Printable View
Anyone had any experience with these motors (with / without planetary gearbox)? Are they reliable - anyone seen the tech / performance specs for them etc.? Any gotchas?? Their website is pretty unhelpful! Am thinking of dusting off the grinder and building a mini-DisConstructor, and these motors look interesting!
just looked on your website bloody hell you had 2 lems for drive and a lem for disc bet that one hell of a powerful bot
Astros are brill motors if used correctly, two for a weapon would be brill (Geoff Smith will know more about that :)). They are also great as drive motors with the gearsets that you can buy, (also... Geoff! well Karoline & co will also know). Problem is battery drain with so many brill motors though...
not a big fan of them. We used one in typhoon cadet in san fran. Burnt out in its first match. The resins inside the motor had melted and then the motor seized completely.
They are good motors but remember that to produce 1hp from such a small package you need a large amount of cooling because it doesnt have enough mass to do it effectively itself.
We got just as good performance from a normal drill motor (18v on 24v)
Ok, I heard someone was taking my name in vain!!
Mike,
Astroflight 40s..So were do you want to start?
I could write a dissertation on he pros and cons of this motor, we have 6 (soon to be 10) of these things spread across our feathers.
The 15:1 planetary g/box (model 940P)is a truly superb traction motor check outhttp://www.pillowtorque.com/tech.htmhttp://www.pillowtorque.com/tech.htm for an example of an extreme featherweight drive train. Also take a look at http://www.pillowtorque.com/pillow_fight.htmhttp://www.pillowtorque.com/pillow_fight.htm for a twin motor application using the model 40 motor without the g/box as a spinner drive.
The 940P is a very rugged drive unit but requires mounting properly using the four M4 tapped holes in the face of the gearbox and for best results the motor supported too.
The 12mm output shaft, although quite capable of having a wheel mounted directly to this shaft there is a possible issue with long term repeated shock loads weakening the front bearing. We have found that this can be avoided by using a separate axle for wheel support driven by a belt/chain from a pully/sprocket mounted on the gearbox. (see Pillow Torque) Mounted like this they are entirely reliable, we have had the same units in Pillow Torque for the better part of 2 years completing over 125 fights (mostly at 100% duty) plus many hours of testing and only now are we replacing the motor brushes and repacking the gearbox with new grease. Other than that they have had no maintenance whatsoever. As Gary points out that due to the silly amounts of power they can deliver they do produce a lot of heat, which at first seems quite worrying but we have learned that these motors are quite happy to run at 100 C all day!BUT and its a BIG BUT if you are using the motor alone as a weapons drive, then gear ratio is CRITICAL. These motors run at around 16,300RPM @ 24V We have found that a reduction ratio of a MINIMUM of 3:1 is required to prevent the heat build-up eventually melting the whole thing (ask Ewan what happens to them at 2:1!!) I would prefer a ratio of 4-4.5:1 for peace of mind.
If you want dimensions for the 940P they are herehttp://www.teamwhyachi.com/misc/A40P.pdfhttp://www.teamwhyachi.com/misc/A40P.pdfthe full spec. of the motor alone is here http://www.robotcombat.com/marketplace_astroflight.htmlhttp://www.robotcombat.com/marketplace_astroflight.html You may also want to check out these alternative gear boxes http://www.teamwhyachi.com/Twa40.htmhttp://www.teamwhyachi.com/Twa40.htm
Both Team Whyachi and Robot combat are good sources of the motors and will happily ship to the UK .
If you want any further info e-mail me teamscorpion@aol.com and Ill try to help.
Regards,
Geoff.
Thats what took so long to hear from Geoff about Astros.
He did a bloody essay. :proud:
Mr Stu
What do you mean essay...thats the SHORT version!! :)
Many thanks for feedback - all very helpful. Gary - one question after your meltdown...was the motor repairable?
eh definately no!
The motor turned fine immediatly after we removed it but once it had cooled, the resins inside hardened again and the motor was non repairable. An expensive mistake!
I would possibly advise a heatsink and or fan beside one if you are going to run one.
Personally I would never use them again, too easy to nacker.
Did you throw the motor gary? if not, i wouldnt mind it?
Grant we didnt throw it. I am afraid its not for sale. Just one of those little tinkets we will be keeping to remind us of our combat days.
Are you sure :sad: u got the whole robot to remind you :sad: lol. No probs though.
Just a notice, if anybody has burned out/broken astros that you are about to throw, keep a holof them, i may be intrested in them for replacement parts.
just out of interest does anybody know what speed an astro 40 with the 1.7 : 1 gearbox run on 14.4v would be? cheers
You just being lazy James ?
http://www.astroflight.comwww.astroflight.com tells you speed/volt = 682rpm/v
So 682 x 14.4v = 9820rpm
Put that through a 1.7:1 gear box and you get
9829 / 1.7 = 5776rpm (unloaded speed).
Hardly rocket science - I thought you knew how to build robots ;o) ?
Ed
http://www.teamstorm.comhttp://www.teamstorm.com
Mee Oww!! :wink:
Ed does has a point there :)
Astro + 1.7:1 reduction + reasonable load = 1 bloody hot Astro!! (even @ 14.4V!) :lame:
thanks guys. didnt know how acurate that rpm per volt equation is as i wouldnt of thought it would be an equal rise between the voltages. increased heat and all that gubbins may play a role in slowing the increase to speed down as the rpm goes up? guess not lol
geoff i plan to add another 2:1 on it. hopefully it wont burnt out.
On another point do you know how good the astro 25s are at takeing load? hopeing to use one in the selfrighting arms.
1.7:1 X 2:1 = 3.4:1... I wouldnt want to go any less than that for something like a spinner drive.
