I think I owe Tomix an apology!

[serotta1972]

I recently purchased a Tomix 98927 KIHA48 Umineko and compared to the my other trains it was noisy as hell.  Nariichi was kind enough to take it back and even sent it to Tomix and they said it was fine and then sent back to me.  At my end, it was still the same.  After perusing through the forum and if other people had experienced similar problems and learned a few things, actually a lot.  I'm not quite willing to take the thing apart just yet and kept reading on and read something about MRC power packs which I use with their pulse power and how certain Tomix motors react to it and also about the 9 volt test.  Well tonight as I was playing with my trains - I tried the 9 volt test and the damn train ran like a dream!  Holy crap, I feel really bad because I've been quietly ragging on Tomix that they are noisy compared to my Kato trains.  Anyways, does this mean if I get a Tomix controller and power pack - all my Tomix trains will all run quieter.  Am I over simplifying things?

 

I just want to say that this forum is awesome with it's wealth of information and good people  who are really generous with their knowledge.  Thank you so much.

 

With Gratitude,

Junior

[kvp]

It's completly normal for a DC motor designed for high frequency pwm to hum with a low frequency half wave pulse power. You are hearing the line frequency doubled by the rectifier.

 

Powering it with either smooth DC like a Tomytec, Maerklin, Minitrix or Lego wall adapter or battery throttle will be quiet. Using the Tomix CL high frequency pwm will be inaudible.

[ToniBabelony]

An then you have these crazy people who use PWM to imitate real train sounds...

 

 

I want a controller like that, but they don't come cheap!

[kvp]

Cool! Actually this can be done easily with an Arduino based PWM controller... (even the famous Simens traction controller sound)

[ToniBabelony]

Cool! Actually this can be done easily with an Arduino based PWM controller... (even the famous Simens traction controller sound)

I'm very sure it can, but I personally am afraid it'd be too much effort to wrap my head around it with my other model train projects.

[kvp]

Ok, i'll just add it to my Arduino TODO list, it's long enough that one more item doesn't matter... :)

[HantuBlauLOL]

What is the output frequency of MRC power pack? afaik if the power pack has a lower output than 100Hz the motor will generate a weird diesel hydraulic sound, lol.

 

Btw that video is inspiring. I wonder did he use the motor as the speaker or he added a speaker inside the power pack?

 

Also Kvp, can we simulate the real engine sound by knowing the real engine sound frequency and then match the PWM frequency with it?

Edited April 15, 2015 by HantuBlauLOL

[kvp]

Classic pulse power packs cause either 50 or 100 Hz sounds in Europe, 60 or 120 in the US and 50, 60, 100, 120 in Japan depending where you live and the type of the bridge rectifier. (some of them have a shunting option, that halves the frequency by disabling half of the bridge) I have a gaugemaster pulse controller and it generates a diesel sound for everything, but straight wound 3 pole motors are more sensitive to power quiality than others.

The motors can be used as crude speakers, so this is a good way. Otherwise it would be a sound box and the sound wouldn't come from the train. Yes, we can simulate many sounds, for example the Simens inverter has 12 freqency steps with the highest being double of the lowest (it's one octave away). The hungarian V43 has a classic 100 Hz hum thanks to the full bridge rectifier. The ED75 is similar, but 100 or 120 Hz. (they sound just like large blue or red transformers with wheels) Nose hung DC motors (old emu-s) have only the gear and commutator/winding sound, with the straight toothed gear noise being the most characteristic. For diesels, changing the width and frequency of the pulses allows changing the speed and the motor frequency nearly independently of each other.

Also high frequency, low power audio can be mixed onto the traction power and demultiplexed on the train and routed to a piezo speaker. The problem is that this wouldn't be loud enough to be really useful and an audio amplifier would just collect interference from the real motor and cause all TCS equipped head- and taillights to light up.

Edited April 15, 2015 by kvp

[Densha]

serotta1972,

 

I have a Tomix KiHa 40 lying around that probably has the same motor in it as your KiHa 48 does and I have exactly the same problem as you. By 9V test you mean using a 9V battery to run the train? That didn't do the trick for me unfortunately, but I'm glad it did for you. I'm still looking for a solution for mine after two years...

[HantuBlauLOL]

Maybe the motor shaft bent, Densha san..

 

I'm thinking about modifying the PWM controller circuit I sent to you in PM back then, Kvp. The original engineer said even 21KHz is doable.

