motors

[anthony_starke]

Does anyone know any of the tech specs on the motor used in the segway ht? (volts/amps/etc)

I know it has some slick features, but what are the plain jane type stats on them?

[Dragan]

I thought I had some tech specs on them, but I can't find them. They are dual parallel wind brushless, meodymium-iron-boron magnets.They're made by pacific Scientific (a division of Danaher)and are stated to be the highest power motor for their size and wieght ever put into mass production.

Hope this helps!
Wayne
www.mysegway.ca

[Stan671]

Segway considers these motors to be thier Intellectual Property and probably won't give out many details. That is why there were none available at the V1 Memorabelia sale.

This link is Segway's description of the motors:
http://www.segway.com/segway/component_details.html

Stan Dobrowski

[W9GFO]

quote:they are the highest-power motors for their size and weight ever put into mass production. Each motor is capable of maintaining a power output of 1.5 kilowatts--that's 2 horsepower!

There are RC brushless motors out there that can put out similar power that are considerably smaller than the HT motors. Since all it takes is a credit card to get one of them I would consider them mass produced, heck, there's probably more of them than HT motors!

Maybe not.

Rich H

The Un-Official Segway Battery FAQ
http://www.spinfoot.com/SegwayBatteryFAQ.html

[Stan671]

Rich, can you provide me with a link or two to such motors?

I don't think you are refering to the same kind of motor that is in the Segway HT. The HT's DC servo motors, which run on 72 volts (I think?) and max out at 8,000+ RPM, are more like stepper motors than traditional motors.

I quick search of tower hobby's web site shows the most expensive ($270) brushless motor (Novak HV-Maxx Brushless Motor System) with a power output of 375 watts @ 14.4V. I think this is just a different kind of motor than in the HT.
http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXBLB8&P=ML

Stan Dobrowski

[anthony_starke]

W9GFO,

Any links on those RC motors?

[KSagal]

Okay,

I'll bite. Just what is the Horsepower in a seg motor?

Also, is wattage the same as power output? I thought it was power input...

Kind of like the wattage of a bulb, We can assume that most 100 watt bulbs generate more light than most 60 watt bulbs, but I know that all 100 watt bulbs do not put out the same lumens.

Wouldn't it be possible for two different 375 watt motors at a given voltage have different power outputs for the same size input?

I have personally seen the different outputs of a 4.75 litre ford engine compared to the same displacement porche engine... Enough examples...

Please someone educate me....



Karl Ian Sagal

Each road you travel should be just a bit better for having had you pass.

[W9GFO]

quote:Originally posted by Stan671

Rich, can you provide me with a link or two to such motors?

I don't think you are refering to the same kind of motor that is in the Segway HT. The HT's DC servo motors, which run on 72 volts (I think?) and max out at 8,000+ RPM, are more like stepper motors than traditional motors.
The HT's brushless motors are like steppers only in that both types are brushless. A normal DC motor has permanent magnets on the outside and field coils on the rotating portion. The field is alternated by means of the commutator (brushes). On a brushless motor things are reversed - the permanent magnet is the rotating part and the magnetic field is on the outside, controlled by a special controller so that it alternates polarity at the appropriate time. Brushless motors have three leads, steppers can have four, five, six or eight. The HT's motors probably have six leads because each motor unit is wound as two separate motors sharing a common shaft.

Here's a link to a motor capable of putting out over 1,500 watts and is only 1.5" long.
http://www.megamotorusa.com/shopping/..%5CBrushless%5CACn22-20-3H.htm?id=24

Rich H

The Un-Official Segway Battery FAQ
http://www.spinfoot.com/SegwayBatteryFAQ.html

[W9GFO]

quote:Originally posted by KSagal



Wouldn't it be possible for two different 375 watt motors at a given voltage have different power outputs for the same size input?

Certainly would be possible. Each motor is designed to be most efficient at a certain voltage. Take a 375 watt motor designed for 12 volts and run it at 24 volts and it's output is going to be more than 375 watts, will probably overheat too.

V * Amps = watts

1 HP = 746 watts = 33,000 ft-lbs work per minute.

Expect most good motors to be 90% efficient. So 1000 watts in equals 900 watts out and 100 watts heat.

Segway HT motors are 1500 watts at 72 volts ~ 20 amps. Or 10 amps per half motor since each motor is wound as two. In normal operation the motors are drawing around 3 amps or less.

Rich H

The Un-Official Segway Battery FAQ
http://www.spinfoot.com/SegwayBatteryFAQ.html

[Dragan]

I'm missing something here...I fly RC helicopters (and not little ones, rotor diameter close to 6 feet), use brushless motors, li-Poly batteries, and there is no way any heli brushless motor is putting out the kind of raw power that the segway motors do. Brushless are voltage dependant; the more battery you apply, the more power you generate, to a point. The seg's motors are limited RPM, more like a servo motor, and generate greater torque as opposed to high RPM rates. What am I not understanding?????????
Wayne

[W9GFO]

quote:Originally posted by Dragan

I'm missing something here...I fly RC helicopters (and not little ones, rotor diameter close to 6 feet), use brushless motors, li-Poly batteries, and there is no way any heli brushless motor is putting out the kind of raw power that the segway motors do. Brushless are voltage dependant; the more battery you apply, the more power you generate, to a point. The seg's motors are limited RPM, more like a servo motor, and generate greater torque as opposed to high RPM rates. What am I not understanding?????????
Wayne

Why do you say the HT motors are RPM limited? Sure, they are wound for lower rpm/higher torque but rip those suckers out and run them on 120 volts and they'll turn faster for sure.

