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Digitax Zephryr - Slow Top Speed

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Digitax Zephryr - Slow Top Speed
Posted by don7 on Monday, February 28, 2011 8:35 PM

I recently upgraded my DCC from a basic Bachmann EZ command system to a Digitrax Zephry.

i am very disappointed with the top speed of the Digitrax unit. I checked the Zephry's setting and the top speed is set to the units max. Both DC and DCC engines are equally affected.

The digitrax unit's top speed is set correctly.

The top speed of the Digitrax is only about 2/3 of the Bachmann EZ Command. The Zephyr reaches top speed at setting 4 and does not increase speed through setting 5 or the max 6.

I have about 55' of mainline track on my layout. Would adding more feeders help? Is there anything I could try.

I contacted Digitrax but was given no advice other than the Voltage of the EZ command at 16 volts is higher than the Digitrax at 14 volts.

 

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Posted by rrinker on Monday, February 28, 2011 10:33 PM

 This is a model railroad not a race track. Every loco I have goes MORE than fast enough at full throttle - what locos and what decoders are they? The Zephyrs track voltage is a bit lower than some since it is designed to work with all scales not just HO and larger. The lower voltage also means your light bulbs will last longer, and not melt the shells.

 Since you had an EZ before, I doubt any CVs got set, but depending on the decoders make sure CV 2, 5, and 6 are all set to 0 and check your value of CV29 to make sure it isn't using a speed table.

                      --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by tstage on Tuesday, March 1, 2011 12:49 AM

Don,

Have you tried actually calculating scale speed (sMPH)?  What may seem slow to you might actually be going prototype speed.

I have a 3' section on my layout that I use for checking speed, which is a basic Point A and Point B setup.  I measure the time it takes a locomotive to travel between the two points then look up on my chart (that I created in MS Excel) to see what speed it's traveling at.

For example, say a locomotive takes 10.5 seconds to travel 3'.  The chart below first calculates V[elocity] = D[istance]/T[ime] to find ft/sec.  It then converts that value to mi./hr. (or MPH) then multiplies it by 87.1 (HO) to get sMPH:

Distance/Time Total Convert to mi./hr. HO TOTAL
(ft.) (sec.) (ft./sec.) x ÷  x sMPH
3 10 0.30 5,280 3,600 87.1 38.32
3 11 0.27 5,280 3,600 87.1 34.84

[Oops! Embarrassed - Edited]

Distance/Time Total Convert to mi./hr. HO TOTAL
(ft.) (sec.) (ft./sec.) ÷  x x sMPH
3 10 0.30 5,280 3,600 87.1 17.82
3 11 0.27 5,280 3,600 87.1 16.20

So, a locomotive taking 10.5 seconds to travel between Point A and Point B is traveling at ~36.6 ~17 sMPH.  I have my chart mapped out from 1 sec. to 60 secs. and hanging up on the wall for reference.  For slower or switching speeds, you could have another chart for a 1' and 3" section of track.

If you have a locomotive with sound, some sound decoders (e.g. QSI) will give you an audible sMPH feedback on the fly when pressing F10.  However, even though chuff and primer mover sounds are reduced by 1/2 so that the feedback command can be heard, I still find it difficult to make it out.  The chart works quite well for me.  I just use the stop watch feature on my cell phone to get an approximate time.

Hope that helps...

Tom

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Time...It marches on...without ever turning around to see if anyone is even keeping in step.

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Posted by richg1998 on Tuesday, March 1, 2011 7:16 AM

He got the same answer in the Bachmnn forums.

http://www.bachmanntrains.com/home-usa/board/index.php/topic,16405.0.html

Rich

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

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Posted by don7 on Tuesday, March 1, 2011 4:02 PM

Tom,

I can not get your formular to calculate the same total as you.

I was given another formular off the Bachmann Board for speed.

