12 kw rc motor

[markobetti]

20 POLES, DON KNOW HOW MANY MAGS . I WILLL CHECK.

[Jeremy Harris]

Sounds very good, Marko. I'm seriously thinking about resurrecting my light motorcycle project. It's been on hold for several reasons, one being the problem of getting enough batteries in it with the big Mars motor and Alltrax controller. This motor looks to be the same, or maybe more, power than the Mars and I know I can make a controller much smaller than the Alltrax. I reckon I could lose about 20 - 25kg of weight off the bike by using this motor, even if I do need to add another reduction stage.

I'm looking forward to hearing how Hal gets on with it, if all looks OK I will PM you to add my name to the list. I may buy either one or two motors, depending on how they perform.

Jeremy

[markobetti]

only 5 orders motors on pm. with mine it is 7. Well guys i dont think we are going to make 30 pcs ..

[markobetti]

yep , motorcycle coversion sounds great , and on one shaft and two controllers there should not be loss of efficiency , and hell ; they would look great if somebody likes eye candy like me

[markobetti]

hals version will bring out the monster from the monster , i am seriously thinking about naming him hals HULK and making him with anonized green color how about it hal?

[12p3phPMDC]

It's probably the lack of test data holding things up.

I've got a Turnigy 100A controller I'd be willing to help out with.

Freight to Europe would be expensive.

It wouldn't support this motor to full power though.

I'm thinking we need a 200A 100V controller for this beast.

[swbluto]

Do you know where the technical specs are? Kv, no-load current at some mentioned voltage, and the motor's resistance would be nice. All but kv are easy to measure with a power supply and voltmeter, and I can explain it if you'd like.

[markobetti]

all right . This is all info i have : .the RPM of motor is 750. the idle current is 8.6A when we use the 12V voltage to test it - manufacturer

URL=http://img291.imageshack.us/i/infoo.jpg/][/URL]

i cannot confirm anything except that the motor construction is great. Still waiting for sensorless controller for test

[markobetti]

[markobetti]

Jeremy what is your conclusion based on parameters ?

[liveforphysics]

You're not going to find a sensorless controller to do it any justice.

There isn't a sensorless controller available that can even do the 1/3rd the size HXT motor any justice.

Get one of those motors to Jeremy or Burtie, and they can figure out a sensor position/solution for it, and then it can be used properly.

RC controllers are for toy motors in 10lbs toys. This is not a toy motor.


As far as the people asking about bigger phase leads, that would just require doing a higher KV wind. They just pair the phase wires up in delta and run them out of the case on RC motors, so the wire size is determined by the winding dimensions, which are of course determined by the number of winds.

[swbluto]

The following quoted text might be wrong. I have a feeling I ignored the squared relationship between kv and resistance which may be applicable here...

The resistance looks pretty low for the kV. An HXT motor has a resistance of 27 mOhm at a kV of 130, so this motor would imply (130/75)*(27/10) = 4.68 times the copper fill of the HXT 130 kV motor. Must be hefty!

The graph was derived with 12 volts and no current limiting (Which would be unrealistic as you'd have to employ motor current limiting at the bottom end as the 3000+ amps as would be implied by 36 volts would be a little ridiculous.):

Untitled.gif (60.29 KiB) Viewed 625 times

At 12 volts, the efficiency peaks at 85%. As with most motors, its efficiency will probably increase with higher voltages so based on comparisons to agni and hxt, I might expect its efficiency to peak at 92-95% at higher voltages like 60 volts.

As you notice, the amps with this "no limits" simulation is 1100, so motor current limiting would probably be used in real life and the bottom half of the graph would be kind of unrealistic. Looking at the graph, it looks like 300 motor amps would correspond to a starting torque of 39 N.M.; With an 8:1 reduction, you're looking at 312 N.M. at the wheel which is definitely appreciable.

As far as this goes, I definitely think a sensored controller would be realistic. The inherent error involved with sensorless is fine with lower powers, but it results in huge wasted power at higher power levels in a varying load application = needs a beefier controller. As far as I know, I haven't found true high power sensorless controllers other than RC controllers.

[Jeremy Harris]

Marko,

Looking at those figures, Io (the motor no-load current) seems to be a little high at 8.6A. It may be that this is related to the way the test was done, or perhaps, just an error.

Is this data from Hal or is it from the manufacturer? My experience with Chinese motors is that the specifications are often a bit garbled, possibly as a result of language problems. For example, one motor I bought had a stated Io of 3.6 amps, yet when I put it on the bench and tested it I found that it varied between 0.8A and 2A over the full voltage range.

The winding resistance, Rm, looks pretty good at 0.01 ohms though, the motor looks able to handle the current OK for short periods, although the I²R losses at 200 amps will be around 400 watts, so it will need some cooling. At a guess I'd suggest that the continuous power rating should be around half this (maybe around 140 amps), but that's still pretty good and a lot better than the nearest big, cheap outrunner.

