GM BLT-800W bench racing

[neptronix]

[youtube]PI1nooxDGus[/youtube]

Arrite, here's the goods.

38v: 1016RPM / 0.91A x 38v = 34.2W loss
57v: 1510RPM / 1.1A x 57v = 62.7W loss
78v: 2030RPM / 1.3A x 78v = 101.4W loss

Seems like rather good no-load figures, when thinking of RPM per amp.

Here's how it compares to my MAC 2000W motor:

38v: 2688RPM / 3.15A x 38v = 119.7W loss
57v: 3878RPM / 3.6A X 57v = 205.2W loss
78v: 5037RPM / 4.0A x 78v = 312.0W loss

 

[neptronix]

WOW! looking at some specs of hub motors; it seems that a lot of hubs have much worse no-load speeds. 1.5-2.25 amps at 36v is the norm for the 9C style motors, and that's while spinning at 1/3rd the RPM.

OK, now i am back to being more excited about getting the 800W motor in my hands :lol:

I hope no-load amps mean what everyone is telling me that they mean - that they are some kind of indicator of power delivery and efficiency that can be had from a motor..

 

[Arlo1]

No load amps meen you can spin it faster I am not the one who knows the max mechanical limit due to magnet bonding thats for you to judge....

 

[Miles]

I hope no-load amps mean what everyone is telling me that they mean - that they are some kind of indicator of power delivery and efficiency that can be had from a motor..

Well, they are a factor. You need to also determine Km to get the full picture.

http://www.endless-sphere.com/forums/viewtopic.php?f=30&t=45489

 

[jmygann]

what is the second motor shown ??

 

[spinningmagnets]

I also asked about the motor on the right. It is the MAC electric lawnmower motor, and that thread showed that when searched, there were electric snowblowers and floor polishers that also used that motor. Good form factor as far as shape/size for non-hub. Laminations are too thick for high RPMs, and the motors highest efficiency is around 1600-RPMs.

There is a almost identical motor from Ariens, shaft is 17mm, and kV is 60-ish. The MAC has a fat 7/8-inch shaft diameter (22.5mm?), and kV is 70-ish. Both have a cheap freewheel shaft adapter or chain sprocket available, but have yet to find a common pulley that will fit 7/8-inch or 17mm. Both "might" work with 20-inch driven wheel on a single stage @ 36V / 48V...

"2000W MAC lawnmower motor"
http://endless-sphere.com/forums/viewtopic.php?f=30&t=40166

"Ariens 1.7-HP lawnmower motor"
http://endless-sphere.com/forums/viewtopic.php?f=30&t=41190

 

[neptronix]

I've got awfully bad news about this motor.
The 650w and 800W motors are definitely more suited for trike use. They are just too damn wide for even my cargo bike frame.

I can't find a damn place to mount it proper. The motor is so wide that it has to be mounted with a significant offset in order to line up with a disc brake mounted sprocket... this is not a problem on a trike, where you have a bunch of space underneath the seat plus an axle to hook up to.

On the BLT 650, you can mount the motor with an offset because most of the weight rests on the side where the sprocket exits ( as the back half of the motor is basically hollow ). This works if you don't have a chainline interference issue. I have a 60T chainring for pedaling at high speeds on a 24" wheel, so this won't work for me. If you have a 700c setup ( doesn't need such a big chainring ), you might be able to mount the motor on a Yuba Mundo.

If you're OK with the motor offset on the 650W motor, then i could see using a jackshaft to help out with the pedal chain interference issues, but the 500W motor would be better for this use.

I think i will convert this motor into a bench grinder or something as i don't have a suitable frame for using it. I'd love to see someone else play with the the 800W on the right frame though.

 

[iovaykind]

How about a chain guide/roller to get it out of the way?

 

[neptronix]

I can see using chain guides or a jackshaft as a solution, but the biggest problem would be having 10lbs of the motor hanging out on one side, making the balance of the bike weird. I also couldn't cover up that side of the motor with panniers, they'd stick out funny. I don't like that.

 

[Qwiksand]

I picked up one of these BLT-800s when I bought the 500 I'm using on the stinky. I plan to use it in a ( as yet unbuilt) delta trike. It is a huge motor and weighs 20.12 lbs- may work in a custom fat bike frame, but I think it'd balance easiest in a three wheeler. I'm hoping the 800 will take 20s ok- let me know what you think safe continuous/peak watts will be.

 

[neptronix]

I picked up one of these BLT-800s when I bought the 500 I'm using on the stinky. I plan to use it in a ( as yet unbuilt) delta trike. It is a huge motor and weighs 20.12 lbs- may work in a custom fat bike frame, but I think it'd balance easiest in a three wheeler. I'm hoping the 800 will take 20s ok- let me know what you think safe continuous/peak watts will be.

Cool, glad someone else will take up the cause of experimenting with one.

Spin it up and give it the right gear ratio ( i'd say gear it for ~35mph if you're gonna run 20S ) and it should be a tire shredder. On the golden motor forums, someone remarked that it was stronger than the magic pie, which is saying a lot:

[youtube]rN8YfwFB61o[/youtube]

( skip to about 3:00 on this video to see me dumping 8000w into the magic pie. Note that i have to feather the throttle from a stall to prevent wheelies :lol: )

 

[jmygann]

i have an old 20 in hub motor and 48 volt Li... What speed could I expect on 48-50 volt with MP

 

[Ruudi]

Golden motor is usually not too bad about their specs.



