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Dec 04, 2015, 11:16 AM
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Pacem_Lumine's Avatar
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"New" motors being sold? How to be sure they are.


Recently, I had cause to buy new motors for a DJI Inspire 1. At the present time, these seem to be back ordered or in short supply, unless you can wait a long time to receive them in the USA from China. An authorized dealer should stock them locally, but sometimes they are out of stock.

Wanting new parts soon rather than later, I looked in the usual place, that popular auction site and other internet locations and found many ads for supposedly new "DJI Inspire 1 Motor". These were the correct PART5 CCW or PART4 CW "WM610 3510" part for the aircraft.

Looking much closer, some didn't look so great. The sellers claimed they were new. On the popular auction site, the Condition was listed as new.

I'm here to say that this 'new' claim was not the truth. Obviously some of those motors are used, and most likely from crashed or salvaged aircraft. OK no big deal, but bad things do happen to high powered motors when the aircraft is crashed and the prop is suddenly stopped with the motor running at high power.

So stack that on top of a lie. Hate to call it out but I was not happy to see this level of dishonesty.

This applies to all 'copter motors and ESCs, not just the DJI Inspire motors. Those just happened to be what ticked me off, in my hour of need, considering the prices being asked for them and the deliberate falsehoods about them being new.

- If it has ever been in a crash, it is not new.
- If it has ever been run, it is not new.
- If it has ever been installed, it is not new.

But none of the ads said anything about it having been in a crash, used, or installed, they just claimed that it was "new never used".

So, how to tell if it is used? You must look closely.

Used motors and ESCs may have:

- Scratches on the wires and connectors and where the wire comes out of the motor casing.
- Wear or rubbing marks anywhere.
- Disturbed mylar tape or heat shrink tubing on the wires.
- Any sort of dust or dirt specks, especially in small crevices where wires join the board
- Any sort of dust or dirt specks, especially in the top vents of the rotor.
- Black foam or plastic panel on the ESC (new motors don't come with this separate item)
- Prop locks or screws on the motor (new motors don't come with this separate item)

Most importantly, please check any motor by looking very carefully at the copper windings inside the hub, from the top and through the bottom. This is crucial, as ANY darkening of the windings indicates the motor has been overheated and winding failure (short out) is likely.
It can take the ESC with it and if the prop slows too much, we know what happens next.

The above visible factors strongly indicate a motor is NOT new regardless of claims, but just a second hand one.

(During an Inspire 1 repair or when considering a "left (or right) arm component WM610" -the "boom" the motors mount to - Look at the area around the four motor screws to see if it has a melted look. If so, the motor previously mounted there has been overheated and the arm should be inspected to be sure it is still structurally safe.)


Following is a graphic of images that show what to look for. I hope this helps.
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Dec 04, 2015, 11:46 AM
Surface, Air & Water Rc Toys..
If they are not in their original sealed package/box and from reputable seller/dealer, I don't buy it.
Dec 04, 2015, 12:08 PM
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Originally Posted by freechip
If they are not in their original sealed package/box and from reputable seller/dealer, I don't buy it.
Or accept that it is probably used and should be treated that way.
Dec 16, 2015, 10:12 AM
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Pacem_Lumine's Avatar
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Sometimes things get opened for being checked to make sure it's the right thing, or for whatever reason it's out of the package but has not been installed. That's fine with me. Some things don't come in individual packages, for example the Inspire1 motors come in a bulk pack of ten. It's a big foam block with 'slots' for each motor to fit in. They wrap it in film and ship it. Close inspection of the pictures is helpful to me in those cases.


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