1LikesEagle Racing MD2 Motor Dyno
09-02-2015, 05:15 PM
#31
Since these dyno's are dwindling in stock. I've come across a batch of dyno's with 30 amp fuses installed. During a small QC check and test the dyno's with 30 amp fuses worked fine. I would highly suggest those who are receiving theirs MD2 dynos (soon) to switch over to 35 amp fuses.
09-02-2015, 06:50 PM
#32
hprt that is excellent information great explanation thank you.
BobW thanks for posting the drawing I will have to try one.
A further note on the dyno and consistency.
When running in brushed mode the consistency is very high but in brushless mode the consistency varies depending on the ESC used.
The best ESC I have used with the dyno is the LRP sphere. With this ESC I was able to make small adjustments to timing and rotor position and see the change in power output.
With the x car ESC the output varied a lot from run to run which whilst it was a cheap ESC I did not find the ESC helpful in tuning the motor. (perhaps the x car ESC with HW software loaded will work better?)
By finding the timing sweat spot and optimizing the rotor and sensor position I managed to gain 5% more power with several motors which has been noticeable on the track.
BobW thanks for posting the drawing I will have to try one.
A further note on the dyno and consistency.
When running in brushed mode the consistency is very high but in brushless mode the consistency varies depending on the ESC used.
The best ESC I have used with the dyno is the LRP sphere. With this ESC I was able to make small adjustments to timing and rotor position and see the change in power output.
With the x car ESC the output varied a lot from run to run which whilst it was a cheap ESC I did not find the ESC helpful in tuning the motor. (perhaps the x car ESC with HW software loaded will work better?)
By finding the timing sweat spot and optimizing the rotor and sensor position I managed to gain 5% more power with several motors which has been noticeable on the track.
To the point that in certain circumstances, I was getting what appeared to be current limiting going on but what I believe to be the ESC taking 200ms to reach full output. This gives weird results when plotted, as the peak torque doesn't arrive until 8 or 9000 rpm, which I know is wrong. These are also sensorless motor/ESC combos, and I have tested several of the same motor/ESC type with the same result - so it is inherent to the combination.
you can see this in the two attachments - one is a 17.5 D4 with a Novak Edge ESC, the second is an Orca Spark ESC and 2200kv sensorless combo (we use for Mini). Note the delay in peak current draw with the Orca - almost 250ms after the run starts, where as the Edge ESC is at full output in under 40ms.
What does this mean? Not sure yet. All I do know is that if you are comparing motors, definitely use the same ESC.
09-02-2015, 07:55 PM
#34
I have noticed that not all ESC's behave the same on this dyno.
To the point that in certain circumstances, I was getting what appeared to be current limiting going on but what I believe to be the ESC taking 200ms to reach full output. This gives weird results when plotted, as the peak torque doesn't arrive until 8 or 9000 rpm, which I know is wrong. These are also sensorless motor/ESC combos, and I have tested several of the same motor/ESC type with the same result - so it is inherent to the combination.
you can see this in the two attachments - one is a 17.5 D4 with a Novak Edge ESC, the second is an Orca Spark ESC and 2200kv sensorless combo (we use for Mini). Note the delay in peak current draw with the Orca - almost 250ms after the run starts, where as the Edge ESC is at full output in under 40ms.
What does this mean? Not sure yet. All I do know is that if you are comparing motors, definitely use the same ESC.
To the point that in certain circumstances, I was getting what appeared to be current limiting going on but what I believe to be the ESC taking 200ms to reach full output. This gives weird results when plotted, as the peak torque doesn't arrive until 8 or 9000 rpm, which I know is wrong. These are also sensorless motor/ESC combos, and I have tested several of the same motor/ESC type with the same result - so it is inherent to the combination.
you can see this in the two attachments - one is a 17.5 D4 with a Novak Edge ESC, the second is an Orca Spark ESC and 2200kv sensorless combo (we use for Mini). Note the delay in peak current draw with the Orca - almost 250ms after the run starts, where as the Edge ESC is at full output in under 40ms.
What does this mean? Not sure yet. All I do know is that if you are comparing motors, definitely use the same ESC.
The sensorless output is very strange. It's like the ESC can't figure out what to do. Current certainly shouldn't peak mid way through the run. Never run sensorless motors but I would expect performance to be similar to sensored. One thing for sure that motor would really suck on track.