Scale MPH = ((L x F/12)/5280) x 3600/T

Example: If it takes 5.2 seconds for a HO locomotive to travel over two straight pieces of Bachmann sectional E-Z Track.
L = length of travel in inches: 18 inches
F = scale factor: 87.1
T = time in seconds: 5.2

Scale MPH = ((18 x 87.1/12)/5280) x 3600/5.2 = 17.1 MPH 

---------

To use   Microsoft EXCEL
Cell A1 enter length travel in inches
Cell A2 enter scale factor
Cell A3 enter time in seconds
Cell A4 enter the scale MPH formula  =((A1*A2/12)/5280)*3600/A3

Using that formular the example of 3 ft in 10 seconds equates to 17.8 MPH

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Posted by PRR_in_AZ on Tuesday, March 1, 2011 4:09 PM

Don,

I, too, have a Zephyr and have noticed exactly what you are saying.  I think it sucks!  I test my engines on DC before hooking up the decoder to make sure the mechanism is working correctly.  I use a railpower 1300 basic transformer and I get waaay better throttle response and top speed from that power pack than my Zephyr.  I have the older model Zephyr.  My Zephyr too tops out when the throttle is slightly past 4 also.  Why the heck put 5 and 6 on there?  To me, this is poor.  And yes, I know it's not a race track, blah, blah, blah.  Before I start building my layout I'm thinking of upgrading to a handheld throttle and separate booster.  The digitrax booster has a switch on the side that will allow you to run at a higher maximum voltage.  The only thing I can recommend is using a power source that puts out more voltage.  Something like 14-16 volt.

Chris

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Posted by don7 on Tuesday, March 1, 2011 4:26 PM

Chris,

I heard back from Digitrax and they suggest I add one of their boosters (DB150) which has a switch for N and  HO guages, this would increase the voltage from 14 to 16 volts.

I unpacked a MRC Prodigy DCC controller that was given to me and tried it. Now that unit is rated at 16 volts and gives me a more realistic top speed. The MRC is limited to two number addresses but I can work around that. The MRC Prodigy is actually not that bad a unit.  

I think I will use the MRC unit on my main layout and keep the Zephry attached to my test track for now.

Should I need to change CV's I can change them on the test track with the Zyphry. 

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Posted by PRR_in_AZ on Tuesday, March 1, 2011 4:34 PM

Don,

Yep, I came to the same conclusion after reading about the DB150 too.  Thanks for sharing though!  I don't know why this bothers me because I don't wish to run the trains fast, but somehow I feel I'm being cheated by having all this throttle left.  I really do feel this is a failing of the Zephyr and I shouldn't have to buy a separate booster to get performance similiar to other entry level DCC systems.

Chris

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Posted by don7 on Tuesday, March 1, 2011 4:54 PM

rrinker

 This is a model railroad not a race track. Every loco I have goes MORE than fast enough at full throttle - what locos and what decoders are they? The Zephyrs track voltage is a bit lower than some since it is designed to work with all scales not just HO and larger. The lower voltage also means your light bulbs will last longer, and not melt the shells.

 Since you had an EZ before, I doubt any CVs got set, but depending on the decoders make sure CV 2, 5, and 6 are all set to 0 and check your value of CV29 to make sure it isn't using a speed table.

                      --Randy

 I can tell the difference between a model railroad and a race track.

I am running BLI steam and diesel,  Stewart diesels, Intermountain diesels , Proto 2000 diesels and steam and Spectrum steam engines, mostly sound equipped. Active roster is around 30 engines at any given time.

I alternate my layout between 1900 and 1960 by changing rolling stock, engines vehicles and some structures. The total number of engines is around 65. Most are DCC, only around a dozen or so to change over to DCC or DCC/Sound.

 I never thought that I would ever turn the throttle to full speed to obtain a reasonable running speed. The speed does increase to number 4 on the throttle, no increase for 5 or 6 (the top speed) is noticeable.  

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Posted by CSX Robert on Tuesday, March 1, 2011 8:17 PM

tstage

...

Distance/Time Total Convert to mi./hr. HO TOTAL
(ft.) (sec.) (ft./sec.) x ÷  x sMPH
3 10 0.30 5,280 3,600 87.1 38.32
3 11 0.27 5,280 3,600 87.1 34.84

...

You should be dividing by 5280 and multiplying by 3600, not the other way around.

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Posted by rrinker on Tuesday, March 1, 2011 8:19 PM

 If you aren't getting any speed increase from the 4 spot ont he throttle knob to the 5 and 6 spots, then something is not set correctly. There is a speed limit function built in the Zephyr, mainly so you can let kids run it and not run everything at warp speed. This is indpendent of the max volt CV5 in the decoder.  See page 14 of the manual and check that yours is set to 99 - or just do an OpSw 39 reset since unlimited top speed (99) is the factory default.