For comparison, the HXT 80-100 130Kv, 6500 watt motor has an Io of 2A, an Rm of 0.032 ohms. At it's maximum voltage of 48V and max power of 6500 watts it will draw 135 amps and have I²R losses of over 580 watts, so far less efficient. There's no way the HXT motor will sustain 135 amps, either, my guess is that it'd get pretty warm if run at more than about 50 amps continuously. On bikes it's hard to draw currents of over 100 amps for long, though, at least on the road, so the average current is likely to be a lot lower, which is why people aren't burning these motors out. This big motor will be even better, as it looks like it should be able to run at maybe three times the continuous power of the HXT.

As soon as we hear from Hal I'll PM you, Marko.

Jeremy

[markobetti]

No ,this is manufacturers data. Hal and i didnt test it , because controller burned No problem , i think i will ask Hal to help with this order . Heat will be no problem since Hal has figured out a way to cool it if it will be needed . Jeremey thanks for reply and others. It looks as this motor is a real deal, also i have no doubt in Hals idea since the way he will cool it is very promising . One thing about this motor, it doesn't lack the space for modding unlike other outrunners . In two weeks i should get the sensored motor . For me the only thing that is bothering me is not the power of motor ,or cooling , but the direct drive . i am designing a frame for dd , and if it will not be possible dd i will have to redesign the frame ..

[markobetti]

the exact weight of the motor is 5.2kg

[Jeremy Harris]

You're not going to find a sensorless controller to do it any justice.

There isn't a sensorless controller available that can even do the 1/3rd the size HXT motor any justice.

Get one of those motors to Jeremy or Burtie, and they can figure out a sensor position/solution for it, and then it can be used properly.

RC controllers are for toy motors in 10lbs toys. This is not a toy motor.


As far as the people asking about bigger phase leads, that would just require doing a higher KV wind. They just pair the phase wires up in delta and run them out of the case on RC motors, so the wire size is determined by the winding dimensions, which are of course determined by the number of winds.

I'm already working on a controller, Luke! I've been doing a lot of work recently on building a small, high current, controller. One thing I discovered, when looking through dozens of FET spec sheets, is that there are some surprises, as a big package isn't necessarily the best. Some may have spotted that getting heat out of the FET junction is the big issue that limits the current a single FET can handle. There's nothing much that can be done about the internal thermal resistance, and this tends to be similar for pretty much any package. The big packages offer the means to get heat out of the package more easily, but this can be done another way, I think.

I've found this FET:

IRFS3107-7ppbf.pdf

(315.27 KiB) Downloaded 230 times

Yes, it's a small, surface mount package. BUT, look at the ratings and then think about this as a mounting option:

What if the power rails and the phase connections were solid copper bars, connected to internal finned heatsinks?

What if the FETs were soldered directly to the copper bars, providing not only a good electrical connection, but also a near-zero thermal resistance (no insulators needed)?

What if the controller had a small internal fan to keep the "live" heatsinks cool?

I'm thinking of a 12 FET power "board" using these FETs, driven by a 6 FET controller board. I reckon such a controller would comfortably handle well over 200 amps. In fact, in might well do around 150 amps on just 6 FETs. The downside would be the 75V FET Vds limit, but as the motor is rated at 60V max this shouldn't be too big and issue.

Any thoughts?

Jeremy

[bigmoose]

Jeremy your idea is good! It is exactly the direction I was headed, and I was spec'ing the D2Pak 7Pin package also. As they say, "Carry on!"

I was looking at the 100 Volt version: IRFS4010.

An other facet I was thinking about was to remove all the spaghetti from the "power head" of the controller and run a serial link to a handlebar "data/control module" That way the PowerHead only get battery busses, 3 phases to motor, hall leads, and a 3 or 4 wire link to the DataControl module. All the rest of the spaghetti/connectors would then be right in the handlebar area.

[jag]

What if the power rails and the phase connections were solid copper bars, connected to internal finned heatsinks?

What if the FETs were soldered directly to the copper bars, providing not only a good electrical connection, but also a near-zero thermal resistance (no insulators needed)?

What if the controller had a small internal fan to keep the "live" heatsinks cool?

I'd say solder thick and wide copper power bus to source and drain (ben the gate up a bit). Then a thin insulating sheet between the copper bars and a regular passive heatsink. Remember total thermal resistance of this insulating sheet = k/contact area. the contact area of the copper bars can be made arbitrary large, so the negative impact of an electrically insulating pad can be made much smaller than when it is attached directly to the FET. This is why newer CPU's have heat spreaders inside the package.

Even more compact: Design the controller PCB to match the slightly bent up gate pins, then attach power bar and heatsink assembly with small risers. A bit of a pain to manually solder the FETs this way, but I think I have managed more tedious ones...

