[EcoDrift.ru] Gotway MCM5, MSX, Tesla Comparison (Motors & Controllers)

[houseofjob]

Great writeup / teardown by @EcoDrift, per their usual. 

Interesting to see the secret of the MCM5 being wider magnets, wider than those of the MSX & Nikola's motor. 

 

https://ecodrift.ru/2019/02/04/gotway-mcm5-part-two/

Gotway MCM5 (motor/controller), MSX (motor), Tesla (controller)

Today we will study the main components of the Gotway MCM5 monowheel, and at the same time we will look at the MSuperX engine and Tesla controller. First MCM5 engine. This is an engine for a 14 ″ tire (bicycle size), although the native rim diameter is 10 ″ (automobile size). This is important in the selection of motorcycle tires, the dimensions of which are considered to be automotive standards, not cycling.

The engine turned out weighty:

7kg with nuts and washers:

Washers, by the way, are not needed, but the engine is separately supplied with them. Instead of washers, a large platform is now used, which protects the engine from turning.

View of the engine from the end:

It is really very wide. 
Wires are short:

Marking (manufacturer: HB, production date: April 2018):

Remove the engine cover:

Open:

The winding is tight, but not too neat:

All engines are wound in manual. But the winding is quite dense, nothing dangles.

Bearings in caps with a size of 6203 (this is important, since 6202 is usually put on 14 ″):

Interesting surprise:

The width of the magnetic 3.5cm. This is the widest engine that we met in monowheels. This means that the power available here is much more than in any other 14 ″ models. 

For comparison, the core Gotway MSuperX (MSX):

The magnets on the rim are also 3.5cm:

Magnets, unfortunately, not the best quality. Covered not with pure nickel, but with a cheaper nickel-copper alloy (yellow tint). Some magnets have traces of dirt, scuffs and even chipped. Do not forget that such a rim must be varnished before active use in wet weather to avoid corrosion of the magnets. 
Compare the wheel rim of the year 2016 with the MCM5, launched in 2018:

Top rim from Inmotion V8. Magnets are covered with nickel, no chips were detected. But even visually it is clear how much such an engine is weaker than a modern monowheel.

And now MSX (MSuperX) and its rim:

3cm magnets:

The engine is very similar to the Nikola engine, which we disassembled at the end of last year. This is understandable. After all, 18 ″ differs only in an increased rim. The magnetic circuit is exactly the same as the number of magnets: 56. 
The winding is dense, nothing dangles:

On the other hand, there are visible hand-wound flaws:

The width of the core is the same as that of the magnets, as it should be:

And now the controllers. The MCM5 controller was the first among the Gotway monowheels to be produced with field-effect transistors in large packages (TO247):

Such a housing improves heat transfer and increases controller reliability. And the MCM5 and MSX really had no problems with the power unit.

The reverse side of the radiator, on which the field-effect transistors are cooled:

4 capacitors:

Marking close-up:

The controller with a maximum voltage of 84V, so there are capacitors with a small margin of 100V. 
Bluetooth module for communication with the application:

View from the end (you can see how the power transistors are located):

MSX controllers are still equipped with the same field-effect transistors. And it is not yet clear whether Gotway will not switch to others, those that stand in Nikola. In the meantime, look at the controller from Gotway Tesla:

Back side:

Immediately installed fan:

Two capacitors:

Marking large:

The board has 12 field effect transistors in a small package (TO220):

Bluetooth card hid under the fan:

In the next part, we will look at the MCM5 hull elements.

[Marty Backe]

Thanks for posting this.

The MCM5 is a special wheel. And I know very few people take it up the kind of hills that I have, but I can tell everyone that the MCM5 is the most amazing steep hill climbing wheel ever made.

[csmyers]

This is fascinating. I want to know more!

[ElectriQ User]

I looked to control board for Tesla, it has just one fan, it is safe? I saw that the previous version had two fans on the backside.

