Dyno, Homemade, Using a Novak Sentry Data Logger, Continued, The Experimental Thread.
#196
Tech Elite
iTrader: (37)
have you tested a 21.5 with a 2s lipo? were buildin a chassis/ motor dyno with the sentry. and i just finished reading all the info posted in the last 13 pages and all i can sey is wow. thats alot of info to look at in all.
were planning on using alumimum disks and neo magnets to simulate resistance. (lenz LAW)
it increases resistance as rpm increases. so it should be a good start point.
with no friction .
were planning on using alumimum disks and neo magnets to simulate resistance. (lenz LAW)
it increases resistance as rpm increases. so it should be a good start point.
with no friction .
#197
Tech Adept
I'm not sure what you're trying to accomplish with a magnetic brake, some kind of controlled load simulation?
In the control system industry there are many kinds of brakes available for building assembly lines and factory machines. If load control is required for small systems an electrically modulated magnetic brake is one solution.
Here is a magnetic brake used on airplanes from a 9V battery for on/off braking, but something like this could be used for controlled braking if properly designed and rated for use with the Sentry Dyno.
http://www.hobby-lobby.com/wheels.htmBrake.htm
In the control system industry there are many kinds of brakes available for building assembly lines and factory machines. If load control is required for small systems an electrically modulated magnetic brake is one solution.
Here is a magnetic brake used on airplanes from a 9V battery for on/off braking, but something like this could be used for controlled braking if properly designed and rated for use with the Sentry Dyno.
http://www.hobby-lobby.com/wheels.htmBrake.htm
#199
Tech Adept
What do you intend to accomplish in terms of test and measurement using a light flywheel and fixed torque brake? That part is not clear ...
#200
Tech Adept
On real dyno's the use the eddy current brake to hold a specific RPM and load. that way you can monitor at steady state instead of always changing conditions like a simple inertial dyno. Probably of more use for IC engines where you need to adjust AF and spark for load and RPM.
john
john
#201
With the newer speedo's some things are adjusted on a time delay. Because of this a transient measurement is actually more useful at the moment.
Rather than using an eddy current brake set-up you might want to look at building a flywheel that has adjustable weight. Full scale this is normally some extra disc sections that are pinned to the main flywheel.
Best case is to match the acceleration of the flywheel to how the car performs on the track. Normally less weight for small tracks and more weight for big tracks.
Rather than using an eddy current brake set-up you might want to look at building a flywheel that has adjustable weight. Full scale this is normally some extra disc sections that are pinned to the main flywheel.
Best case is to match the acceleration of the flywheel to how the car performs on the track. Normally less weight for small tracks and more weight for big tracks.
#202
Tech Adept
The main use I see for a brake is to measure current draw at a simulated load condition. For example, someone here was trying to simulate current draw at top speed on the Velodrome using an old brush motor in generator mode with a high power resistor to simulate a steady load. The problem then becomes setting the right value of the load which is a function of actual friction in the driveline and air drag. However, ballpark measurements are sometimes useful too.
The only problem I see with tuning for peak power on a flywheel dyno is that, in some systems, more power translates to less on track performance, since in a "fuel efficiency" race it may be more important to stay high on the battery curve near the end to avoid power fade. This was more critical with NiMH because the internal resistance climbs more rapidly than with LiPO, as far as I can tell from some data posted around the web.
The only problem I see with tuning for peak power on a flywheel dyno is that, in some systems, more power translates to less on track performance, since in a "fuel efficiency" race it may be more important to stay high on the battery curve near the end to avoid power fade. This was more critical with NiMH because the internal resistance climbs more rapidly than with LiPO, as far as I can tell from some data posted around the web.
#203
Tech Adept
I'm bumping this thread and posting an excellent four page discussion of the problems inherent in taking analog-to-digital measurements using a PC oscilloscope to measure nerve signals. The same principles apply to using a data acquisition module in general:
http://www.funjournal.org/downloads/GeorgeJUNEf06.pdf
http://www.funjournal.org/downloads/GeorgeJUNEf06.pdf
#204
Tech Addict
could someone upload some more engine vs engine power figures please.
if you have.
if you have.
#205
Tech Fanatic
iTrader: (11)
Hey guys, Ive found this thread and found it quite interesting lots of information. A lot of the info is for using flywheel dynos, but would it be useful to have or make some kind of dyno used for real cars, the ones you would sit the car on spinning wheels/pulleys such as something similar to the pic attached, using the Novak sentry data logger information to get readings, would this be usefull or accurate or has anybody made such a similar type??
#207
Tech Addict
Kw = (Nm*RPM)/9550
If you got the power and rpm torque is easy.
sounds weird to only know the max power and not knowing the rpm or torque.
If you got the power and rpm torque is easy.
sounds weird to only know the max power and not knowing the rpm or torque.
#208
We're using the electric power in and the mechanical power out to show efficiency.
#209
Tech Rookie
Is this what you mean?
would it be useful to have or make some kind of dyno used for real cars, the ones you would sit the car on spinning wheels/pulleys
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