Hi there,

You need a 0-192V DC power supply. There are a few options on the YourDyno wiki, just search for Eddy brake power supply.

The Telmas are typically 8 or 16 coils, giving either 96V or 192V, but yours may be different?

You don't need to worry about strengths of magnetic fields, etc, just control it with the voltage. The currents and magnetic fields will follow the voltage. 

Cheers,

Thank you for your quick response. 

Yes, I am looking for a 0-192V DC power supply. In my case, the power supply has to ensure at least 192*33.7=6.34kW of power right ?

I guess the retarder I chose is a bit different, its reference is AF83-10. I selected it directly from the Telma website.

Thus, the increasing in voltage is going to produce a higher braking torque. Do you know how could I link these two values.

I mean as a matter of example, if I would like to produce 500Nm of braking torque what would be the voltage needed ?

Thank you again for your very helpful response.

Regard.

Your power calculation is mathematically correct, but are you sure it uses 33.7A at 192V? This is very high, most draw less than 25A at 192V. I did not find any specs for it, so maybe you are right.

JDM Dyno sells power supplies rated for 40A, you can check with him for an off the shelf solution (links in the wiki).

You cannot know what current gives 500Nm. It will vary with RPM and also temperature. So you need some type of feedback.

Yes I am sure of the 33.7A. I will try tomorrow to post the electrical requirements sent by Telma in order to show you.

I am going to take a look at the JDM Dyno product.

It's embarassing, I thought there was an easy relation between the voltage/intensity and braking torque.

For instance, to perform a test, the basic procedure would be to start from 0V and go through the full range of voltage until 192V ? And I guess the maximum braking effect would be obtained at the maximum voltage ? Is that right ?

This is an extract of the electrical specifications that Telma sent me 

OK, that was a clear spec, so correct then!

To do a controlled sweep you need a controller with a regulator, typically a PID regulator, that uses RPM as input and Brake control voltage as output. You can do this with YourDyno :-). 

It will typically not be 0-192V because most of the time you don't need to use the full power of the brake. Also the brake has a torque curve vs RPM, so you need some active regulator to get a smooth sweep. 

If your setup has enough Moment of inertia, then you can use a fixed voltage and still get a sweep. You need to chose a voltage that gives a lower torque than the engine has at each RPM. The engine will then sweep through the RPM range, and the sweep rate will change along the sweep, set by brake torque curve (for the chosen voltage ), the engine torque curve, and the moment of inertia. Possible... You still need a DAQ to read the RPM and load and power from the acceleration and MOI. A YourDyno controller is low cost in comparison to the rest of the system, so well worth it :-)! 

Hi Totally_Dyno_Beginner , welcome to the forum

You realise you will not be applying full voltage to totally stop the engine totally ! By the way what engines are you planning on testing?

My goal is very simple : I want to reproduce the road steepness onto a roller test bench.

Since I know the testing vehicule's weight, I computed the required torque that I have to apply to brake (and then simulate the slope).

I dont need to chart any curve, nor load cell or software. 

Flat surface coasting down a freeway at 100km/h with no head wind a fairly aerodynamic little 1100kilogram weight vehicle in 5th gear overdrive engine revving at say between 1800 to 2100rpm  how much kilowatts ( throttle % opening ) will the engine have produce to maintain  a constant steady speed of 100km/hroughly ? ( lets ignore other variables factirs into the equation)

Now increase the surface incline from zero degrees to 45 degrees ( steepness) and repeat  the 100km/h speed process again ? Is that what I'm understanding you just want to do ??? Only going via one of you stated comments at the very 1st post ?

With a load cell and speed sensor at your finger tips you won't have to " computed the required torque "  as you can see it on a computer screen with the aid of your dyno  , i won't go into any further explanation. 

Just use a car differential to do the
ratio speed multiplication required

SStill don't know if you're building
a chassis dyno , engine dyno ,
"roller test bench" benchtop lab dyno ?

Just buy yourdyno blue box controller as admin suggest you wont go wrong and get Semikron SKPC 200 phase angle controller

https://yourdyno.com/YourDynoHelp/eddy-current-brake-control/

Disregard  the part " Just use a car differential to do the ratio speed multiplication required" sorry  think elsewhere  post!

Posted by: @mach_1

You realise you will not be applying full voltage to totally stop the engine totally ! By the way what engines are you planning on testing?

Flat surface coasting down a freeway at 100km/h with no head wind a fairly aerodynamic little 1100kilogram weight vehicle in 5th gear overdrive engine revving at say between 1800 to 2100rpm  how much kilowatts ( throttle % opening ) will the engine have produce to maintain  a constant steady speed of 100km/hroughly ? ( lets ignore other variables factirs into the equation)

SStill don't know if you're building
a chassis dyno , engine dyno ,
"roller test bench" benchtop lab dyno ?

I am building a roller test bench in order to test several railway vehicules. They are heavier and go slower than your example. The maximum weight is around 5000kg and the max speed is 35km/h. They are equipped with hydraulic engines.

I would like to show you pictures but I can not say much about it unfortunatly due to confidentiality. 

Your description is almost right : I want to know if the vehicule is able to go through a 2 degree slope while maintaining its constant speed (30km/h).

To do so, the engines have to create more torque to overcome the slope. And, I wanted the Telma braking torque play the role of the torque generated by the slope. 

I previously calculated the torque generated by the slope for each vehicule, that is the reason why I wanted to link voltage and braking torque (e.g. To create a 500 Nm braking torque, I have to adjust a certain value of voltage on the power supplier). Admin told me that is was better to perform a sweep test.

Thanks for your help, I know my project is a bit singular compared to what you are used to. 😓 

Cheers,

Ok gotcha  now if i understood you right , you want to stimulate tests without actaully putting the train cart on  the dyno?

simulated ooops not stimulate! Sorry

I do want to put the train cart on the dyno otherwise I can not test anything.

The roller test bench allows be to test a rail vehicule without testing it on real railway. 

Sorry for my lack of clarity, I feel like I confused you.

Are these train carts wheels steel ? Steel on rail track steel ? ( steel driven on steel surface )

Yes, train carts wheels are galvanised steel and painted.

The rollers are pure steel (no treatment added on the surface).