 I have a DB150 connected to my track yet I usually run int he N scale (12 volts) setting because my loco go plenty fast enough. They were fast enough with just the Zephyr powering the tracks as well. The extra bit of information that you get no more speed increase from about halfway to full throttle tells me somethign else is wrong here and it's not the track voltage. Besides the internal speed limit ont he Zephyr itself, you might also want to check CV2, 5, and 6 to make sure a 3 step speed curve isn;t being used, and make sure there's not a 28 step speed curve programmed in (non of this is possible with just the EZ Command, since it can't prgoram CVs), and also check the value of CV29 and see if it's set for 14 or 28/128 speed steps - and check that you are using the same on the Zephyr. Out of the box it defaults to using 128 speed steps to control te decoders - see the section on 'status editing' about this and make sure you didn;t accidently do this - again the OpSw 39 reset will clear all that stuff out on the Zephyr side.

                        --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by rrinker on Tuesday, March 1, 2011 8:30 PM

 Speed calc is right, 18" of track in 5.2 seconds is 17mph. in 1 second it's 88mph - that's when the fun stuff happens!

2s is 44mph, 4s is 22mph.

               --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by tstage on Tuesday, March 1, 2011 9:27 PM

Thanks, Robert.  After Don came up with a different number I went back and discovered what I had done wrong.  Tried to get back on this thread the past couple of hours to make the correction but the thread would only partially load.  Anyhow, I just edited my post so that it's correct now.

Guess I need to take a basic algebra class again. Dunce  What a maroon! Embarrassed

Tom

https://tstage9.wixsite.com/nyc-modeling

Time...It marches on...without ever turning around to see if anyone is even keeping in step.

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Posted by CSX Robert on Tuesday, March 1, 2011 9:31 PM

Have any of you guys who are unhappy with the top speeds you are getting from the Zephyr actually measured your locos' top speeds?  I don't have any personal experience with HO DCC equipped engines(I'm an N scaler myself), but from what I have heard most people are quite satisfied with what they get from the Zephyr.

As far as not getting use of the full range of the throttle, unless there is something physically wrong with your Zephyr, this is most likely caused by a combination of Bemf compensation settings in the decoders and the lower track voltage.  Bemf compensation works by increasing or decreasing the decoder motor output to try to reach a set bemf voltage from the motor.  Depending on the combination of decoder, motor, and track voltage, sometimes the track voltage is not enough to turn the motor fast enough to get what the decoder expects as the maximum bemf voltage.  When this is the case, the decoder will be supplying full voltage before it gets to it's maximum speed step and will, naturally, stop accelerating.  If this is the case, although it won't increase the top speed, decreasing CV5 and 6(max and mid voltage) will spread out the speed range using more of the throttle.

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Posted by PRR_in_AZ on Wednesday, March 2, 2011 11:34 AM

I played around with the Z last night trying suggestions that Randy and Robert made.  What I found was that by turning off BEMF I was able to get a slightly better top speed.  The engine didn't start moving until about 2.5 on the throttle handle but did have an increase in speed all the way through to 6.  All it really did was put the dead space at the beginning of the throttle instead of the end.  Thanks for all the great suggestions but I really doubt I'm going to get anything better out of this device.  I think I'm going to try one more thing tonight.  I have a BLI steamer with factory installed QSI sound decoder.  If the throttle range is good for this steamer than I can eliminate the Z and maybe focus my attention to some unusual setting in the decoder.  I may even purchase a different brand of decoder and try that.  I'll post findings.

Chris

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Posted by CSX Robert on Wednesday, March 2, 2011 12:32 PM

PRR_in_AZ

...What I found was that by turning off BEMF I was able to get a slightly better top speed.  The engine didn't start moving until about 2.5 on the throttle handle but did have an increase in speed all the way through to 6.  All it really did was put the dead space at the beginning of the throttle instead of the end...

Increasing CV2(start voltage) would get rid of the dead space at the beginning of the throttle when Bemf is not enabled.

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Posted by PRR_in_AZ on Wednesday, March 2, 2011 1:26 PM

Increasing CV2(start voltage) would get rid of the dead space at the beginning of the throttle when Bemf is not enabled.

