MAC motor mod: did I miss something?

[alfantastic]

To put you in the picture, I bought a MAC 10T kit from Cellman around six months ago.
I took that one apart, to solve a small problem and also for my own interest to see the magic inside.
Before putting that one back together, I removed the grease from the internals and put my own very high quality lubricating grease on the gearing.
This quietened the noise of the motor a little.

Recently I purchased another kit from Paul, in fact exactly the same one.
I set it up on the same bike, same battery etc.. the only new part was the complete wheel.
On a test ride it was way noisier than the motor from six months ago, so I opened her up to put some of that high quality grease on the gearing.

Woah... Once opened, I noticed that the yoke housing has lots of neat holes drilled into it. Totally different from my original, which was a solid block.
So did I miss a planned mod that Paul is implementing on his MAC's? I usually scour this forum like a shitehawk :lol:

My grease mod hasn't quietened the motor down this time, but am happy that there should be bags of extra cooling within the motor assembly.

 

[ohzee]

Yea nice catch. Looks more like the bmc motors now.

Wonder if this helps with air flow and cooling ?

 

[Spicerack]

This is one of the improvements that's been in the pipeline for a while, good to see it's been implemented. I did it to mine ages ago along with a couple of other things.

 

[Spicerack]

Oh and it won't make much difference to cooling. I found the only way for these macs, if you insist on putting lots of extra power through them (I run 2-3kw) is sealing them up and oil cooling them.

 

[teklektik]

Not meaning to wander OT, but... I'm not sure what MAC puts in their motors but BMC recommends Mobilgrease 28. Since it's a bit of a specialty grease, it seems that they may have done a little testing to arrive at the choice.

 

[neptronix]

I put mobilgrease28 into my MAC and it has been happy with it for some time now.

Anyway, i'm thinking you have the new stator now. It might be a few percentage points more powerful and efficient. Lucky you. I ordered my MAC in early 2011 and am still kickin' it oldschool over here :lol:

 

[alfantastic]

This is one of the improvements that's been in the pipeline for a while, good to see it's been implemented. I did it to mine ages ago along with a couple of other things.

Just out of interest, did the noise increase somewhat?
It now sounds like one of those remote control cars you get for Christmas :lol:

 

[Spicerack]

Can't remember! It's not noisy though- certainly not like my rc cars!. Maybe next time you have it open, check all the bearings. I had one of the gear bearings go bad.

 

[shuckswon1]

Since the topic is Mac, and I am looking at purchaseing a new hub from cell man too. I was concerned to hear about the noise. Could the holes be contributing to the increase in noise you mentioned? Maybe changeing the pitch so that it's heard easier. Does the new motor you purchased also have the wire and temp senser up grades. Since you now have two macs what kind of torque and top end speed are you seeing with the 10 turn. Thanks for the post and pic.

 

[alfantastic]

Since the topic is Mac, and I am looking at purchaseing a new hub from cell man too. I was concerned to hear about the noise. Could the holes be contributing to the increase in noise you mentioned? Maybe changeing the pitch so that it's heard easier. Does the new motor you purchased also have the wire and temp senser up grades. Since you now have two macs what kind of torque and top end speed are you seeing with the 10 turn. Thanks for the post and pic.

I'm not sure whether it's the holes contributing to the extra noise or something else. It does seem to have a louder motor whine than my original MAC, which didn't have the the holes mod.
Not sure either if it's got the wire and temp upgrades. You'll have to e-mail Paul on that one.
I see approximately 27mph on the flat, and the torque is unbelievable at 48v with Cellman's 30A controller.

If all the new modded MAC's are this noisy, then I would advise that you try and hear one first before building any stealth machine.
As I mentioned, mine now sounds like an RC toy car, not offensive, but people can definitely hear me coming.

Maybe mine's a little noisier than others, but we need some feedback from other owners to come to a definitive conclusion :wink:

 

[DAND214]

Do you have any miles on it yet?
I have 2 8ts and one is quieter than the other. Differant bike frame can also make a differance.

I know when I blew the clutches in them and put BMC clutch with green gears it was almost silent. I cut back on the amp and phase to stop blowing clutches.
I don't think they like 62v with 65+amp with 130 phase. Now I'm down to about half of that and there still running great.

Dan

 

[dallasdick]

Maybe mine's a little noisier than others, but we need some feedback from other owners to come to a definitive conclusion :wink:[/quote]

I just finished an install of a Cellman MAC6T with Infineon EB312(3077 72VMAX) Controller on a KHS XCTeam bike. It's a rear hub gear drive unit massaged for higher output (read: speed). I took it out the other night and ran it in all three speed settings. When I got up to about 25mph on setting 2 it started whining a bit, but not any louder than my Magic Pie III or my WE motor. On the 3rd setting though, it started screaming at me when I hit 30mph, and when I hit 35mph it was pretty scary. My CA-DP logged 1909W at 35mph peak which quickly tapered down to around 1100W at speed.

I am pretty sure the whining is louder because the holes are there and don't contain the noise emitted from the inside chamber. That internal chamber is like an echo box when the bearings are spun up, holes allow the sound to escape. The new gears are a higher quality nylon, similar to BMCs material, they could also contribute to the noise.

 

[veloman]

Both my Macs (2010 and 2011) are quieter than my 9c. You can't hear them past 30ft or so.

