Fine Designs XLT-1

Yea I am also having trouble with Fine design.
Ordered a few cheap pinion gears from them to see how they were.
They were shipped about 1.5 weeks ago so should be here soon.

I have sent 3 e amails to them over the last week asking about the Lehner 1930/6 motors and if they had any in stock.
Still haven't heard any replys back from them. Makes you a bit weary of ordering anything from them if they can't reply to an e amil in a week.

[glassdoctor]

I've never done this and it's not my idea... but I think you can use a slave motor to spin the rotor (XLT) and measure the voltage across a coil, to somehow figure the kv.

Also, I read you can measure the rpm while it's running using a scope. (or use an actual tachometer) With the voltage into the motor and the rpm measurement, you can calc the kv.

If you can figure the kv.. that would tell you what it is.

Originally Posted by glassdoctor

I've never done this and it's not my idea... but I think you can use a slave motor to spin the rotor (XLT) and measure the voltage across a coil, to somehow figure the kv.

Also, I read you can measure the rpm while it's running using a scope. (or use an actual tachometer) With the voltage into the motor and the rpm measurement, you can calc the kv.

If you can figure the kv.. that would tell you what it is.

The first method you listed will work using any of the 10th scale/540 motor dyno's. The problem is finding one with or producing a coupler with 5mm shaft capability on one side. I never did either but came up with a better solution. Sold the XLT4(with disclaimer) on e-bay and forked out the coin for Neu 1515/1y; Problem solved!

[What's_nitro?]

Couldn't you do the opposite and spin the motor while measuring the output voltage? Attach a voltmeter between two leads on the motor with a diode in series and adjust the speed of the motor until the voltmeter reads 1 volt. That should give you the unloaded kV, right?

[suicideneil]

If it was a normal brushed DC motor I would have said yes, but BL motors having three phases and all makes me wonder... that said, its beyond my knowledge base so buggered if I know anyway- sounds like an idea though.

I like the 'sell it by buy something better' plan personally

[What's_nitro?]

You just need to choose any two motor leads and measure the pulses between them. The diode only lets through the positive pulses instead of letting the AC go to the meter. A capacitor would help to smooth the pulses and get better readings. I suppose you could just read the AC voltage produced until you get a 2V peak-to-peak reading.

[BrianG]

Or, you could create a simple three-phase bridge rectifier, add a filter cap, and measure the DC voltage...

[lincpimp]

Will do Brian, as soon as MIT accepts my applicatiion and I graduate in thermonuclear abstract quantum applied theoretical geometric engineering, with a focus in electrical diagram analysis!

Is it Brian or Brain?!

[BrianG]

lol, that was a far cry from anything in the MIT class! 6 diodes and a cap isn't all that complex. Just follow the wires...

Actually, you use something like that circuit every day; the alternator in your car!

And it's Brian...

[lincpimp]

Luv ya Brian, could not help myself. Saw someone else make the Name mistake and get scolded by ya!

You are much more knowledgeabe than I on the circuit stuff. I can use a voltmeter and have a basic understanding of DC. And that is only from 15years in an auto body shop, where a shorted wire causes the body man's head to explode! I always got stuck under the dash fixing the wiring, airbags, stereo, etc.

[BrianG]

I'm not an expert like Griffin and a couple others, but know enough to get by for what I need. Understanding the basics, designing some simple circuits, troubleshooting and repairing things like amps is about all I do now. Used to be a bench tech, then worked part time at a stereo shop repairing amps and installing stereos/alarms/remote starts/etc. More of a hobby now, but it sure helps to know HOW things work. :)

[lincpimp]

How things work? Its all smoke inside stuff! When you charge stuff up it just pushes the smoke back to the correct side. Even I know this!!!!

[BrianG]

OK, you are NEVER to touch anything of mine that is electronic!

[What's_nitro?]

...and if you let the smoke out, things don't work anymore!

[lincpimp]

HAHA

I have you old emoil batteries remember!

Have not managed to get any smoke out of them yet, but I am still trying. I was using them when Griffin's modded MM let out some smoke, but they are fine.