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Motor Ident?

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Roger Dyke04/07/2020 21:00:57
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310 forum posts
14 photos

Hi All,

A while ago I purchased a DYS D3542/6 - 1000kv motor but never used it.

However, I've just installed it on my static rig to run it up and my findings were not as expected. It's spec. is supposed to be 555W, 38A, 1000kv, and 2 - 4S.

Results using a 3S battery:-

Prop 8x4

Volts 11.05

Amps 33.95

Watts 387

RPM 14000

------------------------

Prop 9x6

Volts 10.65

Amps 51.97

Watts 573.2

RPM 12100

-----------------------

I'm inclined to think that the motor is either the 1250kv or the 1450kv version and has been put in the wrong box. The box is clearly identified in two places but the motor has no identification at all apart from the manufacturers label.

What do you think or am I missing something?

PatMc04/07/2020 21:27:56
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4430 forum posts
538 photos

IMO it looks like it;s the 1250kv version. It would be easy to verify by measuring the rpm & supplied voltage with no load.

Use a couple of strips of self adhesive tape that are a contrasting colour to the motor body in order to measure the rpm.

Dividing the rpm by the voltage will give the kv.

Peter Beeney04/07/2020 21:39:28
1593 forum posts
59 photos

Just measure the motor revs without a prop on, Roger, that will give you a reliable datum to base all your other measurements on. I usually do it with a 12V car battery, that’s a good constant voltage supply, the load current is minimal; and for the same reason a fully charged 3S is fine, very little voltage sag.

Should be a ‘must do’ in every case case anyway.

Hope this helps.

PB

Sorry Pat, you beat me to it… must be late…

 

 

Edited By Peter Beeney on 04/07/2020 21:42:29

Edited By Peter Beeney on 04/07/2020 21:43:28

Roger Dyke04/07/2020 22:04:08
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310 forum posts
14 photos

Hi Pat and Peter,

Thank you both so much for your useful tips. I'll give it a go.

Roger

Roger Dyke05/07/2020 09:46:48
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310 forum posts
14 photos

Pat and Peter,

Just for info. I have carried out the test with no prop as you suggested and the result was as follows:-

Voltage: 11.98

RPM: 17300

So 17300/11.98 = 1440

So I take it that the motor is the 1450kv version. Not the 1000kv version as stated on the box.

Thanks for your help.

Roger

Dad_flyer05/07/2020 11:35:24
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311 forum posts
315 photos

If the no-load current is about 1A, that all matches up for a 1450kv and internal resistance of about 42mOhm.

Peter Beeney05/07/2020 12:14:17
1593 forum posts
59 photos

Hi Roger,

I probably wasn’t that far behind you, I’d already guessed that the unloaded revs were in the 17,000 region; 17,285 to be precise. But that in turn is making me more than a trifle suspicious too. Those current consumption figures do tend to stand out from the crowd a little, 52 amps to drive a 9 x 6 on 3S?? Put that lump in your model and you’d flatten the battery in less than three and half minutes! ….And just how far is 52A out of spec. anyway? Can we now barbecue some sausages on the ESC?

On the face of it, it appears you are getting an approximate 1,200rpm gain for a 22 ampere current flow increase. Based on this, to get to the sort of figures I might want to be looking at I think I might need to be looking for something like a 7 x 2 prop…

Do you by chance have a link to that motor please? I can find the 1,000 and 1,250 ok but not the 1,450. Perhaps it’s gone into hiding, if so is there a reason for this I ask myself?

Carry on dabbling, Roger, it’s all getting nicely interesting…

PB

Edited By Peter Beeney on 05/07/2020 12:15:24

Edited By Peter Beeney on 05/07/2020 12:17:35

Roger Dyke05/07/2020 12:18:20
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310 forum posts
14 photos

The no-load current was 4.5 Amps read back from the wattmeter when running full chat. 0 Amps read at idle.

Denis Watkins05/07/2020 12:20:02
4536 forum posts
123 photos
Posted by Peter Beeney on 05/07/2020 12:14:17:

Hi Roger,

I probably wasn’t that far behind you, I’d already guessed that the unloaded revs were in the 17,000 region; 17,285 to be precise. But that in turn is making me more than a trifle suspicious too. Those current consumption figures do tend to stand out from the crowd a little, 52 amps to drive a 9 x 6 on 3S?? Put that lump in your model and you’d flatten the battery in less than three and half minutes! ….And just how far is 52A out of spec. anyway? Can we now barbecue some sausages on the ESC?

