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2kw 2 speed brushless hub motor

Posted: May 30, 2008 1:34 am
by John in CR
I picked up an interest hub motor that I'm having trouble getting running. The interesting part (at least for me) is that it has dual windings with a mechanical switch, to creating a high torque low gear and high speed gear. Below are 2 pics of the phase wire connector end with the switch in it's two positions, and the 3rd pic is of the hall sensor end. I don't see or smell anything visibly wrong, but I'm not getting any signal out of the hall sensors.

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Re: Erato 2kw brushless hub motor help needed

Posted: May 30, 2008 9:54 am
by Drunkskunk
interesting motor with that few windings, it looks to be fairly high speed. Whats it out of?

have you tested the hall sensors individualy? do you know the phase they are setup for?

Re: Erato 2kw brushless hub motor help needed

Posted: May 30, 2008 10:14 am
by The7
There are 18 coil poles.

I am very interested in this motor.
Could you tell me more how did you test it?

With what controller?
Battery voltage?
How to select the mechanical switch?
How many magnet poles (or pole-pairs)?
Is it a gearless drive?

Re: Erato 2kw brushless hub motor help needed

Posted: May 30, 2008 2:52 pm
by fechter
That is cool.

I've never seen a switch setup like that.
Yes, tell us how it gets switched.

The hall sensors typically run off 5v. You can test the sensors with the motor apart by putting 5v (or a 9v battery) to power them, and put a small magnet up to each sensor in both directions and see if the output toggles.

You should measure something on the hall signal wires. If the halls are blown, they typically show around .3v or less on the signal output regardless of magnetic field.

Re: Erato 2kw brushless hub motor help needed

Posted: May 30, 2008 3:34 pm
by flip_normal
Usatracy on the Vis4V forum did this handy XM-2000 Motor Disassembly & Inspection manual for this motor, I think.

Re: Erato 2kw brushless hub motor help needed

Posted: May 30, 2008 7:33 pm
by The7
From this site, this motor has 10 pole-pairs and is a gearless hub.

Re: Erato 2kw brushless hub motor help needed

Posted: May 30, 2008 9:36 pm
by John in CR
USA Tracy,
Thank you so much. I found that site before, but didn't bookmark it and couldn't find it again.

7,
I know I'm a noob, but isn't a 20pole 3 phase motor impossible? Looking at the speed switch connections, I think the low speed / high torque setting causes each phase wire to connect to 6 of the coils. Then for the high speed setting, they connect only to half of the windings.

Now if I can just get it running and a large diameter tire, I could have a hill hog rocketbike.

John

Re: Erato 2kw brushless hub motor help needed

Posted: Sep 11, 2008 10:46 am
by John in CR
Oh Happy Day! Thanks to Knuckle's sensorless unit, my 2 speed Erato 2kw hubbie is up and running. This thing pushes an almost 300lb scooter to over 40mph, so imagine how it will perform on a bike weighing less than 100lbs and batteries that sag only to the mid 70's vs the 60V nominal of lead the scooter had. The shifter works like a charm, with the kV tripling when I twist the shift shaft to high speed. Before I get a wheel mounted on it and put it into service, I wonder if there's anything someone wants me to test while I have it on the rack. My thought is that with relatively minor modification to separate each phase connection into sub-groups, that any hub motor with a pole count in multiples could be turned into a 2 speed. I would extend the wiring to accomplish the switch needed for shifting outside of the hub. My only planned test so far is to get the no load current for both speed settings.

John

Re: 2kw 2 speed brushless hub motor

Posted: Oct 25, 2008 10:56 pm
by usatracy
It is an amazing little motor for what it is, we have gotten 45 mph out of it with the right tire.

With that said, I would actually slow it down to 41.5 mph top speed due to heat build up by using a SMALLER tire on the motor.

We have fielded dozens of bikes based on that motor controller in 48 and 60 volt versions, they are all used daily as dependable alternative transportation for folks and we have had ZERO problems, but we set them up for them, made sure the shifters were aligned and functioning properly, replaced the cheap thin rubber soft china tires with stiff rubber smaller Michelins.

That motor winding and shift design is unique in the industry, and it is STILL used today around the world, it is extremely inexpensive to produce and provides, via the shifter, two completely dirrent motor winding types, one for torque, one for speed.

That motor design is owned exclusively by Amoyee Chen of EFUN and is still offered on their line of bikes if one desires it, although most opt now for their 6 phase systems. But some importers still order this motor as there laws are much strictrer and they are not allowed to use the more powerful 6 phase offerings.

You can get 60 miles in low speed mode (22mph) on level ground using that motor and GreenSaver SP27-12 bats, I have done it several times.

