drgj Posted March 18, 2019 Share Posted March 18, 2019 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 Link to post Share on other sites More sharing options...
cravensdmufan Posted March 18, 2019 Share Posted March 18, 2019 Dave, are you running it analogue or DCC? The reason I ask is because I had similar with my Hornby 153 - same type of motor i think. I'm DCC, and in the end I removed the capicitor and it's now super smooth. 1 Link to post Share on other sites More sharing options...
drgj Posted March 18, 2019 Author Share Posted March 18, 2019 Thanks for the reply, Vivian. I have a DC setup so my 101 is analogue. I bought this some time ago and the seller didn't mention the judder, of course! Dave Link to post Share on other sites More sharing options...
cravensdmufan Posted March 18, 2019 Share Posted March 18, 2019 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 Link to post Share on other sites More sharing options...
drgj Posted March 19, 2019 Author Share Posted March 19, 2019 Thanks, Vivian. I think I will strip it right down and give it a good clean out. Dave Link to post Share on other sites More sharing options...
Fireline Posted March 19, 2019 Share Posted March 19, 2019 It could be that the gear on one of the axles has a split in it. This would cause a judder, though maybe in certain places on the rotation, rather than all the time. 1 Link to post Share on other sites More sharing options...
drgj Posted March 19, 2019 Author Share Posted March 19, 2019 Thanks, Fireline. Will have a look. Dave Link to post Share on other sites More sharing options...
cravensdmufan Posted March 19, 2019 Share Posted March 19, 2019 8 hours ago, drgj said: Thanks, Vivian. I think I will strip it right down and give it a good clean out. Dave Dave, please let us know how you get on. Very interested in this. Thanks. Vivian Link to post Share on other sites More sharing options...
drgj Posted March 20, 2019 Author Share Posted March 20, 2019 Ok Will do it in the next day or two. I have already thoroughly cleaned the wheels and pickups to no avail. Dave Link to post Share on other sites More sharing options...
drgj Posted March 21, 2019 Author Share Posted March 21, 2019 (edited) 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 March 21, 2019 by drgj Link to post Share on other sites More sharing options...
Hroth Posted March 22, 2019 Share Posted March 22, 2019 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. 1 Link to post Share on other sites More sharing options...
cravensdmufan Posted March 22, 2019 Share Posted March 22, 2019 Dave, As you've tried everything else, maybe it would be worth snipping the capacitor off? Link to post Share on other sites More sharing options...
drgj Posted March 22, 2019 Author Share Posted March 22, 2019 (edited) 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 March 22, 2019 by drgj Link to post Share on other sites More sharing options...
cravensdmufan Posted March 22, 2019 Share Posted March 22, 2019 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 1 1 Link to post Share on other sites More sharing options...
drgj Posted March 22, 2019 Author Share Posted March 22, 2019 I will try a new motor at some point. Dave 1 Link to post Share on other sites More sharing options...
hucknall byron Posted March 28, 2020 Share Posted March 28, 2020 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. Link to post Share on other sites More sharing options...
hucknall byron Posted March 29, 2020 Share Posted March 29, 2020 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. Link to post Share on other sites More sharing options...
rembrow Posted March 29, 2020 Share Posted March 29, 2020 (edited) 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 March 29, 2020 by rembrow Clarification 1 Link to post Share on other sites More sharing options...
hucknall byron Posted January 20, 2021 Share Posted January 20, 2021 Just as a matter of interest has anyone fitted a replacement motor? Looking at pictures of the X9674 they do not seem to have the connecting wires fitted? Does this mean splitting it and soldering on replacements? Link to post Share on other sites More sharing options...
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