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Chain reduction


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Philip
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Joined: 18 Jun 2004
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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.
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Post Mon Jul 07, 2014 7:51 pm 
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Valen
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Don't use chains ;->

</trollface>
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Post Mon Jul 07, 2014 8:39 pm 
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Nick
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Joined: 16 Jun 2004
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Location: Sydney, NSW


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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.
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Post Mon Jul 07, 2014 10:19 pm 
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Glen
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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 Smile then you can get away with a single chain reduction.
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Post Mon Jul 07, 2014 11:06 pm 
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Philip
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Location: Queensland near Brisbane


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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.
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Post Tue Jul 08, 2014 3:23 am 
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Knightrous
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It sounds like you need to read the teachings of Sir Charles "I'm on Hackaday weekly" Guan...

http://www.etotheipiplusone.net/?p=3278

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.
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Post Tue Jul 08, 2014 8:26 am 
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miles&Jules
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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 Very Happy
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Post Tue Jul 08, 2014 10:57 am 
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Daniel
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Joined: 30 Aug 2005
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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.

Post Tue Jul 08, 2014 1:24 pm 
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Philip
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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.
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Post Wed Jul 09, 2014 6:26 pm 
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miles&Jules
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http://www.ebay.com/itm/Currie-Planetary-Gear-75mm-Planetary-Gear-for-Scooter-/281116107952?pt=LH_DefaultDomain_0&hash=item4173d364b0


here is one on ebay USA Very Happy
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Post Wed Jul 09, 2014 7:47 pm 
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Knightrous
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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.
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Post Wed Jul 09, 2014 9:42 pm 
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Nick
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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.
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Post Wed Jul 09, 2014 9:50 pm 
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