The stock controller runs around 46 amps, but using a cycle analyst can be limite to 38 amp and the reduction in loss from Puekert effect on the batteries from this reduced amp load can greatly increase range without reducing top speed, although accel is effected a little as is hill climb.

Do not over heat motor or large power wires may desolder, the China solder on the power wires was not always that good, all of ours are resoldered prior to sale.

Do NOT shift the cup back and forth out of boredom, it flexes the wires and they can work break loose, same when very cold out, try not to shift a lot as the cold stiff wires will tend more to stress and may come loose.

PS go to

http://en.wikipedia.org/wiki/Brushless_DC_motor

and look at the image for delta and wye windings

I think this is what the shifter is doing, changing between delta and wye windings, but I am an idiot, what do I know ?

Re: 2kw 2 speed brushless hub motor

Posted: Oct 26, 2008 9:11 am
by ZapPat
usatracy wrote: I think this is what the shifter is doing, changing between delta and wye windings, but I am an idiot, what do I know ?
I think this is the ONLY way it could be done simply, so this makes it the first obvious conclusion. Others here on ES have wanted to do the same type of thing to regular brushless motors to get this same 2 speed effect. It would be very very easy to confirm this if you had one open if front of you.

Re: 2kw 2 speed brushless hub motor

Posted: Oct 26, 2008 10:06 am
by John in CR
ZapPat wrote:
usatracy wrote: I think this is what the shifter is doing, changing between delta and wye windings, but I am an idiot, what do I know ?
I think this is the ONLY way it could be done simply, so this makes it the first obvious conclusion. Others here on ES have wanted to do the same type of thing to regular brushless motors to get this same 2 speed effect. It would be very very easy to confirm this if you had one open if front of you.
Aren't the first 2 pics above enough to tell? They show the 2 positions of the shifting plate. I believe a better solution would be to have a larger diameter axle, bring the windings' connections outside the motor and handle the switching there.

John

Re: 2kw 2 speed brushless hub motor

Posted: Oct 26, 2008 11:15 am
by ZapPat
John in CR wrote:
ZapPat wrote:
usatracy wrote: I think this is what the shifter is doing, changing between delta and wye windings, but I am an idiot, what do I know ?
I think this is the ONLY way it could be done simply, so this makes it the first obvious conclusion. Others here on ES have wanted to do the same type of thing to regular brushless motors to get this same 2 speed effect. It would be very very easy to confirm this if you had one open if front of you.
Aren't the first 2 pics above enough to tell? They show the 2 positions of the shifting plate. I believe a better solution would be to have a larger diameter axle, bring the windings' connections outside the motor and handle the switching there.

John
Yes John, I would agree with you here about the larger axle + exterior switch being better than this potentially problematic setup, specially for me living in a cold country (from what tracy said about the wires breaking).

As for your delta/wye thing, I did it on paper and it looks to me like it would require two SPDT's + one SPST, or one DPDT + one SPST or something equivalent. Maybe hefty relays might do the trick? Hum...

Oh ya, about the photo being enough to figure out connections or not: Maybe a photo where we could see all the windings at once might help (straight overtop), but personnaly I would much prefer to have in my own hands to play with!

Re: 2kw 2 speed brushless hub motor

Posted: Oct 26, 2008 11:48 am
by John in CR
ZapPat,

Regarding what the switch does, and keep in mind I don't understand the difference in the 2 wiring configs you mentioned, what would be the effect of just disconnecting some of the coils. eg The motor has 18 coils making up the windings, 6 for each phase. When they're all in use you have a certain Kv (the low speed setting I assume), but what happens if you disconnect some with the switch?...say only 9 of the 18 are used (3 for each phase), or 6 of the 18 (2 for each phase). Does that increase the Kv?

Assuming that's how it works, what effect on max efficiency can we expect? Someone mention before % iron losses increase, but that was way over my head.

John

Re: 2kw 2 speed brushless hub motor

Posted: Oct 26, 2008 2:22 pm
by John in CR
ZapPat,

One other piece of info I noticed:

Cogging and cogging with phase wires shorted only changes in intensity with the high low switch. I'd think that if the winding changes that the cogging would change, ie change in the angle of each cog, if the switch was between delta and wye.

John

Re: 2kw 2 speed brushless hub motor

Posted: Oct 26, 2008 3:55 pm
by ZapPat
John in CR wrote:ZapPat,

Regarding what the switch does, and keep in mind I don't understand the difference in the 2 wiring configs you mentioned, what would be the effect of just disconnecting some of the coils. eg The motor has 18 coils making up the windings, 6 for each phase. When they're all in use you have a certain Kv (the low speed setting I assume), but what happens if you disconnect some with the switch?...say only 9 of the 18 are used (3 for each phase), or 6 of the 18 (2 for each phase). Does that increase the Kv?

