Cl 37 slow running and low power

[Jim]

I had posed this question on the "DCC sound" area with some good replies from "HLT 0109", McGomez" and "Legomanbiffo". I then found this section so thought I would chuck it in to see if anyone else has had the same problem.

 

The issue I have is with the slow performance of my three baccie 37s.

They all have v3.5 decoders re-blown with Howes refurb and original.

I use a NCE power pro controller.

The problem I've found is that they all run slow and when I set maximum speed cv5 to maximum the three models don't accelerate beyond speed step 80. They also struggle up gradients light engine.

 

Things I've tried:

I tried a guagemaster controller-no change.

I've experimented with speed and load cvs with no change.

I swapped the decoders from a 37 and a 47. (Howes re-blown 47)

The result was the fast 47 decoder in the 37 ran slow and the 37 decoder ran fast in the 47.

So, it must be something in the design. I lubed up the 37 but it didn't seem to need it. I lifted the motor chassis to have a look at the drive shafts and everything turned freely.

 

Anyone else noticed this kind of performance with their baccie 37s?

 

Jim

[34theletterbetweenB&D]

My perception is that Bach gear their diesels for appropriate maximum speed. The class 55 models noticeably shove along faster than plodders like 20 and 24. Can you run a 37 and 47 with their decoders removed on a DC supply and compare their maxima?

 

Lack of power and loss of any speed gain two thirds of the way through the speed step range seems very odd though. The Bach chassis uses the same motor whatever the model, and it has ample grunt. Switching the decoders between the 37 and 47 was a good move, as you now know that the problem is definitely associated with the 37 and this decoder type; but is not sufficient information to conclude that the problem is in the chassis.

 

What you are looking at I reckon is the result of interaction between the decoder design and the motor circuit of the 37 chassis. I have seen a few 'strange effects' between chassis circuits and decoders over the past half dozen years, and it usually comes down to a crude 'tuned circuit' present on the chassis, that just happens to interact with the decoder's drive or BEMF sampling frequency. Are you up for taking all the capacitors (usually 3) off the motor of one of your 37s? That's the kind of mod that typically fixes these problems.

[Jim]

Hmmmm,

I'll have a look at the capacitors tomorrow.

Thanks for that.

Jim

 

[Jim]

Just a thought,

What do the capacitors actually do?

Jim

[34theletterbetweenB&D]

In DC operation they act as conducting paths for the high frequency electromagnetic noise generated at the motor commutator, they provide the 'suppression' required. Bachmann usually put in three, one from each brush tag to motor casing, one bridging the brush tags. They can often be snipped out without dismantling the chassis.

 

In DCC they are redundant as the decoder supplies the required suppression. Because a capacitor stores charge and conducts proportional to rising frequency, they potentially interact with a decoder's non-continuous - typically 10s of kHz modulated - motor supply, and the back EMF which the decoder samples in the power off intervals to evaluate motor speed.

[ZippyHG]

I have had a problem when not using the original NEM couplings supplied. I found that on some couplings the prongs protrude into the bogie and catch on the gearing. i dont know where these couplers come from, but triming the prongs back or replacing them resolved the problem. it just a thought!

[Jim]

Well,

I've dismantled one of the 37s and there are no capacitors on or near the motor.

I removed the motor from the chassis and disconnected the drive shafts to each bogie then powered-up the motor. It responded through all speed steps which it does not do when connected to the bogies. It runs out of puff arround speed step 80.

On turning the drive shafts by finger I've noticed that the mechanism could be a little stiff. It's well lubed. This might be the problem? But would all three 37s have the same problem?

Jim

[Jim]

I noticed that one gear set was stiffer that the other so I stripped the bogie down to the individual pinions. They all moved freely but the worm seemed to be the cause of the stiffness.

I dismantled the worm gear from its mounting and looked at the brass bearings but couldn't find anything wrong or with the plastic mounting.

 

It's back together with no difference in running. All of them slow on curves and struggle up gradients light engine.

 

I have found though that if I set the load cv to 0 the locos don't move any quicker but respond to power steps to maximum. I suppose that maybe due to the load control when set to 64 detects some load on the motor (stiffness) and compensates by using more power.

However an "interesting" experiment it is, I'm bloody fed up and just whish manufactures could actually produce something that wasn't pants!!!!

Jim

 

[Mod5]

Jim just to assist others here your original post is here. We would far prefer you not to open up the same thread in different areas as it then becomes difficult for members to respond as one thing may have been said in one thread that affects something said in the other. So as well as linking to the other thread I have now locked it as it would appear not to be connected to the sound anyway.

 

Another point and one that has been repeated on here so often. If you are having problems with a loco then your first port of call is the supplying dealer. Your contract is with them and not Bachmann. You may well be competent to dismantle your loco but it would seem you are still in the same position. Your dealer however may be privy to more information than you and will have access to the Manufacturers as well. If you had problems with your tv, dvd player, washing machine whatever would your first instinct be to take it apart and therefore possibly prejudice any warranty complaint?

