Whats the smallest electric motor you can dyno

[Tzi]

Not having a dyno myself, nor ever used one... I need some help answering some questions.
How do they work?
What kind of results do you find out?
What size motors can you dyno?

[JohnRobHolmes]

The answer is... how small of a motor dyno can you build? The smaller the motor, the higher resolution needed in instrumentation.

The results depend on the equipment. The end goal for a dyno is to know the power, torque, and efficiency curves of the test motor. The presentation of data can be quite different between dyno types and data analysis goals.

Looking to dyno some wee little servo motors? You could build a servo dyno if you want to put in the effort.

[EddieO]

The Fantom would probably be the choice here, as they make a slot car kit for it (not sure if they are in production anymore). They also have special slot car software for smaller motors.

The Turbodyno has been adapted before, but it did not work well...Robi can be adapted too, but the software is kinda off......so its not perfect.

Later EddieO

[Tzi]

Hmm.. thanks for the input guys.
Yes, I'm looking at putting some servo motors on a dyno.
Last night I came up with a crazy idea of using rebuildable slot-car size motors in my winch but want to know if its worth the effort.

Do either of you have the facilities to do what I'm after ?

[JohnRobHolmes]

If the slot car motor is bigger than your servo motor I can guarantee the effort is worth it if you want more power. Then you will need bigger gears.


I don't have the slot car software for my Fantom Dyno. I could probably get it though.

[EddieO]

I rarely use my fantom.... You need the special slot car adapter to actually hold the motor...I think they were $100 or so...the ass that makes the software I think charges like $80 for the slot update.

I can tell you a slot car motor is gonna be tough to work on a winch...they are all designed to be rpm machines...not a lot of torque....it may work though.

Later EddieO

[Tzi]

So far the servo manufacturers are pretty closed-shop on their product specs so I figure I'll have to find out myself.
When you ask about motor RPM and gear ratios inside the servo they tend not to reply.

I'm not sure that more power is what I'm after, just a good combination of more-speed and same-power... and its nice to put some numbers to it.
Already there are servo-based winches that are strong enough to do serious damage if you get your fingers in the way. Not sure I want to build an amputation-machine haha

[Tzi]

Originally Posted by JohnRobHolmes

You could build a servo dyno if you want to put in the effort.

I've been searching the net for how to make a dyno, and it appears pretty simple, and theres software freely available.
Just gotta figure out how it all works before I start building. I have a hard time working out how the software calculates everything by just knowing the mass of the load, and reading the rpm.

I figure I need to know the following...

• Max RPM
• Torque
• Normal Amp Draw
• Peak Amp Draw

[Olle P]

You can do it even simpler than that.

At no load and typical voltage feed measure:
Speed
Voltage
Current

At stall (and with reduced power feed to avoid overheating) measure:
Torque (Have a known arm push or pull on something that measure static force.)
Voltage
Current

Then from that it's very easy to extrapolate and interpolate the data you want.