DIY Dyno

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gerad
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DIY Dyno

Post by gerad »

It is someone interested in a DIY Dyno ?
so far
custom board with :
ft232rl ( usb-serial )
atmega328 (arduino firmware)
mcp3208 (12bit adc )
mpxh6400 ( 4 bar map )
2x ina125 ( load cell amp )
2x rpm ( engine and roller )
2X 0-5 wb02 imput
2x egt
1x 12 bit optional input
4x opto out ( driving brake and misc )
weather station ( hih humidity senzor , lm35 temp senzor , mpx 4250 ).
software : working spi , sending string , labview bazic app

i will post some photos .
to do : software side ( if you can help only on stm32 platform , i can make the hardware )
The project will be open source .

egt test
gerad
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Re: DIY Dyno

Post by gerad »

The schematic and pcb are in eagle ... and software is labview ( i am noob at code .... and it is just for test the hardware . far from working software).
Tanks in advance for your ideas / support / test
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AndreyB
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Re: DIY Dyno

Post by AndreyB »

What kind of drums do you see used with this? I mean - what about the dyno itself?
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gerad
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Re: DIY Dyno

Post by gerad »

Home made rolls (4x 900 mm - 218mm diameter ) for 2wd , EDDY brake from volvo truck , 24v 100 amp big russian battery charger ( from a ship :)) ) , igbt module . I will make some photos on the rolls , brake , bearings . ( i need just 2 big steel profiles .... and.... work )
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EDDY brake from volvo truck
EDDY brake from volvo truck
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puff
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Re: DIY Dyno

Post by puff »

занятная тема!
как это будет калиброваться и в каком регионе базироваться?
gerad
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Re: DIY Dyno

Post by gerad »

puff : entertaining theme! as it will be calibrated and in what region based?
Tanki! U menya yest 'kh 2 250 kg tenzodatchik i kalibrovka nikh. Tork yavlyayetsya sleduyushchim rychag (1m dlya teoreticheskogo nm / m).
Region: zamedlitel 'yavlyayetsya 1000nm +. YA iz Rumynii (yesli eto oblast 'vy imeyete v vidu)

tanks ! I have 2 x 250 kg load cell , i will calibrate them . next is the tork arm ( teoretical 1m for nm/m ) .
region : the retarder is 1000nm + . I am from romania ( if this is the region you mean )

* google translate

the design is based on gladiator dyno +/-
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kb1gtt
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Re: DIY Dyno

Post by kb1gtt »

Labview is kind of expensive piece of the puzzle, which would make this very hard for most DIY folks. Perhaps http://www.myopenlab.de/startseite/screenshots.html would help make this more obtainable for the DIY folks. Perhaps http://www.scilab.org/resources/documentation/tutorials could be used instead.

I suspect you are looking at LabView because it simplifies the software, so perhaps long term a Java program similar to the devconsole would be a good approach.

Do you have more details on the EDDY brakes? I'm sure the 2400 Watts of DC power is some how operating the brakes as most vehicles would generate far more than that. I see this reasonably low cost power supply that does 40A at 24V for $265 http://www.automationdirect.com/adc/Shopping/Catalog/Power_Products_(Electrical)/DC_Power_Supplies/24VDC,_3-Phase_Input/PSB24-960S-3 I wonder what's needed for the truck brakes to be operated, and why a more normal braking system can't be used. The cost of the power supply might make it lower cost to use a compressor and pneumatic valve.

I'm not seeing the big picture here. I think you are planning to dump the wheel energy into the brakes, but how do you measure the energy? I suspect you are planning for something like controlling 24V current to the brakes such that say 20A = ?? kW of energy. However as brakes warm up I would expect that ??kW to be ??kW - ??kW. There is also a lot of dynamic math as much of the energy is dumped into the inertia of the system. Do you plan to add a large mass to help absorb the energy and decrease the load on the brakes? I think you are planning for something like this http://jalopnik.com/5807502/how-to-build-your-own-dyno-for-just-2000/ which has relatively low inertia.

About Design, I would suggest looking at Frankenso's PCB. It uses MAX31855KASA which saves a bunch of analog interfacing, as well it has most of the physical pieces you have on your board.

About 100A, I believe you intend to PWM control that with some kind of chip. Perhaps something like this http://www.newark.com/infineon/dcmotorcontrbtn8982tobo1/evaluation-board-btn8982-dc-motor/dp/93X8231?CMP=AFC-OP?gross_price=

Do you have a truck axle to work with yet? Do you have that additional electromagnetic brake? I don't see how that system can measure the kW's it's absorbing, I think it's only good for relative variations.
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gerad
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Re: DIY Dyno

Post by gerad »

The retarder take 24v at ~ 100 amp (2.4kw ) and can brake 1000 nm ( ~ 1000 hp ~ 760 kw ) can be easly rewire for 192v and use rezistor + triac (?!) for 220v but i have the power supplay alreddy ( it is a big an bulky psu ~ 40 kg ) so ... i use like it is . I use labview becouse is the single thing i can understand . if somewoane is willing to do a java app it will be gold for many of efi fan.
i will use a igbt driven by opto to power the retarder , the kw is calculated by nm and rpm , nm = nwton /m .
MAX31855KASA .... no because i use mcp3208 ( 12 bit ) for the ina125 ( load cell amp) to have more rezolution for power .
the control part : fixed load , or rpm / speed lock ( block rpm at 2000 rpm , tune all points then ... 2500 .... )

some good info to understand better :
gerad
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Re: DIY Dyno

Post by gerad »

the arduino code :
serial comands :
1 - light a led ( test)
2 - light a led ( test)
3 - sends temp , kpa , rh ( weader station )
? - mcp adc ? adc1 , adc2 ... , adc8 , rpm , roller rpm ,



need to do : implement rpm and drum rpm ( on int0 and int1 ) , and pid for load control ( rpm or speed setpoint )
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kb1gtt
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Re: DIY Dyno

Post by kb1gtt »

Do I understand the design to be an electronic controlled brake connected with a lever arm and force sensor, such that you can vary the power being absorbed by the brake which will vary the torque on the lever arm, which you can then measure with a force gauge? Then display the measured torque or apply RPM for HP and display it some how? I don't recall talk of the pressure sensor, so I wonder if that's some how obtained from the eddy current device.

Do you have a make / model number or datasheet for the eddy current device?

Pressure sensors are reasonably low cost. This one is a 1000kg (2200 lb) cell for $45 on ebay.

http://www.ebay.com/itm/S-TYPE-Beam-Load-Cell-Scale-Sensor-Weighting-Sensor-1000kg-22CWT-With-Cable-/181778421153?hash=item2a52d695a1

If it's a lever arm system, why not use many small drum brakes off low cost trucks and the electronic brake pump off an ABS module to control the brakes. That would surely be a fraction of the cost of that eddy device and 100A power supply.
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gerad
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Re: DIY Dyno

Post by gerad »

kb1gtt yes , i dont have a datasheet but some general info http://telmausa.com/TELMATECHWEB/DOC/PDF/TL101009.pdf , the load cell i have are from digital scale for market ( aluminium 250 kg ~ 2500 n ) one is new one is .... but good . I can not use brakes for absorbing the power .. after ~ 30 sec of load it will be hot .... after ~ 1 hour i think you will change the pads ..... ~4 hours change the disks .
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kb1gtt
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Re: DIY Dyno

Post by kb1gtt »

Got it, mechanical friction wears out in short order. These eddy devices have much better longevity. It seems these eddy brakes are significantly expensive, in the $1k and above range. Perhaps you can get lucky at a salvage yard, but that's going to be a limited supply and with inconsistent results. I wonder if an eddy brake could be made with the help of software like this http://www.femm.info/wiki/HomePage Specifically this looks interesting http://www.femm.info/wiki/EddyCurrentBrake

Using at least partly a permanent magnet could also help ease the 100A thing.

I wonder if a transmission torque converter could make a good brake device. Those are fairly easier to get and far lower cost than these eddy brakes. I suspect a significant part of the cost of these brakes is that they are a life safety system, while a torque converter is not life safety. Perhaps a lower cost version could be done by using a transmission torque converter.
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gerad
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Re: DIY Dyno

Post by gerad »

Nice software . i have made a few years ago , a little eddy brake before i buy the big one . I dont think is a good ideea with tork convertor but you can use a oil pump from a hidraulic sistem . ( work well but you need a lot of oil for heat excange )
KLAS
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Re: DIY Dyno

Post by KLAS »

kb1gtt wrote:I wonder if a transmission torque converter could make a good brake device.
there are some people around that do just that, using it like a water brake as used with hydraulic engine dynos.
thats why i once bought one, but never found the time to build.
gerad
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Re: DIY Dyno

Post by gerad »

And the heat goes to ... ? from the convertor ...
more pictures : - psu = russian psu with 12v , 24v 100+ amp , 48v 60 amp
- drums are home made
- load cell
- unfinished little eddy brake
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kb1gtt
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Re: DIY Dyno

Post by kb1gtt »

Nice pictures. How long is your lever arm? Wouldn't you need a long lever arm if you are using the 250kg cell? I guess some math would be helpful in showing the min and max expected forces.

