[Hank80]

Over the weekend I was able to use an Intergy Battery charger/motor Dyno that we use in our R/C racing.

I am able to adjust the run votlage from 1 to 9 volts. I set the run voltage at 7.5 volts and placed the sensor on a shaft from a scalextric motor and place this motor into the side of the Dyno and ran it. I was reading around 8,000 rpm.

Now with the voltage set at half what we race on. Which is 15 volts. If I where to just multiply by 2 would that be an accurate reading for the total rpm? Or do I need to do something in addition to this?

I was thinking that 8,000 x 2 = 16,000 @ 15 volts? Correct or is something missing?

Thanks in advance
Henry :wave:

 

[PD2]

Nah, I'd say that is not an accurate indicator mainly because you do not know what the characteristics of the motor will be once you start putting more voltage to it. Think about R/C - springs, brushes, etc. - they all do different things when brough up to the full voltage. Same thing here - one motor will give you more torque or peak out differently once you push it to its full voltage. I'd say that its not very accurate and you would need to capture more voltage. That may be a good general indicator or nice round or broad area you could use, but definitely not accurate enough to know what hides behind the motor once pegged out.

PD2

 

[Hank80]

Thanks PD2,

I am looking into see if the power to run the motor can be increased to 14 to 18 volts. The manufacturer of the charger is suppose to get back in touch. But right now its a general indicator like you said. I'll let you know what happens over the next few days and weeks,.....

Thanks
Henry

 

[Ragnar]

Henry, you have a pocket motor checker, there is a cable and sensor available for it that will allow you to test RPM using the power supply from the track, very simple to do.

 

[Hank80]

Tom,
The DS pocket checker it simple. But does not provide the information I am looking for. Its great for a ball park type of number (rpms). The information I am looking for is: voltage, amp draw, rpm, torque.

 

[Ragnar]

For torque you will need one of the old style friction dynos, for voltage and amps use a multimeter to test while running the motor with the pocket checker to get values at different rpms. The nice thing about the pocket checker is that you use can use it with a variable power source to check RPMs at different voltages. You can get more elaborate dynos, but they cost a lot more (several hundred dollars), and they don't do that much more to justify their cost. RC dynos don't give accurate readings with slotcar motors, there is just too much difference in the motors. :wave: