What's the best way to determine the wind of a motor when its wind is unknown?
What's the best way to determine the wind of a motor when its wind is unknown?
Google it? I know, seems like an "evasive" way of answering your question...but, in all honesty, that's how I started learning a good portion of RC-related stuff.
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If you know the size of the motor and the kV, you can usually go to the manufacturer's website and get that info. If you do not know the kV, you can still determine the wind D or Y be looking at how the wiring is terminated inside the top of the can. I have forgotten which is which and what it looks like, but it's likely in a donhuff post here somewhere.
Vac-U-Tug Jr (13mph)
It?s a TP (TP 5690) Motor ordered special from China. The KV of 680 is offered under Y and D winds and the 3rd party seller isn?t sure which wind I got. I figured I could take it apart to see the winding configuration, but I was hoping for a nifty trick or tip that makes it even simpler like maybe the controller could auto sense the wind or something to that affect.
I see that on the website, either 4Y or 8D for 680kV. Weird. You might need to remove the rear end bell, take a clear picture of the windings and how they're terminated to the motor leads, and contact donhuff
Vac-U-Tug Jr (13mph)
Look through the holes in the rear end bell and see if you can find a short piece of black heat shrink that has been mashed down and embedded in the strands of wire. This indicates that it is a WYE wind. If no black heat shrink, then it's a Delta.
In some very rare cases, like on the AquaCraft 1800kv, that piece of heat shrink will be on the front (PTO) end of the motor.
I assume you want to know this because you don't want to run "high timing" on a D wind? I run all my ESCs on 15* and never think twice about which wind is in the motor. I have been doing this for the past 3-4 years without any problems.
Don. I have a mislabeled motor. How can I tell by looking at it the actual wind? How do I count the wire winds ?
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That's a lot harder to do and not usually possible without taking the motor apart and unwinding it.
If you can take one lead and separate it enough to count the strands. Then you can make a better "guess" at it. If you know about how many strands a slot in the stator will hold, then divide that number by the number in the lead. IF it's a wye, the number in the lead will be accurate, if a delta, then you'll have to divide the lead count by two because there are two ends of bundles in each lead. The pizzer is that nobody has a clue as to how many strands are in a slot, for each particular brand, except me and now Terry. Terry only knows about a couple of motors and I know only maybe a dozen.
What brand is it?
But the easier way is to measure the full throttle RPM ( I use an airplane photocell tach) and the voltage WHILE RUNNING AT FULL RPM. Divide the RPM by the voltage and you get the KV. Then compare the KV to manufacture specs.
BTY,
I curious as to how you know that it is mislabeled?
My buddy blew up the motor. The cooler said one wind and when we took it apart some numbers were etched on it that didn't make sense. We were running it on 10s. pretty sure it should have been 6s. it's a TP. I took it apart. what do you mean divide by the leads. aren't there 3 leads?
On a D wind, lets sat that you weave a single wire through it to do the wind, and you do all three legs which will be three separate pieces of wire, when finished, you'll end up with six wires sticking out of the stator.
To terminate the "wind", you have to take the start of #1 wire and join it to the start of #2 wire, and twist together and solder to make "#one leg lead". Take the start of #3 and join it with the finish end of #1, twist and solder for "#2 leg lead". Finish of #2 and finish of #3, twist and solder for "leg lead #3" .
For the Y wind, you will twist and solder together, the start end of all three legs, thats what's inside that little piece of black heat shrink in the back end of the motor windings. Now wind the stator and when finished you will have three wires sticking out of the stator. These are the three leg leads.
When you have a motor that your not sure of the kv. I check them with a 2s pack and find out the kv. That way I'm positive that I won't over rev it and sling a magnet off.
The TP 40 series usually has around 100 strands of 27 awg wire in them. So a 3 delta would have say 66 strands in a leg lead. Then half that because it has the ends of two separate bundles, so 33 strands. Then those 33 go through the slots 3 times for 99 strands per slot.
A 3 wye would have 33 strands in the leads and that's all, because the other end of all three legs are already soldered together.
That's why sometimes a delta will have big leads compared to a Y , especially a low turn delta.
Also remember that for a 3Y at say 1800kv, if we were to terminate it as a delta, it's kv will be 1.73 times the Ys kv. That would make it a 3114kv, and that's why you have almost twice the turns for a D compared to a Y, for close to the same kv.
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