[Densha]

I don't even know what a motor shaft is, let alone what I would have to do to repair a bent one... :/

Edited April 15, 2015 by Densha

[kvp]

 

I'm thinking about modifying the PWM controller circuit I sent to you in PM back then, Kvp. The original engineer said even 21KHz is doable.

Certainly. Just be avoid driving a DCC decoder equipped train with a really high frequency PWM signal. It tends to burn certain types of decoders...

 

 

I don't even know what a motor shaft is, let alone what I would have to do to repair a bent one... :/

 

The axle of the motor and the mechanical linkage that connects it to the bogies. The small plastic ones thend to brake or bend if the wheels are stopped suddenly when the motor is powered. This usually happens during derailments or in case of sudden reversing. They can be replaced with spare parts when available.

[Densha]

Do you mean the thin black plastic bar connecting the motor and the axle? There's also a spiral-shaped thing above the bogies made of metal that converts the horizontal movement into vertical movement, but I guess that can't break or bend easily. Maybe I'll have to open the model and check it again.

 

It has been like this since I got it in the mail a few years back. It had the problem since the first second I turned on my controller, but sending it back to Japan was a hassle and very expensive.

[HantuBlauLOL]

No, I mean the connection between the main motor and the flywheel (if existed) or the plastic shaft that connected into a spiral metal.

 

Can you hear where did the sound exactly come from? Bogies, or inside the chassis?

[Densha]

By "thin black plastic bar connecting the motor and the axle" I meant that plastic shaft that connected into the spiral metal.

 

Maybe these picture illustrate it better:

 

The point is, it seems to be a electrical problem because I hear an electrical buzz and the lights also flicker. It doesn't seems logical to me that that would be caused by a mechanical problem, or is it?

Edited April 15, 2015 by Densha

[HantuBlauLOL]

Have you tried to connect the motor directly to the power supply? It sounds like a problematic motor.

[serotta1972]

What is the output frequency of MRC power pack? afaik if the power pack has a lower output than 100Hz the motor will generate a weird diesel hydraulic sound, lol.

 

Btw that video is inspiring. I wonder did he use the motor as the speaker or he added a speaker inside the power pack?

 

Also Kvp, can we simulate the real engine sound by knowing the real engine sound frequency and then match the PWM frequency with it?

 

Thanks for the feedback although some of the terminology and technical stuff is a bit over my head.  I have the MRC Tech 2 Loco-motion 1500 - Input 120VAC 60HZ Output 20VDC, 17 VAC, 22VDC Total-12VA - this is what is says on the back of the power pack.  Densha - I think I read through that thread with your ordeal.  Yeah, I powered the track with a 9V battery and the train ran beautifully - hummed around the track.  Any recommendations for a Tomix power pack and controller? I basically just run 2 lines on a hollow door.  

Edited April 16, 2015 by serotta1972

[HantuBlauLOL]

This works like a charm, just need less than 5 bucks and some soldering skill.

 

http://www.rmweb.co.uk/community/index.php?/blog/852/entry-7210-home-brew-handheld-controller-dc/

 

You'll also need a step down trafo to 12VDC though.

Edited April 16, 2015 by HantuBlauLOL

[kvp]

 

This works like a charm, just need less than 5 bucks and some soldering skill.

An buzzes like a charm too. Since it's a pulse power pack.

 

For really smooth DC, i would recommend an LM317 based controller, like the wall adapter (DC only) throttles from Maerklin, Minitrix or Lego (just use a 12V adapter for all of them). But the circuit above will work too if powered from a DC wall adapter or a sufficiently large capacitor is placed across the output of the rectifier bridge. Any Tomix or Tomytec throttle will be good too.

 

ps: That 20V DC output of your pack could be really bad for any N scale trains. Kato ones tolerate it better, but don't like it. That pack is only safe for gauge 0 and 1. I would recommend changing it to a dedicated N scale controller with a maximal output of 12 volts DC.

[serotta1972]

Thanks guys - I'm looking at getting a new one or two and found a thread talking about DC Controllers.  I will look into your suggestions KVP.  And yeah, I never go beyond 50 on the throttle and if I do it's for a short moment.  Man, I just bought a new MRC Tech 7 am pac 780 Dual Control a few months ago for my my V16 set. Oh well.

Edited April 16, 2015 by serotta1972

[HantuBlauLOL]

It's not a pulsed one afaik, I've tested it and it behaves like my Tomix N1 controller.