( note, they make these up to 2200W rated )

Why are this motor stator laminations not in straight line ? Why are they bended or under an angle like that? I have seen it on some dc brushed fan motors.

 

[parajared]

For $100 I may take up the cause with the 650 watt model.
I have a gng on my bike right now. I think I can convert the pain in the rear belt portion of my GNG to a chain drive for around $100, but I may rather just buy one of these guys and swap her with my gng motor for a nice single reduction setup.

 

[neptronix]

For $100 I may take up the cause with the 650 watt model.
I have a gng on my bike right now. I think I can convert the pain in the rear belt portion of my GNG to a chain drive for around $100, but I may rather just buy one of these guys and swap her with my gng motor for a nice single reduction setup.

Don't bother with the 650W. the 800W is not much heavier and the case sizes are the same on both.

 

[parajared]

92v on the BLT-800 spins at 2500rpm unloaded

ah, I guess the single reduction idea is out, even on 44 volts you would be like hey guys, check out my awesome 190 tooth reduction setup.

It would seem that if you want to peddle at a cadence of 80 rpm (26" tire and standard crank arms) you need a motor in the ballpark of 10 KV.
(keeping the motor in it's efficient rpm range, keeping voltage at 44, keeping gear size to standard sizes, keeping this to a single reduction, assuming you want to assist in pedding)

 

[parajared]

A proper two stage reduction for GM BLT at 44 volts would be a couple of 13teeth 56teeth reductions according to my calculations.

I am assuming the GM BLT has a 13 tooth sprocket on it right?

 

[neptronix]

You'd get an awfully low power density out of it doing that.. :/

No load on the 650W @ 48v is around 900rpm, so yeah, you need about two 3:1 reductions.

But dude, why bother with those. What was my motor, 19lbs? You could get a 1000W continuous BMC/MAC motor at about 6 pounds and use the same double reduction business to get a motor 1/3rd the weight down to crank speed. Then you'd have a wonderful poor man's ecospeed!

This motor's good for single gear ratio to the back wheel really.. if you wanted a mid drive, the 500W unit would be better anyhow due to it's better size/weight ratio.

 

[parajared]

Yeah, this motor would pair nicely with a GEBE ring. A MAC 12T would be the ideal single reduction mid-drive, but a MAC from emissions-free is $250, a GM BLT is $100. Sigh...

 

[sendler2112]

so high RPM operation is not going to be very good. Maybe it can do 1500rpm at ~80% efficiency? still kinda sad.

The sprocket at the end is 14mm internally and fits a #41 chain.

This is good news to me. The low rpm that is. I am planning a mid drive conversion for my recumbent. The intermediate shaft rpm will be 343 at 40mph when on the 11t in the rear due to the 13:17 multiplication on the crank side that I need to get the crank back down to 85rpm on the 53t. I could probably wish for a little more power to get up the hills but most other in runners are wound for 3,000 rpm and cost 3 times as much. It's a really long motor though. A recumbent (or a trike) is about the only application with enough room for a motor that is that long.

 

[sendler2112]

Video of BLT-650 spin up at various voltages.
38V/ 1016 rpm/ .91A/ .034W per rpm
57V/ 1510 rpm/ 1.09A/ .041W per rpm
76V/ 2030 rpm/ 1.30A/ .0487W per rpm
26.6 rpm per V
.
.
http://www.youtube.com/watch?v=PI1nooxDGus
.
.

 

[joec]

Hi guys, I just came across this thread. I'm a long-time lurker and intermittent question asker, my main interest is in building wheelchairs for an indoor sport called power soccer.

Sendler22112, thank you very much for posting that video. It appears that this motor has a lower no-load current than the motors I use, and they have a voltage constant that's FAR lower than any other motor that's been feasible for me to consider, which would let me use a simple chain drive instead of a two-stage reduction.

Can you (or anyone) say anything about this motor's winding impedance? I'm trying to run a motor simulation to see if this thing is going to get me more performance than what I'm using now (the NPC T74 - two per chair) before buying them and figuring out how to use a brushless controller. Also, do you see any other issues with using this thing in a wheelchair where acceleration and pushing power is a big deal?

Very exciting!

 

[BYqSXt8Z]

Zombie thread resurrection powers, ACTIVATE!

Sorry to do that, but I prefer getting an old thread going where people already know about the motor than to create a new one and spread all the information in an unfindable mess.

What are the 5 wires for on this motor? I can't find the documentation... I mean there's obviously the 3 phase motors, but the the hall effect sensor cable has 5 wires, so 3 for hall and then... Is there a temp sensor in there too?

Sent from my CLT-L04 using Tapatalk

 

[Golden Motor Canada]

I believe it is the three hall sensors and positive and negative on the 5v system.

Gary

 

[BYqSXt8Z]

I believe it is the three hall sensors and positive and negative on the 5v system.

Gary

Thanks!

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