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Hornby Class 101 Slow Running


drgj
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I have a Hornby three car class 101. At the very slowest speed  as when pulling away it judders as if it can "feel" every turn of the armature or maybe the gear teeth in a similar way.  It has the motor bogie that Hornby used to replace the old Lima one. I have cleaned the wheels and it seems to be well lubricated. I bought it second hand and maybe it wasn't run in properly or maybe I just need to run it in. I wonder if anyone else has had trouble with this kind of motor bogie.

Thanks

Dave

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That's a shame - not sure if nipping through the capacitor wire helps with smoother running on DC (maybe other members could advise?).  You could try it Dave, and solder it back on if it makes it even worse!

 

Other than that I don't know what to suggest except maybe there's a small bit of ballast or similar caught in a gear cog? Maybe worth a strip down? Doesn't look too daunting: https://www.Hornby.com/_assets/files/service-sheet-hss-no-301e-428(1).pdf

 

Vivian

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I stripped the motor bogie right down. It is a simple affair but leaving all the wires connected made the job a bit more difficult as it meant that the two halves of the disassembled  motor bogie and the motor itself  had to remain dangling from the chassis. Undoing the screws holding the 8 pin socket allowed a bit of slack.  I used isopropyl alcohol for the cleaning. All the parts turned freely with no broken teeth on the gears. The motor revolved ok by hand. it has very strong magnets and I could really feel them when turning the armature. I put bogie  back together and lubricated it with some Daywat lubricating oil which is safe on plastic.  The result is that it is exactly the same!  As it is so simple then maybe the motor is at fault for some reason. The complete motor bogie judders when it  starts off but then suddenly becomes very smooth as it speeds up slightly.

 

Dave

Edited by drgj
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I think your observation that the motor appears to have strong magnets explains why it appears to judder at very slow speed and smooths out as it goes faster.  Its not a "fault" just that at very low voltages, the armature jumps from one magnetic pole to another as it rotates. This is called "cogging". As the supply voltage increases, the magnetic field in the armature balances the forces more easily and the motor smooths out.

 

Its swings and roundabouts, a higher gear ratio would allow the motor to run faster for a given road speed and would mask the juddering, but the apparent maximum speed of the loco/dmu would be slower and while slow speed performance might be more acceptable, would give the appearance of somewhat sluggish performance at the high end. On the other hand a lower gear ratio would give a more realistic maximum while demonstrate the low-speed "juddering" you have noticed.

 

 

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Thanks for the replies.

 

It seems a bit too juddery to be cogging. The change from juddery to smooth is sudden, as well.  I wonder if any other locos or units with this bogie type suffer the same way? If this is normal running then I'm sure no one would buy them. It must be fitted to all ex Lima models. Not sure about the capacitor as it usually doesn't cause any trouble but I may have a look at the connections again.

I might send a message to Hornby about it.

Dave

Edited by drgj
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3 hours ago, drgj said:

I wonder if any other locos or units with this bogie type suffer the same way?

Dave, I have a couple of Hornby (ex Lima) 101s, a Class 153, and a class 87 all with that type of motor.  All are very smooth runners right from crawl through all speed steps to maximum so i don't think your's is a common problem. Of course, unfortunately you may have a rougue one, and as you mentioned could be why the previous owner sold it.

 

Have you tested the motor on it's own, not connected to the wheelsets?  If it is the motor thats faulty, then a replacement is available quite cheaply ref X9674 e.g. https://www.newmodellersshop.co.uk/hornby_spares/x9674_hornby_spares_motor_skew_wound_5_pole.htm

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  • 1 year later...

I have the same problem, I have a thread on here asking the same questions and I decided to change the decoder which I did this morning. I am starting to invest a fair amount into this relatively old model but I have a soft spot for it having detailed it and got it looking decent. I will be very interested to know if a new motor solves the problem before I think about doing the same. 

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Having nothing else better to do I have spent a couple of hours at least polishing the wheels. I have used brasso on cotton buds and have achieved close to a mirror finish. The improvement in running is remarkable. The loco is pretty much faultless now apart from a tendency ( not always) to require a push from a standing start. Am I right in saying that the wipers are only on the non motor bogey end? I don't have the confidence to strip it down. Any suggestions to get rid of the "push" start.

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1 hour ago, hucknall byron said:

Having nothing else better to do I have spent a couple of hours at least polishing the wheels. I have used brasso on cotton buds and have achieved close to a mirror finish. The improvement in running is remarkable. The loco is pretty much faultless now apart from a tendency ( not always) to require a push from a standing start. Am I right in saying that the wipers are only on the non motor bogey end? I don't have the confidence to strip it down. Any suggestions to get rid of the "push" start.

If you have the Hornby version, rather than the earlier Lima version, it should have all wheel wiper contact pick up, on all 4 non motorised bogie wheels and all 4 motor bogie wheels, even though 2 wheels on the motorised bogie have traction tyres.

The motorised bogie wheelsets pull off once you remove the keeper plate, which is held on by plastic clips. Once a motor bogie wheelset is pulled off you should see the contacts, which are quite thick and will spring to the side where the wheels were. When replacing the wheelset you need to ensure these are pushed in towards the motor assembly, as you drop in the wheelset, otherwise they could be bent out of position.

It may be worth also checking that the contacts and wiring to the unmotorised bogie are intact, as without that you only have contact to the 2 wheels in the motorised bogie that don't have traction tyres.

 

Edited by rembrow
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  • 9 months later...

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