[kelec_947]

They released in 2018 a version very slightly improved with a new motherboard and adds a fan and increases the surface of the heat sink. In addition, with the new motherboard there are new modes for LEDs. 

https://fr.aliexpress.com/store/product/New-GotWay-Tesla-electric-unicycle-CPU-control-board-replacement-mainboard-84V-67-2V-EUC-mainboard-upgrade/3896031_32879870523.html

 

[esaj]

On 3/4/2019 at 11:39 AM, ElectriQ User said:

I looked to control board for Tesla, it has just one fan, it is safe? I saw that the previous version had two fans on the backside.

I'd claim that the package-size / amount of power transistors and size / surface area (/ weight / heat capacity) of the heatsink are more important. Ideally, no fans would be needed at all (and many wheels don't have any), as they add a new failure point (mechanical moving parts) vs. plain passive cooling.

[KingOsmos]

This is cool, 

 

Why does the MCM5 board have 4 capacitors and the Tesla has just 2? Any ideas?

[esaj]

27 minutes ago, KingOsmos said:

Why does the MCM5 board have 4 capacitors and the Tesla has just 2? Any ideas?

My guess would be space issues, board size and how much room is there in the mainboard compartment. The MCM5 board has four 470uF caps in parallel = 1880uF (well, those caps have a tolerance of something like +-20%, but thereabouts ), while the Tesla board has two 1000uF caps = 2000uF. More caps in parallel does drop the ESR (resistance) of the caps , so theoretically more smaller caps in parallel could provide higher amperage, but since no-one's complaining that the wheels don't have enough power, it likely isn't that much of an issue either way    

AFAIK, the caps are there to provide the high current spikes when the motor coils are being turned on, the momentary (nano/microseconds) amperage can hit very high numbers (100's of A, if not 1000), which couldn't be provided "all the way" from the batteries, because of resistances added by all the wiring and connectors in-between. Also they'll likely take the worst voltage spikes off coming back from the motor(?). Usual symptom of a failed / bad caps in the mainboard is loss of torque (if not outright failure of the board, if they fail in short circuit for example).

Edited March 14, 2019 by esaj

[rinzler]

If the MCM5 and tesla are so similar (including possibly the same ports on the board) is it not theoretically possible to take the cut off switch on the MCM5 and mount it to the Tesla (obvs have to cut the handle to fit)?

I am entertaining this possibility. It would really help my Tesla become more tamed.

Since spares seem to be available via aliexpress then it could be a goer.

[houseofjob]

12 minutes ago, rinzler said:

If the MCM5 and tesla are so similar (including possibly the same ports on the board) is it not theoretically possible to take the cut off switch on the MCM5 and mount it to the Tesla (obvs have to cut the handle to fit)?

I am entertaining this possibility. It would really help my Tesla become more tamed.

Since spares seem to be available via aliexpress then it could be a goer.

The MCM5 handle dimensions / button plate are wider than the thinner Tesla handle I believe.

You might as well do the DIY with the button they're fitting on the 2019 Tesla v2

 

Edited April 26, 2019 by houseofjob

[eddiemoy]

I count on the stator 51 windings.  but they count 56 magnets.  it is interesting that they are not the same.  wish they measured the magnet size, not just the width.

[UniVehje]

It would be interesting to see these deep comparisons also between brands. Especially KS 18XL vs MSX motors. 

[Sprinkles]

I'm looking for some badass bearings for my msx. German or Swiss made? I've got almost 3000miles on the first factory set but now I'm Back to the old ninebot...... There's no comparison. Please, gimme a lead or I'm doing the OEM Monday

[RagingGrandpa]

For posterity:

Gotway MSuper (MSX / MSP 2000w / C30 motor) wheel axle bearing is 6203 RS.

ID 17mm
OD 40mm
W 12mm

Edited January 9, 2023 by RagingGrandpa

[Globewheel]

c30 motor from nikola and msx are they interchangeable? same thing? the rim is different but motor same?

[meepmeepmayer]

5 hours ago, Globewheel said:

c30 motor from nikola and msx are they interchangeable? same thing? the rim is different but motor same?

I'm pretty sure it's the exact same motor (minus the different rims).