As for the 25s, had no dealings with them.. sorry.
ye im actualy after a 3:1 or 2.5:1 reduction but RS only do the 2:1 bevel gears.
the astro 25 would be geared down 30:1 then attached to a thread which will make the arms move. it may come close to stall as the arms are on a 10:1 leverage?
30:1 on an astro 25? very fast that, 100:1 on standard 540 motor is about the same torque but a lot less cash. (without doing any maths on torque im making an educated guess).) i have some of these for sale if you think they might be suitable.
as to the spinner, listen carefully to geoff and john from scorpion, i am sure nobody in the uk knows more about these in this application, and problems that occur as a result. shame you gave up on the nitro engine though
James, I dont know what kind of calculations or system youve done but 30:1 seems small for a lifter. As an example we use 900:1 on Big Nipper, ok its not on a lever but still stalls the motor when 2 or 3 robots get on it, to help we also current limit the motor. Also running an astro near stall for more than a few seconds will destroy it so be careful when you test it or use a current limiter.
speaking of which, for the weapon and arm motors, why not buy a sidewinder? perfect for this job eh?
send me some specs james.
ye the nitro engine was just far too unreliable.... real shame :sad: besides i doubt many events could run an engine safely as if the feul cought fire you wouldnt see it burn easily.
the gearbox on Venom is 22.5:1 which works out at 355rpm and that is a nice speed. the arms on predator have a 10:1 disadvantage which speeds them up again. i did work out the power in the arms, it was good for selfrighting. 30:1 works out at 466rpm i think which should raise the arms in 3 secs.
all specs for sidewinder on http://www.robotpower.comwww.robotpower.com
prices around £250
specs for 100:1 motor
voltage 4.5V 6V 9V 12V 15V
100:1 rpm 35 50 77 103 134
prices £20 each
email me if interested
we run our 3kg disk on a 940astro at 14.4v. Also fitted a cpu cooling fan above the motor. Pulley ratio is 3:1 giving a tested max rpm of 3150. No problems with overheating so far.
Rob
thats 9450 rpm at the motor rob.
defies physics, or your batteries are giving a lot more than 14.4v
with any kind of teeth, or any kind of mass, a realistic maximum you can expect is 66% of no load speed (this varies a lot but is a ball park figure.)
for 14.4v, to get 3150 on a 3:1 ratio, you must have zero air resistance, zero transmission resistance, and measure it after an hour of spin up starting. I would suggest your rpm meter is inaccurate Rob, or your batts are amazing and produce a lot more than 14.4v
or astrolight have varying rpm/v specs, or any one of a thousand reasons, but as is cant happen
dunno james, ive used the rpm meter for a couple of years and i think its ok but it could be wrong. can a pair of gp 3300 mAh 7.2v cells deliver much more than 14.4v, doubt it. its probably the battered old rpm meter. ill get the strobe on it next week.
rob
you can expect as much at 16v plus from good barreries labled 14.4v, but still, seems too high.
i get 8.6v out of my 7.2v Nimhs easy and thats not directly after chargeing. 16v for 2 packs i would not be happy with.
which assuming no friction anywhere in the system and no voltage drop under load gives 3910rpm at 17.2v
meaning for the calculation to still work, loosing no voltage at all (defying physics again) the gearbox, air resistance, and assuming the disk has 1 hour to spin up, means you cannot be less than 80% efficient.
still doesnt add up, but glad your batts are so good JC, at that rate you batts would have 43v instead of the rated 36v
nice
My 19.2V NimH pack (16 cells)is standard 22.3V - 22.4V, even after 3 fights in a row it doesnt go below 20V.
We tested little spinner with an rpm meter and got 2050rpm after a few seconds, which worked out to be around the no load speed of the mag motor also, so i dont see where the fuss is coming from. RPM meters (not non-contacting) are 99.9% accurate so I for one would say rob measured it correctly.
JUst tried it on our old physics dept strobe and on a scale of 1-10 the disk is first stationary at 5. Its flashing very very quickly so I think its 50Hz, There arent any other markings on the strobe so I not sure what it means!
having just tested half of my batteries (yike! how many!!) i see where this has come from.
seems ive been doing all my calculations for years based on 66% of no load speed, which is fine on its own, but the batteries have basically cancelled the need to do this by having much higher voltage than stated. I did measure my batts a few years ago and knew they sat higher than stated voltage, but almost always dropped under load to near stated voltage. My newer stuff doesnt drop so low under load.
Appologies, seems Im wrong there Rob, but also right. If batts have the stated voltage, or drop to stated voltage, your measurement cant happen, but based on the 60 battery packs i tested last night, your measurement my well be bang on.
means any robot ive built in the last 2 years was 30% higher rpm than i thought.
inludes the ones coming out this year to then i guess. :)
Id put it down to cautious ratings on motors and batteries. When first tested (with a caled tacho) pimp 2 went well over 8600 rpm and went over 6k faster than the ideal world values we had should have allowed.
Just out of interest has anyone had their magnets move inside their astros, cos thats whats happened to mine. I think the motor is ok, it smells a bit but not to bad. Anyone got any advice as to the best method to glueing them back in, otherwise I will just do it as see what happens. Thanks,
Ed
Ed no idea about astros but I remember seeing an article on an american site about putting magnets back into a mag. I would imagine that the same process could be used on an astro.
Is this it Gary ?
http://www.madoverlord.com/Robots/MagMotorRepair.thttp://www.madoverlord.com/Robots/MagMotorRepair.t
We have had the odd magnet come loose, after trying a few types of adhesives we found Araldite 2014 (RS part no. 372-1748) is about as close as we have found to Astroflights original glue.
You need to carefully remove any old glue from both the magnet and motor body, make sure both surfaces are TOTALLY greese and dust free and once the magntet is in place leave well alone for at least 24 hours for the Araldite to cure.
Hope this helps.