Zhejiang Unite Electric Motor Co Ltd humour - MY1018

[Mathurin]

Values for customers!




Create the reputation, pursuit the excellence.
Get punch in the face here.


Does anyone have real world specs for the MY1018?
Something like actual no-load rpm would be nice.

[xyster]

Values for customers!


Create the reputation, pursuit the excellence.


Get punched in the face here.

Are we baked again, Mathurin?

[Mathurin]

Well, seeing how you're speaking in 1st. person plural and the op flew way above your head, I'd guess you are.

[xyster]

Well, seeing how you're speaking in 1st. person plural and the op flew way above your head, I'd guess you are.

Entirely possible there's some still in my system from High School.

[safe]

I see the problem.

Their charts don't match their stated numbers at all.

[safe]

Here's a bike simulation for that motor:

MY1018 Motor (sorry I got that wrong the first time)
24 Volts
40 Amp Controller
8 Speed Internally Geared Hub (Sturmer Archer)
Pedal Power Input can be observed.
Gears can be shifted and the charts reflect the changes.
Slope of a hill can be simulated.
You can select any rpm of the motor to observe.

With this setup your "motor only" top speed would be in 6th gear and you would go 24 mph.

[TylerDurden]

Does anyone have real world specs for the MY1018?
Something like actual no-load rpm would be nice.

Help me figure out how to measure that and I'll be happy to report back...

[Lowell]

Does anyone have real world specs for the MY1018?
Something like actual no-load rpm would be nice.

Help me figure out how to measure that and I'll be happy to report back...

I have an optical tach for RC helicopters that works nicely, I think it cost around $35.

[Mathurin]

Well, count the motor/drive gear ratio and have a speedo on the back wheel, also something to measure wattage on the motor. From that it should be possible to get rpm/Pin figures that could be used to scale the graph, or maybe plug right in. Obviously, the values would have to be within what's showed on the graph.

[Mathurin]

Ok, I used D-Man's data regarding Big Hank tires and Reid's Currie test with the DB. Assuming Reid's test was done at around 24v using an 11t cog, with 24t on the wheel, then I get 250w Pin @ 460RPM, so that's 3.3KRPM at the motor. With a 9t cog it's 562 - 4K



I dunno, moar data would be nice.

[Reid Welch]

Sorry I missed reading this thread until this moment.

I have an old Stewart Warner mechanical tachometer--the contact-the-shaft variety.

It needs a new rubber friction tip.

What if I run the Unite off a twelve volt battery and try for an rpm reading at the Unite's output shaft?
Would that be a help?

The motor is off of the bike at present, so if the tachometer works
this'll be an easy thing to do.

edit: ach! the Stewart is in perfect condition in its Canco tin can containment.
Since I last used it years ago the pot metal gear housing has apparently grown, and seized the internals.

---
I can perhaps do a physical count of the rpm at 6 or 12V, and you can extrapolate from there.

...Something like actual no-load rpm would be nice.

[safe]

You should try out the spreadsheet.

For example, since in the "real world" the controller makes a huge difference in the power output you really need to factor that in to get something worthwhile. When you use a 40 amp controller on that little motor it (should) pump out 590 watts at peak. Switch to a 20 amp controller and you only get 359 watts at peak. This is all with a supposedly 250 watt motor... so the "standard rating" is good to use for something like continuous running without heating, but for short bursts you can go way above that value.

In the case above the HEAT will be:

For the 40 amp controller at peak - 321 Watts of Heat

For the 20 amp controller at peak - 80 Watts of Heat

So using the 40 amp controller creates FOUR TIMES the heat at peak power!

[TylerDurden]

I propose to count the links in the chain and mark one link. (Same as a big slow gear.) And calculate rpms thereby.

I will try Dr. Gruber's 3.99 ammeter method for current metering (24V).


(Hopefully today...)

[Mathurin]

Hey Tyler,

How about... A speedo mounted on the rear wheel, output in km/h & wheel circumference set to 166.66cm? That way, when the computer displays a speed of say 30.6 km/h, it's measuring 306 RPM. Otherwise the RPM could be figured out of indicated wheel size.

Then check the no-load full-throttle RPM with the batteries at close to 24v as possible. It's probably safe to assume it's burning ~40w no-load. I'd also need to know the number of tooth on the motor & wheel cogs.

If the Unite graph is accurate, the motor should be spinning around 570rpm

[TylerDurden]

Ja,

I rekon I gotta buy a speedo sooner or later...

Used to have a cateye solar around here, but I think I tossed it.

Lemmee check-out the new DB, might just be the time for that.

[c_4]

You should try out the spreadsheet.

I would, but I can't open it.. Excel says it's not in a recognizable format..

[safe]

You should try out the spreadsheet.

I would, but I can't open it.. Excel says it's not in a recognizable format..

It was created in an old version of Microsoft Works on Windows 98. You would think that everything "old" would be supported by the newer versions, but I guess not so well.

There have been people here that have converted it and maybe they will jump right in and convert it for you again.

[Lessss]

Microsoft Works is barely supported by Microsoft Works.

You need better software. Download openoffice.org(free) or the equivalent.

[Mathurin]

So has someone determined something close to the actual freewheel speed for this motor? I'm back to thinking of using it for BB drive and am finding the ~20% difference in the maker's own specs to be quite significant, I mean putting out >300w at "no load" RPM seems a bit much.

[TylerDurden]

nah... we all got distracted by life.

I got nothin better to do now, tho. (still no speedo. Bought it, forgot about it)

[TylerDurden]

HA. Dead DMM battery... who woulda thunk a GETTOP HEAVY DUTY would die so fast.

[TylerDurden]

Mebbe that is GHETTO P.

Here ya go:

(70 links in the e-drive chain) * (72 chain revolutions/min @ full throttle)
70*72=5040 links/min

9t cog
5040/9=560 cog rpm

motor reduction 7.182 (as per unite)
560*7.182=4022rpm

4022rpm wheel-up

[Mathurin]

Cool, thanks!

This is what voltage, 24 or more like 28.8?

Also I don't understand the number of links thing, you really counted how many times a given link went around?

[TylerDurden]

That was a flat 24V.

I marked a link and counted how many times it crossed the cog (72).

A hair faster than 1rps.

[TylerDurden]

It didn't occur to me at the time, but I coulda stuck a wire in there and had it ring a bell on each pass...