Live rail Posted January 23, 2022 Share Posted January 23, 2022 Hi folks,I have just fitted a loco with a Zimo decoder and set the address and functions.The unit performs OK except that the top speed is not that great. Up to half throttle is fine, but further movement of the throttle makes no difference to the speed. Are there any adjustments that I can make to improve top speed?I am using a Digikeijs DR5000 power unit and Z21control on my smart phone.All the other locos perform fine, although some are faster than others, of course.Thanks for any input. Link to comment Share on other sites More sharing options...
Chrissaf Posted January 23, 2022 Share Posted January 23, 2022 There are members on this forum who use Zimo decoders, DR5000 and Z21, but not necessarily all together. So I would expect some useful replies to be made.But in order to complete the full picture for those members to give a targeted reply, it would be ever so useful if you could also advise which model has the Zimo decoder fitted to it. It may be that the issue is common to the loco rather than your stated components.Please note that as this is your very first forum post that it would also be helpful if replies are made using the 'Reply Text Box' at the bottom of the page, rather than the within post 'Blue button'. Link to comment Share on other sites More sharing options...
Live rail Posted January 23, 2022 Author Share Posted January 23, 2022 Thank you Chrissaf,The model is the tube train from EFE. They have coreless motors whatever they are! Link to comment Share on other sites More sharing options...
Chrissaf Posted January 23, 2022 Share Posted January 23, 2022 Ahh.A coreless motor.I'm not expert on coreless technology, but coreless motors have recently been discussed. It seems from posts made during that recent discussion that they do not work well when using 'BEMF feedback' controllers. That comment relates to Analogue control rather than DCC, but decoders typically use 'BEMF feedback' enabled for speed control.This could be a significant contribution to your issue.Coreless motors produce less BEMF [back Electro Magnetic Force], the more BEMF that the decoder detects then the more power is applied to the motor. The lack of BEMF from your coreless motor may be limiting the power applied, thus limiting its speed.I suggest as an experiment you look in your Zimo decoder manual and search for any CV that can be set to disable BEMF and test again if you find you can disable it. Link to comment Share on other sites More sharing options...
Brew Man Posted January 23, 2022 Share Posted January 23, 2022 Did the loco run any faster under DC control? I know some locos have circuitry built in to limit the speed in order to emulate prototypical behaviour. An example is the Oxford Rails Adams Radial. It has resistors on the DCC socket to drop the voltage fed to the motor. Link to comment Share on other sites More sharing options...
Live rail Posted January 23, 2022 Author Share Posted January 23, 2022 Both your comments make a lot of sense to me and I hadn’t given it much thought until you mentioned it. I don’t have a DC test track Brew Man but I may have to set one up if I’m to try these tests. Maybe, as you say, there is a built in speed limiter as Tubes don’t run that fast in real life. I’ll check what you and Chris suggest and keep you posted. Thanks for help fellas. Link to comment Share on other sites More sharing options...
96RAF Posted January 23, 2022 Share Posted January 23, 2022 You do have a DC test track Michael (your nickname apparently is a banned word) - simply disconnect your DCC controller and hold a 9v battery across the rails. This will give you a reasonable voltage to gauge if the loco is working well enough or not. Link to comment Share on other sites More sharing options...
Live rail Posted January 25, 2022 Author Share Posted January 25, 2022 Now why didn’t I think of that RAF? Duhh! Good idea. Incidentally I read the Zimo manual as suggested by Chris and found that CV5 controls the top speed. It’s too cold at the moment to go to the shed to set it up but I shall see about it at the weekend. Thanks for all your help folks. Link to comment Share on other sites More sharing options...
Fishmanoz Posted January 25, 2022 Share Posted January 25, 2022 That’s the standard CV for Vmax on decoders which support it (not supported by Hornby decoders). But default is maximum so chances are adjustment will only decrease top speed. Link to comment Share on other sites More sharing options...
Live rail Posted January 26, 2022 Author Share Posted January 26, 2022 Thanks for the tip Fishmanoz. I’ll experiment and see what happens. It’s all good for learning! Link to comment Share on other sites More sharing options...
RDS Posted January 30, 2022 Share Posted January 30, 2022 @MickModerator Note:Could you please select the 'View my Community’ in your Dashboard on the Forum and choose a nickname in the ‘My profile' tab, rather than your First name that has been automatically allocated by the system. Hopefully a Forum change is coming soon to prevent this automatic allocation but a manual change is required at the moment and there will be more than one member with your name. Link to comment Share on other sites More sharing options...
DBfan Posted February 6, 2022 Share Posted February 6, 2022 Don`t forget that some models are geared to represent the correct top speed of the prototype in model form. Tube trains do not go as fast as HST125 so the model is probably geared to represent that. I once had someone return a Bachmann 08 because it would not go as fast as his other locos. He would have it that given the prototype would only travel at 15 to 20 mph Bachmann had geared it accordingly, he just wanted all his locos to belt around the track at 100 MPH Link to comment Share on other sites More sharing options...
96RAF Posted February 6, 2022 Share Posted February 6, 2022 Reset the decoder to defaults to set the standard speed curve. Yours describes a cropped top speed in CV5 without amending CV 6 to match.If you can, read those two CVs and you should see 255 and 128. Link to comment Share on other sites More sharing options...
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