@admin

Hello

I am running a test setup with 40cc pump and AC motor.  The valve is controlled manualy at the moment.

I am looking how to connect the TB6600 green driver board to the blue box. It has the following connections: +5V, CLK-, CW-, EN-

The same boards is usen for my CNC where it work OK. the used connections are only +5V, CLK-, CW-

CLK-, CW- I can connect to blue box, what about +5V?

TB6600 bottom

Cheers

Hi, you have 9700 steps between 0 and full brake? That's a lot! With 2000 steps per sec, then it takes about 5 sec from 0 to full brake, that's too slow. 

Have you turned on micro stepping, if so turn it off. Otherwise, the only solution is to gear it or change the valve.

Posted by: eric91

Posted by: admin

I agree, but just to let you know the Brake sweep should also be good for your setup, and easier to find the best settings for. 

Very good, Im eager to try it! Do you have make a video to explain how sweep brake works? 

Hello Eric could you send me photos of your Dyno to my email? pepetruenomejia@hotmail.com 

Posted by: admin

I agree, but just to let you know the Brake sweep should also be good for your setup, and easier to find the best settings for. 

Very good, Im eager to try it! Do you have make a video to explain how sweep brake works? 

I agree, but just to let you know the Brake sweep should also be good for your setup, and easier to find the best settings for. 

Hi Jostein, now I'm still working for improve hardware setup, when it will be finish (I hope very soon) I will try brake sweep, but I think that with correct size pump the dyno must work also without sweep brake. 

Hi Eric, for the hydraulic brake you should try the Brake sweep. Start at for example 6000RPM,  then set for example 5 to 10% brake rate, keep start rpm for say 2 sec.

Hi guys, some updates of my hydraulic brake with 70cc gear pump and new chassis with 2 ucp 210 bearings for shaft and 2 ucp 209 bearings for pump. 

Other update is the motor support sled that now is hold at chassis by rubber's anti-vibration support. 

hi   Eric

thank you for your information

from 30cc to 70cc more than double your pump ,   i think you will be correct

i will test snowmobile engine

Hi stepper dyno, Im just rebuilding the brake with 70cc pump instead of 30cc pump that Ii too small for My kart 125 Engine. After some tests, I have also broken the pump's bearing.

In My setup I use nema 34 stepper engine that has about 7Nm of torque. I have add also 0.5 Gear ratio, I think it's useful also for your setup. What kind of engine you will test? 

hi

thank you Jostein for your fast reply

my dyno is not completed  , i ask questions before i buy your dyno system , i have 2 valve if i need to...

i think the max in your software is 2000 steps/ sec  and if i need faster valve to open and closed i will need to have a reduction

like 2 to 1 or 3 to 1  like you tell me  , if i reduce my stepper motor to turn the valve faster i will drop in torque ...its my question about the need of a big stepper motor ?  my valve can be hard to open and close with the pressure and  i also think that my valve will not be 100 % linear...,  full open to full close is 7 turn

with 200 steps per turn its 1400 step

i also have a safety bypass valve that can open over 3000 psi and can flow 30 gal min , 120l min to not shock the system

i dont need very fast ramp run  , just some good steady state rpm to map fuel table and timing with out to much oscilation

or big rpm variation , and with your closed loop pid system i will not have to chase rpm manually if it drift..

thanks

Hi,

A few things to think about here:

• The control from min to max valve opening needs to be very fast, so do calculate the number of steps you need and max steps per sec (maybe 2000 steps/sec), and note that you need to include acceleration (maybe 5000 steps/sec^2). You may need gearing if it is not fast enough (at least sub 0.5 sec, preferably faster)
• 100% brake must NOT equal valve completely closed, or you will very abruptly stop the engine, even if the valve goes to 100% for just a fraction of a second. Adjust the min and max brake in software to avoid this.
• The valve should ideally provide a linear brake response. By that I mean if 25% brake gives you X newton meters of braking force, 50% brake should give 2X Nm braking force. This is not necessarily the case for your valve. If you don't achieve this, then the optimum PID parameters will not be the same for all valve openings, which means you will have to go for a conservative (= slow response) setting. You should take a look at flow vs valve opening at a fixed pressure for example, see if your valve is fairly linear. 

I was working with Eric over Facebook Messenger and we got the system to be very stable at 6000RPM, but it did not work well at 10000 RPM and above. It was also not stable on manual control at high RPMs. After some investigations it was found that the pump was way too small, and it could not cope with the high horsepower at higher RPMs. He is rebuilding with another pump.

Cheers,
Jostein

the pump

https://www.lifcohydraulics.com/pdfs/Tyrone-(FPDV25)-Dry-Valve-Pumps.pdf

hi 

i am building a hydraulic dyno with a big pump - tyrone fpdv550  181.24 cc rev , i have this valve ffg2008ta  http://seawayfluidpowergroup.com/wp-content/themes/seawayfluidpowergroup/uploads/needle-valve-series.pdf

for a stepper motor is it better for me a nema 42  than a 34...?    i can have 10-20-or 30 nm ,1000 to 4000 oz-in

like this...?  https://www.automationtechnologiesinc.com/products-page/nema-42/nema42-stepper-motor-3256/

https://www.automationtechnologiesinc.com/products-page/kl-stepper-drivers/kl-11080-stepper-drive/

what do you think ?    i fear to not have enuff torque with a to small stepper choice  to turn my big valve and have very good

steady state rpm control with the pid

and Eric do you have some news...  or good control of your system ?

thanks