Heat from the torque converter would go to a radiator just like in your car. Radiator could potentially be mounted outside the building, which could be nice on hot summer days. I see a key issue with a re-purposed torque converter being the RPM at which they start to engage. As well you may need to bypass the lock up clutch.

Yes used like a water brake dyno https://en.wikipedia.org/wiki/Water_brake I've only seen water brakes in the 20HP range.
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gerad
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Re: DIY Dyno

Post by gerad »

i know about water brake ( same problem ... heat .. you need water source for good operation ) , on 300kw oil pump the oil wil be too hot in max 5 min ( ~ 50 l ). For low load you can use : steering pump ( about 15 hp ) , alternator ( use rezistor on AC side in delta ) and you can controll the load via charce curent .The level arm it will be 50cm so 1250 max nm on one cell.
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kb1gtt
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Re: DIY Dyno

Post by kb1gtt »

You need to dump around 400kW to 800kW (500HP to 1kHP) some where as heat. That's a significant amount of heat to deal with.
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Re: DIY Dyno

Post by puff »

what about connecting it to the power grid? large HVAC system? water boiler?
gerad
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Re: DIY Dyno

Post by gerad »

You need to dump around 400kW to 800kW (500HP to 1kHP) some where as heat. That's a significant amount of heat to deal with. ------- Thats why i chose eddy brake ... you need to put little power to brake alot and it does not heat up ( on our aplication ).


what about connecting it to the power grid? large HVAC system? water boiler? ------ put a generator and power 50 houses , or make heat ( from water brake ) to heat maybe 10 houses :))) * joke
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Re: DIY Dyno

Post by KLAS »

maybe a good overview what kind of dyno may be best for someones use http://www.dynomitedynamometer.com/dynamometer/dynamometer-comparison.htm

each type of dyno has it's advantages and disadvantages
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kb1gtt
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Re: DIY Dyno

Post by kb1gtt »

According to that chart,

Water Brake has 10 Excellent marks
Air cool eddy has 2 Excellent marks
Water cooled eddy has 5 Excellent marks
AC motor has 1 Excellant mark.

After trimming down the rows that I figured most people would care about, it looked like it was a toss up between water brake and liquid cooled eddy. However comparing all rows would lead you to believe that liquid cooled eddy brake and eddy brakes are sub par. I then figured this company was pushing water brake tech, so I went though their selector tool and ended up at this page http://www.dynomitedynamometer.com/chassis-dyno/chassis-dyno-price.htm

They had 7 water brake 2WD options. Then for 4WD they had one option to upgrade to water brake. I also see this note about water brake.
Water brake power capacities are RPM dependent and assume a minimum water supply of 1 gpm @ 30 psi for every 20 continuous Hp.

So 2kHp would require 100GPM, which is significant water flow and would be hard for most people to get.

They have 42 eddy technologies listed on that pre-configured page. So it would appear they push the eddy current design, but claim water brake is better technology if you have the water to work with.
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kb1gtt
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Re: DIY Dyno

Post by kb1gtt »

What materiel is that eddy brake made of? According to the below PDF it is likely it's made mostly of aluminium. Does it have permanent magnets inside?

http://deepblue.lib.umich.edu/bitstream/handle/2027.42/109373/me450w10project16_report.pdf?sequence=1

Also this link may be of interest. I would suggest considering the 1X 60" diameter roller instead of 2X 8.5 diameter rollers.

http://www.dynomitedynamometer.com/dyno-tech-talk/roll_diameter.htm
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gerad
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Re: DIY Dyno

Post by gerad »

The disks of the retarder are of cast iron ; the "magnets" are the coils .....
diyefi
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Re: DIY Dyno

Post by diyefi »

gerad wrote:
Sat Aug 15, 2015 12:56 pm
It is someone interested in a DIY Dyno ?
so far
custom board with :
ft232rl ( usb-serial )
atmega328 (arduino firmware)
mcp3208 (12bit adc )
mpxh6400 ( 4 bar map )
2x ina125 ( load cell amp )
2x rpm ( engine and roller )
2X 0-5 wb02 imput
2x egt
1x 12 bit optional input
4x opto out ( driving brake and misc )
weather station ( hih humidity senzor , lm35 temp senzor , mpx 4250 ).
software : working spi , sending string , labview bazic app

i will post some photos .
to do : software side ( if you can help only on stm32 platform , i can make the hardware )
The project will be open source .

egt test
hello, Can you please send Simpledyno program, thank you
jverban@hotmail.com
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