Hmmm, tried that but it didn't seem to do anything to alleviate the dead space.  I'm wondering if adjusting CV05 and 06 to a lower value would help?

Chris

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Posted by rrinker on Wednesday, March 2, 2011 8:39 PM

 It's hard to do with the Zephyr alone, but with a DT40x throttle so you KNOW you are on speed step 1, the thing to do is set speed step 1, then adjust CV2 untilt he loco cna move as slow as it can reliably. You should then have no dead space at the beginning of the throttle movement, beyond the potentiometer hardware. Depending ont he loco, with no BEMF the needed value for CV2 can be fairly high. Use Ops Mode to keep adjusting it with the throttle just off stop until the loco moves.

Adjusting CV5 will stretch out the top end of the throttle but it will also reduce the overall top speed of the loco. WHat you are doing with CV2 and CV5 is increasing the voltage applied to the motor at speed step 1, and decreasing the voltage applied at speed step 128 (ok there are couple of reserved steps so it's not really 1-128 - let's keep it siomple here for the sake of the argument). So now instead of 1-128 causing a change of say 0-12 volts, it now makes a change from 3-10 volts, but the same number of steps - so each step is smaller and you have finer control.

                                    --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by PRR_in_AZ on Wednesday, March 2, 2011 10:54 PM

rrinker

potentiometer hardware. Depending ont he loco, with no BEMF the needed value for CV2 can be fairly high. Use Ops Mode to keep adjusting it with the throttle just off stop until the loco moves.

 

Ya, I'm kinda finding that out as I had CV02 up to 10 and still hadn't taken up much slack on the front end.  Also the motor seemed to sing.

Chris

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Posted by rrinker on Thursday, March 3, 2011 7:13 AM

 What decoder is in it? A singing motor is usually a sign of not using high frequency drive - the high frequency drive is usually above hearing range whereas the non-high frequency drive can make the motor sound like it's running on address 00 with no decoder.  Some decoders have really good motor control even without BEMF - TCS with BEMF turned off or the older TCS before they even had BEMF, and the NCE D13's are a few. With TCS there are quite a few adjustments for the 'dither' which is what they call it - that's NOT BEMF, their BEMF is automatic, the only real adjustment for TCS BEMF is when it drops off - they allow you to have BEMF in the lower speed steps to get started but then at faster speeds it drops off so you don't have a cruise control effect.

                  --Randy


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by PRR_in_AZ on Thursday, March 3, 2011 11:39 AM

rrinker

 What decoder is in it? A singing motor is usually a sign of not using high frequency drive - the high frequency drive is usually above hearing range whereas the non-high frequency drive can make the motor sound like it's running on address 00 with no decoder.  Some decoders have really good motor control even without BEMF - TCS with BEMF turned off or the older TCS before they even had BEMF, and the NCE D13's are a few. With TCS there are quite a few adjustments for the 'dither' which is what they call it - that's NOT BEMF, their BEMF is automatic, the only real adjustment for TCS BEMF is when it drops off - they allow you to have BEMF in the lower speed steps to get started but then at faster speeds it drops off so you don't have a cruise control effect.

                  --Randy

Is TCS Torque Control?  My decoder has that along with Digitrax's (super sonic?) silent feature.  Maybe I had torque control turned off when the motor was singing.  I can't remember the decoder type off the top of my head.  I'm at work so I'll have to check at lunch.  BTW, I tested my BLI steamer last night and it runs very vast on the Z at top speed.  I wouldn't neeed anything close to that.  Throttle control is decent with default settings but it doesn't start moving until around 2 on the dial, but has constant speed increase all the way up.  I'm wondering if the gearing is lower in the old brass engines than in these newer RTR locos?  Although that doesn't really explain why the old brass loco ran much faster with the Railpower transformer.  The Railpower transforner is putting out 15 volts, though.

Chris

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Posted by rrinker on Friday, March 4, 2011 11:15 AM

 TCS calls their non-BEMF motor adjustment 'dither'. They are high frequency driver and shouldn't buzz. Even the newer TCS decoders with BEMF have an option to disable BEMF and use dither instead. I have some locos with older TCS decoders in them that after tweaking start up and run very slowly. The differenc is I had to tweak the settings to get those to run slowly, the new TCS decoders with BEMF they already run nice at slow speed without adjustment.

                       --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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