How to tell 4.5V motor from 12V motor

[roamingstop]

I would like to know how to tell the difference between a 4.5V motor and a 12V motor - especially when the pickup adapter bricks are used?

Especially the Type I old motors - which appear to look identical

I think I have a 4.5V and a 12V from a recent auction lot, but no way to work out, and I dont want to plug in the adapter plates and blow the motor.

Also some of these adapter parts rattle with what appears to be a loose internal element - is that normal? Did they contain capacitors / resistors?

[Ralph_S]

I never had any of the adaptors, so I can't answer that question. You can identify the motor through the little window in the top. You can read the label on the actual electric motor inside it. It will read either 4.5V or 12V.

If you can't read it, you can take off the top by undoing the two screws and read the label then.

Cheers,

Ralph

[harnbak]

Some additional (historic) info here: http://horst-lehner.mausnet.de/lego/ben/9v_12v.html

[Mirandir]

Now I'm no expert on electronics but shouldn't it be safe to feed a 12v motor with just 4.5 volts. If it's a 12v motor it would reveal itself by moving slower than normal.

Edited September 23, 2011 by Mirandir

[Gareth]

There are no resistors or anything in the adaptor plates it is just an extension so the motor can pick up the current from the bottom of the track but they do rattle and move to adjust for the gradients of the track, the original train 12volt motor has the same things on the bottom of it too, they are just another way of getting power up from the rails just like the wire from a battery box.

Be careful on Brick-link buying those motors you can see the numbers on the top but there were some sellers sellling 4.5volt motors for 12volt I got stung with that one, and I have quite a few 4.5 motors now.

When you run them on the track remember to turn the power knob up side down this is so you can safely run 4.5volt motors on it, but honestly I haven't noticed anything wrong with running them on 12volts just not continuously I suppose they wouldn't like that.

I hope this helps!.

[LEGO Train 12 Volts]

To chek out if the motor is 4,5 or 12 Volts you can open it removing the two housing screws: on the motor you can read the voltage on the label.

In the adapter plates there are only two springs to transmit power from the track to the motor (no resistors or any other components)

[peterab]

I would like to know how to tell the difference between a 4.5V motor and a 12V motor - especially when the pickup adapter bricks are used?

Especially the Type I old motors - which appear to look identical

The casing of the motors are identical, only the motors themselves differ. An easy way to differentiate from outside is the label on the motor, the 4.5V has 4.5V printed on a red background, the 12V has 12V printed and a yellowish green background. You can sort of see this colour difference though the little hole on the top of the case in your pictures. The other difference is the gearing of the motors. The metal cog on the shafts are in different spots, so they drive a different size gear in the case. The 12V motor drives the larger gear (thus gearing it down more) I think.

[roamingstop]

Thanks for all the hints - sometimes the obvious one is easy to miss... I just need to find some time to open up one of them... there is definitely a 4.5V and a green square... which could mean anything.

[BillytheKid]

At the top, between the studs you can see a red dot or a yellow one. The red one is a 4V motor and the yellow one the 12v motor.