[12p3phPMDC]

THose 7 lead d2paks do look impressive. lots of good ideas here.

Keystone electronics makes some great little phenolic standoffs with threads that you can use
to isolate a direct copper bonded assembly if you want to float it within the case.

I just got some samples to isolate the ground leg of the shunt from the heat sink.

[swbluto]

You're not going to find a sensorless controller to do it any justice.

There isn't a sensorless controller available that can even do the 1/3rd the size HXT motor any justice.

Get one of those motors to Jeremy or Burtie, and they can figure out a sensor position/solution for it, and then it can be used properly.

RC controllers are for toy motors in 10lbs toys. This is not a toy motor.


As far as the people asking about bigger phase leads, that would just require doing a higher KV wind. They just pair the phase wires up in delta and run them out of the case on RC motors, so the wire size is determined by the winding dimensions, which are of course determined by the number of winds.

I'm already working on a controller, Luke! I've been doing a lot of work recently on building a small, high current, controller. One thing I discovered, when looking through dozens of FET spec sheets, is that there are some surprises, as a big package isn't necessarily the best. Some may have spotted that getting heat out of the FET junction is the big issue that limits the current a single FET can handle. There's nothing much that can be done about the internal thermal resistance, and this tends to be similar for pretty much any package. The big packages offer the means to get heat out of the package more easily, but this can be done another way, I think.

I've found this FET:

IRFS3107-7ppbf.pdf

Yes, it's a small, surface mount package. BUT, look at the ratings and then think about this as a mounting option:

What if the power rails and the phase connections were solid copper bars, connected to internal finned heatsinks?

What if the FETs were soldered directly to the copper bars, providing not only a good electrical connection, but also a near-zero thermal resistance (no insulators needed)?

What if the controller had a small internal fan to keep the "live" heatsinks cool?

I'm thinking of a 12 FET power "board" using these FETs, driven by a 6 FET controller board. I reckon such a controller would comfortably handle well over 200 amps. In fact, in might well do around 150 amps on just 6 FETs. The downside would be the 75V FET Vds limit, but as the motor is rated at 60V max this shouldn't be too big and issue.

Any thoughts?

Jeremy

If you can successfully mount/solder it to a large heatsink without killing the fet AND have a powerful fan providing airflow, I'd say you got yourself a winner. I use a CPU fan with heatsink on my ESC and it stays *amazingly* cooler when blowing air than when it isn't. (Like the difference between 10 degrees above ambient and 130 degrees.) The closer the air flow is to the fets, the better.

[Jeremy Harris]

I guess I could bolt the big copper bus bars to an external heatsink, using insulating pads, but I rather like the idea of internal fan cooling. I think this motor is probably going to need forced air cooling if it's run enclosed/semi enclosed on a bike, anyway. One option might be to build the controller into the motor mounting housing, fit a fan on the end of the motor and have a neat unit that houses the motor, controller and something like one of Matt's reduction drives.

This would make installation and wiring nice and easy and it would reduce the I²R losses on the controller to motor phase wires (which can be high, as the phase current peak can easily be two or three times the battery current). A module that just bolts in, with a drive shaft suitable for direct connection to a final drive on one side, a couple of hefty power feed wires, a three wire throttle connection and maybe an ebrake connection would make for an easy to use power unit. Using the motor as the means to turn the fan removes the potential unreliability of a separate cooling fan.

Whilst I can probably put together the controller and maybe prototype the drive module, if it works it might be just the sort of this for one of our budding parts producers to look at making. It'd be nice to have a CNC machined housing holding everything and looking cool as well.

Jeremy

[Timma2500]

Wholly snapping duck shit i MUST have one of these beauties!!! Luke forgets about
160km/hr e-bike 200km/hr babeee! Lets see those frock motor boys catch this bad boy

Who do I paypal?
.

^^Ditto

KiM

Yep that pretty much sums it up! Hmmm single speed, direct drive to back wheel with maybe around 3:1 - 5:1 reduction depending on voltage used.
Simple, neat, monstrous!
Awsome find! Now to find a controller with big enough balls to run it lol
Sounds like work has began on that front


Paul

[markobetti]

i will have sensored - same motor on 14 of april

[12p3phPMDC]

Markobetti,

Fantastic!!

If you can request that all of the motors we want to be sensored for little to no cost extra, then that would
make it generic for everyone, because if you find a monster sensorless controller, you don't have to use the sensors anyway.

[swbluto]

If you can request that all of the motors we want to be sensored for little to no cost extra, then that would
make it generic for everyone, because if you find a monster sensorless controller, you don't have to use the sensors anyway.

Yep yep. I'd gladly pay more for the option to use hall sensors, if I wished. If I didn't want to use hall sensors, sensorless is pretty straightforward and is a small price to pay for the majority who want sensors.