High torque / Low speed motor recommendations for the following idea?

[12axe]

yes I realise Im going to have to test this and make some mistakes as theory part isnt easy for brain to take onboard due to my issues , I was just curious any way to save some heartache later or worse disasters .

The other thing that just hit me too was the degree of rotation , I mean if its the full 360 even with 10 turns that is a lot of twisting on my hands , so while I could handle 180 or 230 - 40 ok it would get uncomfortable if im having to turn it a lot over a period of time, so is it standard to have twist all the way round to reach 5 volts or are there ways using something like microcontroller to alter that too i.e. so i only have to turn 180 deg to reach 5v as opposed to 360 or whatever ?

thanks

snok

[12axe]

Its not so much the turn rather than the interval or length of turn between each 5% that the problem because it means I will have to flex my wrist round a lot more ( i.e. 20 turns within 180 no problem , but even 5 over 360 a real pain )

I did look at digikey but theirs only starts at 220 , and even choosing that theres still only 2 I can see at 10k - neither at 5 but 10%- there are none at all for 180 ,so I dont where those mobility folk get them, unless they make them themselves. ?

snok

[12axe]

Can you tell me what the power rating i.e. 2 watts meant to represent on digikey site?

the pots itself only takes 1amp x 5 volts = 5 watts

snok

[12axe]

It says each input on the 5v terminals on the sabertooth can take up to 1 amp ( sorry my mistake ) so Im assuming the safety input is something like 2 or 2.5 watts with 5 being the max ?

snok

[12axe]

can you give an example of what you mean by standard, do you mean a 5 turn , 5% 10k so youd have something like this ?

(0% twist) -> 0 Ohms
(25% twist) -> 2.5k Ohms
(50% twist) -> 5k Ohms
(75% twist) -> 7.5k Ohms
(100% twist) -> 10k Ohms

thanks

snok

[12axe]

I notice your out of CIM motors for now, so I had look around and noticed this site selling gearboxes for Cim too.

Would something like 12:75:1 you think be too much of a reduction for my uses , or would you recommend something lower ?

thanks again,

snok

[12axe]

So am i correct in assuming all I would need is the CIM motor itself , or do I need the sprockets too , and the encoder to convert the signal ?

thanks again,

snok

[12axe]

What do you think about having dual motor setup within the same gearbox like this , as opposed to having one on both wheels ?

Are there any drawbacks or would it allow me more torque at lower speeds ?

m

[12axe]

Just how powerful a controller ( $$$$$ )roughly are we talking ?

I saw this video this video of what loads this thing can handle , and was pretty surprised .

thanks,

snok

[12axe]

Ok the gear set up between the cluster cogs are the same for the the 14:1 ( 14:88:1 ) but cog on the motor itself smaller ( 12 teeth for 14:1 as opposed to 14 for 12:1 )

Does that also mean I could use the other ratios like 12.5:1 I take it as well. ( curious )

snok

[12axe]

What about this controlleryour sell ?

thanks,

snok

[12axe]

The AX3100S should be able to handle two CIM motors:

• 30s: 120A
• 1min: 100A
• 3 min: 80A
• 1h: 80A

The CIM consumes 20-25A, so two of them would consume 50A, which is less than 80A (which that controller can sustain for 1 hour). When climbing a slope, the current can increase to 100A, and that’s fine so long as it’s not for too long. There’s a lot of built-in protection, so it’s a good choice.

How exactly does the overruning clutch work with most of these motors ?

If I want to disengage the motor from the driven shaft can I do it via the controller at certain speeds i.e. for say if I was to go down a hill to cause the wheel to spin faster than the set speed

Or do I need to buy / machine some sort of discs onto the shaft that will allow me to do it without having to switch the power off all the time or keeping turning the pot ?

snok

[12axe]

Do you think it would be possible to use one of those 14 tooth gears used for AM gearboxes on a freewheel that was much larger like this ? ( curious )

snok

[12axe]

I was planning to use it with chain , I got told id need a #25 chain so I assuming this 65 Tooth Rear Sprocket should work ok then.

snok

[12axe]

That was the idea , but Im bit concerned after reading this ( 4th post down )

Would that also apply to the CIM too ( given its sensorless ) if I added a freewheel ?

Or does the Pot take care of that problem ?

snok

[12axe]

Sorry I am getting mixed up again , Its actually a 10 tooth sprocket I was advised to use with #25 chain / freewheel
see here.

thanks,

snok

[12axe]

It seems ok from what i see.

I think Im going to go for a 50 degree 10K pot so I can use finger throttle it seems the best solution for my weak hands as the reg pot is to fiddly and the twist even worse to hold.

It would be nice to have the reg pot too for longer distances so I could focus on steering without having to hold a lever to keep speed.

Am I correct in assuming the following means I could use the rotary pot at a set speed / resistance while using the the finger throttle for acceleration / DE-acceleration within those parameters i.e +20% so on, so that finger throttle is restricted to whatever the resistance is ?

So in other words using the 2 two pot together allows me a lot more range at lower resistance than otherwise possible with just a rotary pot because it allows you increase between each % until the % on the tachometer and Potentiometer level out .

**
Special Function Inputs/Outputs

2 Analog inputs. Used as
Tachometer input for closed loop speed
control
Potentiometer input for position (servo mode )
**
snok

[12axe]

Yes i think I got the tachometer confused as another speed input when all it does is measure it ( like a speedometer )

Im guessing those mobility scooters with those controls must be using some unique controller that allows for 2 Potentiometer inputs then , as they have a finger throttle and pot on nearly all of them .

I was trying to find out by looking at some and noticed it mention 2 types of speed control and noticed it mention 2 types of speed control : 5k pot from the looks of things and 25k micro speed ??

see here

what is micro speed ???

Does this have something to do with micro speed controllers likeshown here for RC motors ?

snok

[12axe]

Could I use a diode or something to override the speed pot so I was using the throttle ( options 1 & 2 ) ?

As I see it these are my options for controls ( option 1 & 3 being my ideal choice )

( option 1 ) - No hand gripping req

The pot was the speed control and no Throttle was used

**
( option 2 ) - Vice versa**
**

( option 3 ) - Hand gripping needed**

The pot was the limiter and the Throttle was the speed control

**
( option 4 ) - Vice versa**

snok

[12axe]

http://media.joomeo.com/large/5041192ac90e9.jpg

what about something like this ?

where you piggy back another non centering throttle pot across the existing sprung loaded one, and stop then switch over between pots for option 1.

I assume the rotary pot would need to be centered while doing this for controller i.e. so it was in neutral , and then all you need the SPDT switch to swap between the pot wipers.

snok