On the face of it, it appears you are getting an approximate 1,200rpm gain for a 22 ampere current flow increase. Based on this, to get to the sort of figures I might want to be looking at I think I might need to be looking for something like a 7 x 2 prop…

Do you by chance have a link to that motor please? I can find the 1,000 and 1,250 ok but not the 1,450. Perhaps it’s gone into hiding, if so is there a reason for this I ask myself?

Carry on dabbling, Roger, it’s all getting nicely interesting…

PB

Edited By Peter Beeney on 05/07/2020 12:15:24

Edited By Peter Beeney on 05/07/2020 12:17:35

When it was in stock

htb1gh5zxi_vk1rksmryq6xwupxan.jpg

Dickw05/07/2020 12:25:34
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736 forum posts
99 photos

Is it this motor?

Dick

Denis is quicker!

Edited By Dickw on 05/07/2020 12:26:28

Roger Dyke05/07/2020 12:33:50
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310 forum posts
14 photos

Hi Peter,

Your thoughts are interesting. The more I look into it, the more it seems that the market for this motor is probably for quads and drones (with small fast props etc.). Of course, I maybe wrong (again).

I didn't purchase it from there, but below is the link to the DYS website showing the motor D3542/4 - 1450kv.

**LINK**

Roger

Roger Dyke05/07/2020 12:40:20
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310 forum posts
14 photos

Hi Dick,

Yes, the 1000kv one was the one it was supposed to be and what it says on the box.

I think it is exactly the same as the Turnigy D3542 series (but re-badged). Flash Hobby also badge them.

Edited By Roger Dyke on 05/07/2020 12:42:07

Dickw05/07/2020 12:51:55
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736 forum posts
99 photos

I don't know about quads and drones, but that 1450 motor would suit a faster model - perhaps something like a simple pylon racer type.

MotoCalc agrees that it would be around 52 amps on a 9x6 and 3s static, dropping to the mid 40amps in the air. If you fly full throttle all the time run perhaps time would be a bit short, but if you throttle back a bit once in the air and only use full throttle for a few aerobatics you should get 5min plus flights.

Only thing is, your 'on load' rpm figures look a bit lower than I would have expected.

Dick

Roger Dyke05/07/2020 13:02:13
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310 forum posts
14 photos

Hi Dick,

Thanks for your info. It will probably go back in the box now as my older years don't really lend themselves to the punch holes in the sky set. Nowadays I'm more of a tootler. Good to find out what it was though. Even if it wasn't my intended purchase.

Roger

Dickw05/07/2020 14:28:22
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736 forum posts
99 photos

Hi Roger

Nothing wrong with tootling, I do a fair bit of that myself these days smiley.

Mind you, I do like to have power available for take off, loops etc., and getting myself out of trouble. As an example, a data log of one plane last week shows a current draw of 43 amps at take off, but most of the flight was at part throttle using less than 20 amps - tootling even!

Dick

Martin Harris05/07/2020 15:40:08
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9409 forum posts
255 photos

I've seen your tootling Dick - anything up to 7 kW bursts of less than 2 seconds with 100 mph vertical climbs. Measured figures, not wildly optimistic estimates...

Tootling?

Roger Dyke05/07/2020 17:11:15
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310 forum posts
14 photos

Hi Denis,

Sorry, I accidentally missed you out.

It was in stock around 6th May a couple of months back.

Roger

Edited By Roger Dyke on 05/07/2020 17:11:45

Dickw05/07/2020 17:35:36
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736 forum posts
99 photos
Posted by Martin Harris on 05/07/2020 15:40:08:

I've seen your tootling Dick - anything up to 7 kW bursts of less than 2 seconds with 100 mph vertical climbs. Measured figures, not wildly optimistic estimates...

Tootling?

OK, so I like a bit of variety devil - but even that could be described as tootling when I slow it down and go thermal hunting.

Dick

Mike T05/07/2020 18:33:04
524 forum posts
45 photos

Mis-labelling problems apart, I have to say I do like those DYS motors, particularly the gold anodized ones, where typically, size-for-size, the shafts are thicker than other makes' equivalents. In addition to being stronger, its easier to get a good fit/grip with a collet.

Roger Dyke05/07/2020 19:28:46
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310 forum posts
14 photos

Hi Mike,

I quite like the look of them too and on the sizes that I use, do like the 5.00mm shaft which is 4.00mm on a number of others.

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