Assuming that's how it works, what effect on max efficiency can we expect? Someone mention before % iron losses increase, but that was way over my head.

John
I would guess the Kv would increase by two since the coils would be half as long, but you would have only half your poles working which I can't see as being any good at all. I would definitely go the wye/delta switch way instead to keep all the poles and copper active.

Here's a quick diagram of what could see working, but no doubt there could be a few variants on this.
wye-delta motor switch - small.gif
wye-delta motor switch - small.gif (43.01 KiB) Viewed 5574 times

Re: 2kw 2 speed brushless hub motor

Posted: Oct 26, 2008 4:11 pm
by ZapPat
John in CR wrote:ZapPat,

One other piece of info I noticed:

Cogging and cogging with phase wires shorted only changes in intensity with the high low switch. I'd think that if the winding changes that the cogging would change, ie change in the angle of each cog, if the switch was between delta and wye.

John
Once again, I'm no motor expert but I couldn't see why the cogging would change between wye and delta. I think cogging is characterised by the electromagnet / magnet pole combination used. Also, most controllers can drive either wye or delta motors without noticing the difference.

As for the change in shorted cogging intensity when changing the motor's switch, this would make sense as you are producing more voltage with one configuration than the other, thus giving more resistance to turning while shorted like this. This would be great to have to make regen more efficient! And then combine such a motor with a switchable series/parallel battery setup and you would have something resembling 4 gears to play with! Great for low speed torque, higher top speed, and better regen efficiencies... yum!

BTW, do you notice any real difference in the cogging with phases not shorted between the two motor settings? Or only when the phases are shorted together?

Re: 2kw 2 speed brushless hub motor

Posted: Oct 26, 2008 4:19 pm
by johnrobholmes
The magnetic detents will be the same with any wind pattern. The shorted phase drag (drag brake) will become more intense with a lower KV termination.

Re: 2kw 2 speed brushless hub motor

Posted: Oct 27, 2008 5:20 am
by rkosiorek
it can be done with a single 3PDT or 3 large individual SPDT relays and an external switch. the problem is to find relays with contacts big enough but yet physically small enough to fit inside of the motor housing.

this technique is used on many industrial 3 phase motors to give 2 speeds. in some cases the motor will start in the star configuration for high torque and a centrifugal switch will change over to delta once a certain speed is reached.

rick

Re: 2kw 2 speed brushless hub motor

Posted: Dec 15, 2010 6:13 am
by viking01
Hi, good reading, but you may have a few point wrong. I have a complete 2000w, 60 volt scooter from 2007 new. The point about 2 speed switching is also base on the controler. I did have 2 speed switching when new but I change the controler for a direct power unit and this the scooter now beats a lot 125c upto 20mph and I still have a top speed on flat road of 47mph on a GPS. The new controller has a lot more parts in side: 8 fet etc. and 410gram heaver. The batteries are lead/jell, 5x12x30anp

rei

Re: 2kw 2 speed brushless hub motor

Posted: Dec 15, 2010 7:07 am
by Jeremy Harris
viking01 wrote:Hi, good reading, but you may have a few point wrong. I have a complete 2000w, 60 volt scooter from 2007 new. The point about 2 speed switching is also base on the controler. I did have 2 speed switching when new but I change the controler for a direct power unit and this the scooter now beats a lot 125c upto 20mph and I still have a top speed on flat road of 47mph on a GPS. The new controller has a lot more parts in side: 8 fet etc. and 410gram heaver. The batteries are lead/jell, 5x12x30anp

rei
Not true in this case, they don't have any points wrong. Brushless motors can be switched from delta to wye, changing their Kv, without needing to do anything to the controller at all. It's just a matter of re-arranging the way the three windings in the motor are connected, that's all.

There's no need for a new controller, additional FETs, or anything else you have mentioned in order to make a delta/wye switched motor work in this way.

Jeremy

Re: 2kw 2 speed brushless hub motor

Posted: Dec 15, 2010 3:55 pm
by John in CR
Dredged up an old one. This was the motor of mine that LFP took a gander at when he was down here. The process I started to lighten it, ventilate it, take it to crazy power, and use it as a mid drive is discussed here https://endless-sphere.com/forums/viewto ... er#p255181. That was all before my machine shop buddy chocked it on his big lathe incorrectly and crunched some some of magnets. It's an impressive stator that will get a new ventilated rotor, but to run the big power, that internal switching will have to go, because no way those contacts can handle a lot more power. Six wires to the outside and big contactors is the answer....Just waiting on the gurus come up with he-man controllers. What good is a cheap 20kw outrunner if the only controller options are several $k ?