Current Draw of Rivarossi 2 8 8 2?

[MarioBarb]

Hi

Just purchased a second hand Rivarossi 2 8 8 2. Runs well, but draws between 0.5 and 0.7 amps. Is that normal? If no, what's the potential issue, and does any one have service diagrams for this loco? (My lima locos draw less than 0.25 amps, so this just seems a little high)

Thanks

Mario

 

[doctorwayne]

Depending on how old your loco is, it may have the old 3-pole motor, which wasn't particularily impressive. The current draw does seem excessive, though. Have you disconnected the motor from the drive train, to check the chassis mechanisms for binding? Another cause of excessive current draw is partially damaged insulation on the motor windings, usually as a result of overheating. Once this problem starts, it more-or-less feeds on itself until the motor dies. If the mechanism is free-rolling with the worm disengaged, you might want to investigate replacing the motor with a suitable can motor, which will substantially lower current draw and give you much better speed control.

Wayne

 

[MarioBarb]

2 8 8 2 rivarossi motor

Hi Wayne and thanks. I decide to disassemble the motor to check it out- and spent the next three hours trying to work out which ball bearings go where! Tiny little buggers - not advice I would recommend to anyone especially if your eyes are going to hell. Anyway, I reassembled it after reversing the one worn brush, and it seems to go Ok, bit noisy, but it is still drawing the same current. The mechanical side of things seem OK (drive train etc).

Any advice on a replacement motor, and availlability in New Zealand?

Thanks

Mario

 

[doctorwayne]

Mario, I checked my NorthWest Short Line catalogue, and they recommend their 2032 can motor. However, my catalogue is over ten years old, so you might want to check with them. Here's a link to their site:
NorthWest Short Line

Their catalogue, besides showing their products, also offers some good tips for remotoring and re-gearing locos, and is well worth the cost. They may have a more suitable motor available now: this one supposedly protrudes into the cab somewhat, depending on the particular loco. They also offer regearing kits for your loco, but note that remotoring and re-gearing may result in a loco that runs too slowly. Good luck if you decide to proceed with this, and don't be afraid to ask questions if you get stuck. I've done quite a few remotoring jobs, both for myself and others, and most of them are quite simple to do.

Wayne

 

[MarioBarb]

Its working

Hi Wayne and thanks for the advice. I managed to get the whole thing working again and its drawing slightly less current Max 0.55 amps, and is not too noisy. The brushes may have been the problem. Also the voltage has increased to =10v, from a max of about 9v. One strange thing is that when I use a straight 12v transformer, it runs much faster, but when I use a train powersupply (also rated at 12v) it will only get to about 10v. Any ideas on why this is so?

Once again thanks

Mario

 

[doctorwayne]

Sorry Mario, but I can't help you with the voltage issue: if I can get a loco to run smoothly without liberating any smoke from the motor, I consider it a job well done!

Wayne