B12 running very hot

[CobblerBob]

Hi,

I recently got my hands on a B12 model from ebay. My understanding from hornbyguide that this is R.866 from 1978/79 (based on the box design).

It runs well it terms of speed/noise, but gets really hot really quickly. I've done a basic service (cleaned/lubricated), but no change.

However, something I've not had before is that the whole chassis seems magnetically charged. The wheels can hold a very small screwdriver!

I assume this is why it's running hot (but don't know a huge amount, so could be very wrong!). But no idea how to fix it.

Any help greatly appreciated.

[Chrissaf]

The age of the loco means that it could be fitted with the Hornby / Triang Magnahesion feature. This is a magnet that attracts the loco wheels and chassis to the old steel track rails to increase traction. If your loco is fitted with Magnahesion then the screwdriver sticking would be perfectly normal and probably nothing to do with your heat issue.

These old loco motors can suffer from loss of magnatisim in the motor magnets (different magnet to the Magnahesion magnet), this loss of motor magnet strength causes more current to be drawn from the controller to maintain the same speed as before. More current equates to more power consumption and power consumption translates directly into heat. Since you say that the loco drives reasonably well, it just gets hot. I would suggest sending the motor off to 'Scalespeed' to have the motor remagnatised and checked over. If you do nothing, the heat could potentially cause the motor windings to eventually fail.

At the top of the 'General Discussion' forum is a sticky thread titled 'Useful Links', a clickable link for 'Scalespeed' is listed there.

This YouTube video demonstrates this weak strength magnet drawing more current issue.

As this is your first post and my reply is a long one. Please do not use the blue button. Scroll down to the bottom of the page and write any reply you want to make in the 'Reply Text Box' and then click the green 'Post Reply' button.

[Potterton]

Is your B12 fitted with the syncrosmoke generator and, if so, are you running it dry? I asked about this in a previous thread "smoking trains (Chimney not Motors)", and it was suggested that doing so could cause excessive heat build up.

[The son of Triangman]

Syncrosmoke alas went out of production at the end of 1973/early 1974 as a cost cutting exercise so unlikely on a 1977/78 version of the model unless someone has fitted it outside of the factory. Most likely the magnet is weak and the motor coils are drawing more current causing the motor coils to heat up. As has been said the coils left to their own devices will heat up until they draw more current than they can take and will fail. A good service and a remagnetise is the order of the day if it's the motor, "Scalespeed" do remagnetising and repair of these motors.

[Potterton]

@The son of Triangman "Syncrosmoke alas went out of production at the end of 1973/early 1974 as a cost cutting exercise so unlikely on a 1977/78 version of the model"

Fair enough. I wasn't aware of that. Thanks. grinning

[ColinB]

Can you not just buy a new magnet for the motor. That is what I did with my Wrenn locos. If it is an X03 or X04 the magnet can be replaced.

[The son of Triangman]

I wouldn't recommend a neo magnet, they tend to be too powerful and can cause extra bearing wear as they pull on the motor armature shaft.

[CobblerBob]

Many thanks all for the advice. I hadn't thought about Magnahesion being the reason for the magnetic wheels, obvious when someone else points it out!

Think I'll get it booked in to Scalespeed.