Joined: 18 Jun 2004
Posts: 3842
Location: Queensland near Brisbane
Chain reduction
How would you decide what sized chain is needed for each stage of reduction? I am looking at using an
inrunner motor.
I want to replace a 100 w motor in a scooter. Might be a little powerful, but roboteer. I want to use 8s and at least 20:1 into a 190 mm wheel. The motor doesn't quote torque.
I haven't used chain reduction or brushless motors before so any advice would be appreciated. _________________ So even the rain that falls isn't actually going to fill our dams and our river systems
Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
You can probably use #25 chain for a scooter; its about the same size as bike chain and its really unlikely that the motor will generate more torque than you could. For that sort of money, I'd look at one of the Rotomax outrunners; they should have much more torque and most electric conversions seem to favour outrunners. _________________ Australian 2015 Featherweight champion
UK 2016 Gladiator champion
Mon Jul 07, 2014 10:19 pm
Glen Experienced Roboteer
Joined: 16 Jun 2004
Posts: 9481
Location: Where you least expect
Inrunner will probably be too fast for chains to deal with. 20:1 is a lot of reduction as well. Multiple stages for sure = complex + expensive.
The biggest outrunner with the lowest KV you can afford (rpm per volt) is what you want then you can get away with a single chain reduction. _________________ www.demon50s.com - Minimoto parts
http://www.youtube.com/user/HyzerGlen - Videoooozzz
Mon Jul 07, 2014 11:06 pm
Philip Experienced Roboteer
Joined: 18 Jun 2004
Posts: 3842
Location: Queensland near Brisbane
I did like the look of the bigger outrunners, such as
this one
. It would only require ~ 6:1. The Trackstar 200 A 8s would only give this motor just over half its maximum voltage.
This ESC
will supply the voltage and current, but I wonder if it will play happily as a land based ESC.
The
NTM 5060 380kv
would be a good fit for the larger Trackstar. I could get two motor and ESC combinations for the same price as the larger outrunner mentioned above. I have read where longboard riders use this motor as a power source, but they say they need to get it up to ~ 4 mph before the motor will work happily. The longboard riders where only using 6s at 3:1. More voltage and reduction would improve things.
I would like to use the motor in a customized go cart after testing it in the scooter. I am thinking of a differential drive three wheeler. The two driven wheels at the front and a castor at the back.
Would either of the above options be better than the other or is there a better option that I haven't considered? Thanks for your input. _________________ So even the rain that falls isn't actually going to fill our dams and our river systems
Tue Jul 08, 2014 3:23 am
Knightrous Site Admin
Joined: 15 Jun 2004
Posts: 8511
Location: NSW
It sounds like you need to read the teachings of Sir Charles "I'm on Hackaday weekly" Guan...
I honestly don't know of anyone else who plays with more brushless, gokart and EV related gear then Charles. His latest go kart, Chibi-Mikuvan runs a
Turnigy AquaStar T20 3T 730KV/1280KV Water Cooled Brushless Inrunner Motor
through a grinder gearbox and then a chain drive to the wheels. The controller is a Turnigy Trackstar 1/5th Scale Sensorless 200amp 8s Opto Car ESC.
For pure simplicity, I would consider a pair of
MY1018Z Unite 450W, 24V DC Brushed Gear Motor, 440 RPM
. You can bump these up to 36V and run further chain reduction to maintain the same output speed, but with better acceleration and torque. I've been looking at these as a replacement for the BotBitz middleweight drive train to replace the winch motors. _________________ https://www.halfdonethings.com/
Tue Jul 08, 2014 8:26 am
miles&Jules Experienced Roboteer
Joined: 19 May 2010
Posts: 3973
Location: ipswich QLD
I have given up on chains- they let me down every fight with judge mental-the planitary gearboxs i bought for the scooters would work well with brushless motors on the back i reckon- but if anyone can get chains to work its you phillip _________________ Miles Blow - Julie Pitts
www.mulesfilm.com.au www.wombokforest.com.au
-Pickasso- Vivid Sportsman champion 2015
Tue Jul 08, 2014 10:57 am
Daniel Experienced Roboteer
Joined: 30 Aug 2005
Posts: 2729
Location: Gold Coast
If the motor you end up selecting has a 8mm shaft you should use #35 chain. It is the same size chain that is used on go-karts and mini-bikes so it is easier to buy on ebay.
The #25/6mm chain that we have been using is too flexable. It really doesn't like being bumped around
Bike chain is #41 and it's almost impossible to find pinions to fit on motors in that size. #40 chain has the same pitch but is twice the width of bike chain.
I've used 6mm, #25, #35, #40 and #41 on different robots over the years and #35 and #40 have been the easiest to use and never derailed in combat. I just keep trying small chains because of weight and stupidity.
Tue Jul 08, 2014 1:24 pm
Philip Experienced Roboteer
Joined: 18 Jun 2004
Posts: 3842
Location: Queensland near Brisbane
quote:Originally posted by miles&Jules:
... the planitary gearboxs i bought for the scooters would work well with brushless motors on the back i reckon ...
Where did you get them?
Thanks for all of the advice. I probably would have bought the wrong stuff and had all sorts of problems. _________________ So even the rain that falls isn't actually going to fill our dams and our river systems
Wed Jul 09, 2014 6:26 pm
miles&Jules Experienced Roboteer
Joined: 19 May 2010
Posts: 3973
Location: ipswich QLD
quote:Originally posted by miles&Jules:
http://www.ebay.com/itm/Currie-Planetary-Gear-75mm-Planetary-Gear-for-Scooter-/281116107952?pt=LH_DefaultDomain_0&hash=item4173d364b0
They are only 4:1 ratio, so probably not enough for big wheels like Philip has advised. _________________ https://www.halfdonethings.com/
Wed Jul 09, 2014 9:42 pm
Nick Experienced Roboteer
Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
How about a Banebots P80 gearbox with a 16:1 reduction and then a 2:1 final chain reduction? Its a bit small for the job IMHO but there is nothing else around except at insane prices. _________________ Australian 2015 Featherweight champion
UK 2016 Gladiator champion
Wed Jul 09, 2014 9:50 pm
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