your DC locomotive do anything. You'll need a system that allows zero stretching to Address '00', and a throttle that will allow the system to stretch zeroing to generate the motive component of the DCC signal that is DC.

I know, it sounds convoluted, but most of us just stay away from DC ops using DCC. We stick to DC for that. 

And, definitely do not put untreated AC current to the rails and hope your DC motor won't do bad things on you.


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## J.Albert1949 (Feb 3, 2018)

For a beginner, the short answer is, *"no".*
If you have a DC locomotive (is it HO?), you need a DC "power pack" with which to run it.
Trying to run it with AC power will only damage it.

What do you have?
What scale is it?


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## sjm9911 (Dec 20, 2012)

Older lionel stuff ran on both ac and dc, but I never tried it.


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## bartlettbryce235 (11 mo ago)

J.Albert1949 said:


> For a beginner, the short answer is, *"no".*
> If you have a DC locomotive (is it HO?), you need a DC "power pack" with which to run it.
> Trying to run it with AC power will only damage it.
> 
> ...


I have HO scale and I was just wondering because I saw a really good deal on a locomotive but it was dc and I run ac power.


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## DonR (Oct 18, 2012)

Are you running a Euro train system?

Don


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## bartlettbryce235 (11 mo ago)

DonR said:


> Are you running a Euro train system?
> 
> Don


No American


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## DonR (Oct 18, 2012)

This is a bit confusing.
What HO trains are you running on AC?

While some Euro HO trains use AC
most American design HO trains run on DC
or DCC. DCC does put a modified AC
on the track. Is that what you have?

Then too, some time back a member had a toylike train
that was HO and ran on AC as I recall. Is that
what you have? 

Don


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## sjm9911 (Dec 20, 2012)

From there other post don, 








Rivarossi big boy trouble.


why wont the trailing truck on my rivarossi big boy sit level on the track? If there is a way to fix it please let me know at [email protected]




www.modeltrainforum.com


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## bartlettbryce235 (11 mo ago)

This is what I run my layout on.


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## bartlettbryce235 (11 mo ago)

DonR said:


> This is a bit confusing.
> What HO trains are you running on AC?
> 
> While some Euro HO trains use AC
> ...


I posted a picture


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## sjm9911 (Dec 20, 2012)

That's a dc controller!


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## sjm9911 (Dec 20, 2012)

I think these are the directions. But yes, it plugs into ac power and will convert it to dc power. I dont think it outputs any ac. 
https://www.google.com/url?sa=t&sou...sQFnoECAMQAQ&usg=AOvVaw0gQtKtNRFFUh-cxYq3cEHW[/URL]


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## AmFlyer (Mar 16, 2012)

That is a DC power pack. It outputs DC to the track from the variable output.


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## bartlettbryce235 (11 mo ago)

bartlettbryce235 said:


> View attachment 578135
> This is what I run my layout on.


So can I run a dc locomotive from this power source?


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## sjm9911 (Dec 20, 2012)

yup.


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## bartlettbryce235 (11 mo ago)

sjm9911 said:


> yup.


OK thanks.


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## mesenteria (Oct 29, 2015)

😱


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## 65446 (Sep 22, 2018)

sjm9911 said:


> That's a dc controller!


*sjm9911* is correct !
As long as your locos are not AC or DCC, the MRC *IS* an analog *DC* power pack, not AC..
Just remember that if, IF you later on buy *DCC* equipped locos then the Tech II is *not* good for that...


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## Jmstang302 (12 mo ago)

bartlettbryce235 said:


> View attachment 578135
> This is what I run my layout on.


 Use the DC "track" terminals. Don't hook the accessory terminals to the track,, they are AC.


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## prrfan (Dec 19, 2014)

Jmstang302 said:


> Use the DC "track" terminals. Don't hook the accessory terminals to the track,, they are AC.


Yes and apparently that model controller has three sets of terminals : Variable DC (track),
AC (AC accessories) and Fixed DC (DC accessories).


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## bartlettbryce235 (11 mo ago)

ok thanks


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## Old_Hobo (Feb 20, 2014)

And do turn the throttle down….these are trains, not slot cars….


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## vette-kid (May 2, 2020)

I'd say run em at the speed that suits you. Some of my trains don't go all that fast even at full power. Or if I'm running a triple header on a long consist, full power seems a reasonable speed. 

Sent from my SM-G781U using Tapatalk


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## traction fan (Oct 5, 2014)

bartlettbryce235 said:


> So can I run a dc locomotive from this power source?


Many DC power packs have more than on pair of electrical outputs. These are screw terminals on the back of the power pack. One pair of screws should be labeled "track" or "variable DC" Those are the terminals that you should connect to your track feed wires. There may also be a pair of terminal screws labeled "AC" or "accessories" These screws output AC current and are meant to power things like switch machines and layout lighting, NOT TRAINS. If you connect these AC terminals to the track, they may well ruin your DC locomotive. Some power packs have a third pair of screw terminals labeled "DC". These output a constant DC voltage of about 12- 16 volts. They will not damage a DC locomotive, but it will only run at maximum speed. The speed control knob on the top of your power pack will have no control of how fast the locomotive goes. As you might suspect, these screws are also intended to power accessories, not trains. The only terminals that should ever be connected to your track are the first pair mentioned, labeled "Track", or "Variable DC." One screw terminal wired to each of the two rails of your track. The attached file explains how DC control of model trains works, and should be wired. It also covers the basics of how DCC works.

Traction Fan 🙂


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## Lemonhawk (Sep 24, 2013)

If you're using an A/C locomotive on normal DC HO track it will only short out as the wheels are on both sides of the loco are connected together (as the are in O gauge .


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## AmFlyer (Mar 16, 2012)

Hold on here. Gilbert prewar HO trains had universal motors and used two rail HO track. Just like postwar S gauge these train cars and engines have insulated wheels to allow operation on two rail track. With universal motors they will run on DC but the remote direction control feature will not function. They were designed assuming AC transformers from the Gilbert O gauge line would be used.


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## Lemonhawk (Sep 24, 2013)

Were talking 3 rail here not 2 rail.


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## MichaelE (Mar 7, 2018)

Another mole hill turned into a mountain.


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## AmFlyer (Mar 16, 2012)

Sorry. I thought we were discussing HO trains from some of the above posts.


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## sjm9911 (Dec 20, 2012)

Don't be sorry we were talking all trains , as the op didnt specify what he was running. Hes running ho. But we started with everything lol.


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