 

Of course if you for whatever reason are unable to take it to a supplying dealer you could contact the Manufacturer and give them the opportunity of repairing their pants product.

[Jim]

 

Thanks for the replies and ideas from you guys

Yes,

I got a bit hot-headed towards the end of my last reply! I looked out of the window and saw another day drawing to a close with no actual train running!!!

I have to add that my preferred loco manufacture is Bachmann!

 

The locos are too old now to take back. It's just frustrating that the power is there but it's being sapped somewhere in the drive train. Some more time is needed but will probably put up with it now since all three perform the same way.

Jim

[silverlink]

Jim just to assist others here your original post is here. We would far prefer you not to open up the same thread in different areas as it then becomes difficult for members to respond as one thing may have been said in one thread that affects something said in the other. So as well as linking to the other thread I have now locked it as it would appear not to be connected to the sound anyway.

 

Another point and one that has been repeated on here so often. If you are having problems with a loco then your first port of call is the supplying dealer. Your contract is with them and not Bachmann. You may well be competent to dismantle your loco but it would seem you are still in the same position. Your dealer however may be privy to more information than you and will have access to the Manufacturers as well. If you had problems with your tv, dvd player, washing machine whatever would your first instinct be to take it apart and therefore possibly prejudice any warranty complaint?

 

Of course if you for whatever reason are unable to take it to a supplying dealer you could contact the Manufacturer and give them the opportunity of repairing their pants product.

With all due respect many dealers haven't a clue when it comes to anything technical. Yes, there are some who have a great deal of knowlege & of course will help you but these are usually the specialists who work in depth with DCC & may not be the retailer you bought from . The manufacturer of the product may have an answer but making contact with someone can be difficult. On the other hand here on RMweb we have massive access to people with all the information you may need and this 24 hours a day 7 days a week. I think technical gremlins like this is bread & butter to many RMweb members as I'm sure we will see over the next few days.

silverlink

[Matt]

See the other post today on a class 37 with slipping drive. I've had this a few times and the effect is that the loco runs slowly and struggles up gradients - motor running fine but lots of wheel slip. On closer inspection find that drive only reaching one bogie and other is acting as hindrance to the loco moving. Have not yet remedied mine but believe it might be quite straightforward - sounds like you may have already looked at the mechanism so maybe you've eliminated this as a possible cause but just a thought...

 

M

[McGomez]

Hi Jim.

Could it be the infamous problem with the centre axle of each bogie that has often been mentioned on here?

I remember KEVPEO also mentioned this problem on his base enhanced speaker install which is to be found within the pages of RMWeb.

 

If the centre axle is slightly lower than the other two it causes a rocking effect which in turn could be causing the lack of adhesion.

I had this on my Bachmann 37410, Aluminium 100 and it was cured by removing the centre wheelset and filing the top of the plastic bearing/seating in the bogie frame with a very small diameter round file. This makes the wheelset sit higher up and obviously the other 2 axles in the bogie touch the tops of the rails and give far better grip.

 

 

I also remember a slight high point was found on the worm which made it sticky at a certain point.

This again was filed with a small flat file until it turned OK.

 

My loco can now haul around 20 Hornby PCAs up a 1 in 33 helix.

Top speed is slightly lower than a Bachmann Deltic, if that is any help?

[Jim]

Hi,

Thanks for more suggestions!

McGomez, I will definatley look at that centre axle and worm gear.

Jim

[Mod5]

With all due respect many dealers haven't a clue when it comes to anything technical. Yes, there are some who have a great deal of knowlege & of course will help you but these are usually the specialists who work in depth with DCC & may not be the retailer you bought from . The manufacturer of the product may have an answer but making contact with someone can be difficult. On the other hand here on RMweb we have massive access to people with all the information you may need and this 24 hours a day 7 days a week. I think technical gremlins like this is bread & butter to many RMweb members as I'm sure we will see over the next few days.

silverlink

 

 

I think you miss my point. If you do not want to invalidate your warranty then your first port of call is the supplying dealer. He does not have to know what the solution is all he has to do is contact the manufacturer (his supplier) on your behalf. There are many on here who will be able to help and who may well know what the problem is however that does not transfer the skill level to the op. Someone on here could more than likely tell me why my car computer keeps coming up with the same fault but I still wouldn't like to take it apart and chance making it worse when a warranty exists.

 

Even if a warranty has expired surely it is better to have a loco repaired by someone who knows how to. As it is the op seems fairly confident in his abilities but that does not mean everyone who reads this thread in the years to come will be. Don't forget this thread is searchable from within RMWeb and via any search engine so anyone looking for a solution to a similar problem will be able to see this. Rather than them think that they have to strip it themselves they may well also consider the option of returning to the supplying dealer. Sensible advice I would have thought.