I'm sure that "raw power" of the HT is observed because of the very high torque and relatively low speed that it can turn the wheels. I'm confident that your electric heli's raw power can be experienced as well, but at higher rpms.

Undoubtedly the HT will put out more torque. But that is not power. Power is the rate of doing work.

Rich H

The Un-Official Segway Battery FAQ
http://www.spinfoot.com/SegwayBatteryFAQ.html

[Dragan]

I said they were RPM limited because they are; mounted in a Segway, they are limited in RPM by virtue of the manner in which they are wound, and the fact that you have a finite number of battery cells providing energy to the motors. I also said that by applying more energy through more battery (voltage) you increase output to a point. The point I was trying to make is that from a size and weight perspective, I've never seen a helicopter motor of any size generate the kind of torque that the Segway motors generate.
Wayne

www.mysegway.ca

[W9GFO]

quote:Originally posted by DraganThe point I was trying to make is that from a size and weight perspective, I've never seen a helicopter motor of any size generate the kind of torque that the Segway motors generate.

But the torque you are seeing with the Segway is after a gear reduction. You can always trade rpms for torque. That little helicopter motor, if put through a gearbox, could generate just as much torque.

My point is that there are some damn powerful little motors out there. The HT motors, as nifty as they are, are not the ultimate in power to weight ratio (or physical dimensions) for electric motors.

Rich H

The Un-Official Segway Battery FAQ
http://www.spinfoot.com/SegwayBatteryFAQ.html

[Dragan]

you do use a gearbox on helis, quite sophisticated in some cases, since you also have to drive the tail rotor at the same ratio as the main rotor. I understand what you're saying, all I'm getting at is the Seg motors are pushing a lot more mass along the ground (in excess of 200 lbs on average) the the heli motor lifts (10-15 lbs in extreme cases).

There may well be motors that are capable under sepcific circumstances of exceeding the output of the Segways motors, but heli motors aren't, at least none that I've ever seen or used

[W9GFO]

Ok, so the electric motor that you use in your heli is not as powerful as the HT motor. That's probably true. I use a small brushless motor in one of my RC helis and it is not as powerful as an HT's.

The motor I provided a link to can handle up to 70 amps with 24 cells. That's up to 2 Kw or 2.7 HP and it is far smaller than an HT motor. The rpm would be very high for sure but if geared down would be capable of producing much more torque than the HT motor could. It is simply more powerful - and smaller.
quote:all I'm getting at is the Seg motors are pushing a lot more mass along the ground (in excess of 200 lbs on average) the the heli motor lifts (10-15 lbs in extreme cases).
The HT uses 430 watt-hour batteries (currently) and will use it up in about one hour (43 w/h every six minutes). My electric heli uses 36 w/h batteries and will only last about 6 minutes. So the one little motor in my heli is operating at almost the same power level as both HT motors. It takes a lot of energy to hover, even a lightweight RC heli.

Rich H

The Un-Official Segway Battery FAQ
http://www.spinfoot.com/SegwayBatteryFAQ.html

[Doug Field]

Be careful about looking at volts and amps for your calculations--that's power in, not out, and no motor is anywhere near 100% efficient, especially at these currents. Know how hot the batteries and motor get after a flight? That heat has to be subtracted from VA power calculations. Multiplying the battery voltage and current is not a great way to actually determine shaft power, since there's no knowledge of where in the efficiency curve the motor is operating.

The HT motors can put out 2000 Watts mechanical shaft power--4 N-m at anout 5000 RPM. This is power out, not in. I don't know of an RC motor anywhere near these output levels, probably because the size of the craft that could be lifted would arouse a lot of interest from the FAA. It would make a good target drone.

The design parameters are also quite different for an HT--peak power is required for safety (responding to bumps and other transients) and continuous power is typically very low (a few hundred watts at cruise) compared to peak. RC helicopters need to run at or near peak power most of the time--they have a near-even peak-to-continuous ratio.

Also, from a life standpoint, consider how many hours you are actually logging on that motor before you'd expect it to be replaced. We have machines in the field with over 3000 hours with no need to even consider motor replacement. If your flights last ten minutes, 3000 hours is 18,000 flights, or one per day for 50 years.

We have lots of engineers on the team who enjoy electric RC aircraft. You'll see several in the air outside the plant at lunch on nice days. In many RC aircraft it's actually the battery that's limiting the power output of the system, not the motor. But matching the two together is key to efficiency--getting most of those Volt-Amps turned into shaft power.

"There is nothing more difficult to take in hand, or more perilous to conduct, or more uncertain in its outcome, than to take the lead in the introduction of a new order of things." -Niccolo Machiavelli

[sholloway]

Anthony be careful. This "Doug Field" character has been lurking around here for quite a while although he almost never posts. You may want to double check his facts. I would try and check with the Chief Technology Officer or the Vice President of Design and Engineering if I were you! :)
Thanx Doug, for taking your time to read and/or post here. It's really nice.