 

[alfantastic]

I am pretty sure the whining is louder because the holes are there and don't contain the noise emitted from the inside chamber. That internal chamber is like an echo box when the bearings are spun up, holes allow the sound to escape. The new gears are a higher quality nylon, similar to BMCs material, they could also contribute to the noise.

I think you could be right there. The new modded motor is just a replacement for my original one. Absolutely everything else is the same, controller, battery, bike, the lot.
Which leaves the only noise contributing factor to be the holes in the yoke assembly.
Wonder if the yoke spins up a little faster too, with the reduced weight.
As for cooling, I max at 1500 watts, so I doubt heat would be a big issue with modded or non modded motor.
Maybe this is what all you power monsters out there have been waiting for :wink:
Would be interesting to do a side by side comparison of temperatures on both motors though.... Anyone...

 

[neptronix]

Over 1500W or so, the MAC can get really noisy.

Eh, same with the DD motors. I remember when i was running 2000W constant on the magic pie, people could hear me coming. I could see the look of surprise on their faces, lol

 

[GrayKard]

I recently bought a front and rear 10t Mac from cell_man but haven't run them yet. Now I'm curious so I'll spin them up tonight to see what kinda music they make. 8)

Gary

 

[alfantastic]

I recently bought a front and rear 10t Mac from cell_man but haven't run them yet. Now I'm curious so I'll spin them up tonight to see what kinda music they make. 8)

Gary

I found that when there wasn't any load on the wheel, modded and unmodded hubs both sounded similar.
It's under load that there is a difference in noise output.

 

[alfantastic]

I recently bought a front and rear 10t Mac from cell_man but haven't run them yet. Now I'm curious so I'll spin them up tonight to see what kinda music they make. 8)

Gary

Any idea if you've got the new modded motors?

 

[GrayKard]

No idea but since I just got them a couple of weeks ago I figure they are the newest version. I'm not opening them up to find out though. Still haven't spun them up, too busy building an Ebike for a friend.

Gary

 

[Architectonic]

Today I got one of the new MAC clutches too, they look suspiciously similar to the BMC v4 clutch. :wink:

 

[cell_man]

Hey guys,

Apologies for bringing this old thread back from the dead, but a customer linked to it and I thought I'd give my tuppence worth.

I've also heard this back from a couple of customers that the newer stator is more noisy, but I think it was more from customers researching rather than personal experience. I can't say for sure, but something I have noticed is that any Mac with the composite gears will get quieter once it has had some usage and the sharp edges are knocked off those gears as it were. It can take quite some time for the gears to bed in, it doesn't happen in a couple of days either, more like weeks or months. I wonder if what was noticed here was more down to the fresh set of gears more than anything else. Not saying the holes in the yoke doesn't effect things, I'd have to try some tests myself to see if I could notice some difference.

The new yoke makes it easier to get consistent results when they are stamped, having holes apparently makes the process easier and that is the primary reason for going this route. If it indirectly saves some weight, possibly helps cooling, or makes it more like a very similar motor that is about twice the price, well that is a bonus Another nice feature of the holes is that you can confirm the clearance to the windings, it is pretty tight inside and it was something that I used to have concerns about.

Thanks
Paul AKA Cell_Man

 

[gensem]

Hey guys,

Apologies for bringing this old thread back from the dead, but a customer linked to it and I thought I'd give my tuppence worth.

I've also heard this back from a couple of customers that the newer stator is more noisy, but I think it was more from customers researching rather than personal experience. I can't say for sure, but something I have noticed is that any Mac with the composite gears will get quieter once it has had some usage and the sharp edges are knocked off those gears as it were. It can take quite some time for the gears to bed in, it doesn't happen in a couple of days either, more like weeks or months. I wonder if what was noticed here was more down to the fresh set of gears more than anything else. Not saying the holes in the yoke doesn't effect things, I'd have to try some tests myself to see if I could notice some difference.

The new yoke makes it easier to get consistent results when they are stamped, having holes apparently makes the process easier and that is the primary reason for going this route. If it indirectly saves some weight, possibly helps cooling, or makes it more like a very similar motor that is about twice the price, well that is a bonus Another nice feature of the holes is that you can confirm the clearance to the windings, it is pretty tight inside and it was something that I used to have concerns about.

Thanks
Paul AKA Cell_Man

Paul,

If im not mistaken I heard there was a new clutch coming, is it?
Asking because I need a light weight commuter and mac would be the motor of choice.

Im thinking of the Samsung NMCs 14s 7p
12fet controller @40amps
8t mac on a 26" wheel.

 

[neptronix]

Get a 10T and run higher voltage..

 

[gensem]

Get a 10T and run higher voltage..

Im afraid to strip the gears using a higher T motor Nep...

How much power are you using now? Is your area hilly?

 

[neptronix]

Get a 10T and run higher voltage..

Im afraid to strip the gears using a higher T motor Nep...

How much power are you using now? Is your area hilly?

The gears are pretty strong these days. It's the clutch that is the weak point now, but if you buy a newer motor with the BMC V4 style clutch, it could hold up long term. Just keep the phase amp to battery amp ratio low, which limits torque at the lower RPM end of the power band ( which is very high on these motors anyway ) .. that's the secret to preserving the clutches, or at least it has been for this 250lb rider scaling fairly steep inclines at 1600-2600 watt peaks.

I typically run 38v/42A on my 8T, sometimes run 46v(12S)/42A.