09-02-2015, 08:21 PM
#35
That doesn't surprise me at all. Sensorless speedos need a bit of time to figure out exactly where the rotor is, especially cheap ones. That's why we use sensors, they pretty much always know where the rotor is.
09-02-2015, 08:32 PM
#36
Tech Regular
iTrader: (5)
I though at first there was current limiting going on with some ESCs but I now have another theory that I need to test which I was hoping a larger flywheel would help.
That motor/ESC is a bit odd but as per wingracer comment sensorless can be a bit inconsistent at slow speed due to the esc working out the rotor position. I doubt it matters in a mini as you probably cant put all the power down through the front wheels.
That motor/ESC is a bit odd but as per wingracer comment sensorless can be a bit inconsistent at slow speed due to the esc working out the rotor position. I doubt it matters in a mini as you probably cant put all the power down through the front wheels.
09-03-2015, 04:15 AM
#37
Many ESCs have a limit on their spool-up time. It's a simple way to reduce the possibility of high current at low speeds (to protect the MOSFETs) since it requires only software. On some ESCs the spool-up time is adjustable with a parameter called "punch rate" (or something similar). Low rates-- long spool-up times-- can improve driveability in low-traction conditions.
Needless to say, you'll want to use the maximum rate, or minimum time, during dyno testing, and throw out the results where it is in play.
As wingracer stated, there should be no confusion on rotor position with a sensored ESC. Unsensored ESCs are poor choices for dyno use.
Needless to say, you'll want to use the maximum rate, or minimum time, during dyno testing, and throw out the results where it is in play.
As wingracer stated, there should be no confusion on rotor position with a sensored ESC. Unsensored ESCs are poor choices for dyno use.
09-03-2015, 08:31 AM
#40
Many ESCs have a limit on their spool-up time. It's a simple way to reduce the possibility of high current at low speeds (to protect the MOSFETs) since it requires only software. On some ESCs the spool-up time is adjustable with a parameter called "punch rate" (or something similar). Low rates-- long spool-up times-- can improve driveability in low-traction conditions.
Needless to say, you'll want to use the maximum rate, or minimum time, during dyno testing, and throw out the results where it is in play.
As wingracer stated, there should be no confusion on rotor position with a sensored ESC. Unsensored ESCs are poor choices for dyno use.
Needless to say, you'll want to use the maximum rate, or minimum time, during dyno testing, and throw out the results where it is in play.
As wingracer stated, there should be no confusion on rotor position with a sensored ESC. Unsensored ESCs are poor choices for dyno use.
I found that to stay consistent with all my dyno numbers I use a older pre-timing type speed control, taking that variant out of the equation. JMO
09-03-2015, 08:35 AM
#41
Interesting thing happened the other night.
I use the Sky RC motor checker to determine the actual timing on the motor before I run it on the MD2 dyno.
A couple of nights ago, I got lazy and just connected the alligator clips to the motor while still connected to the esc and the dyno. While running the timing test, it popped the cap on the ESC. Woke me up - that's for sure. This was on a Tekin RS. No other damage, just a vaporized cap.
Anyone else had any issues like this?
I use the Sky RC motor checker to determine the actual timing on the motor before I run it on the MD2 dyno.
A couple of nights ago, I got lazy and just connected the alligator clips to the motor while still connected to the esc and the dyno. While running the timing test, it popped the cap on the ESC. Woke me up - that's for sure. This was on a Tekin RS. No other damage, just a vaporized cap.
Anyone else had any issues like this?
09-03-2015, 08:37 AM
#42
09-03-2015, 08:38 AM
#43
Interesting thing happened the other night.
I use the Sky RC motor checker to determine the actual timing on the motor before I run it on the MD2 dyno.
A couple of nights ago, I got lazy and just connected the alligator clips to the motor while still connected to the esc and the dyno. While running the timing test, it popped the cap on the ESC. Woke me up - that's for sure. This was on a Tekin RS. No other damage, just a vaporized cap.
Anyone else had any issues like this?
I use the Sky RC motor checker to determine the actual timing on the motor before I run it on the MD2 dyno.
A couple of nights ago, I got lazy and just connected the alligator clips to the motor while still connected to the esc and the dyno. While running the timing test, it popped the cap on the ESC. Woke me up - that's for sure. This was on a Tekin RS. No other damage, just a vaporized cap.
Anyone else had any issues like this?
Once I have it hard wired, I move the "octopuss" between all three units. I do remove the flywheel though when timing test is done.