Torque converter on a board?

Torque converters seem pretty awesome: efficient n quiet. Why aren’t any boards using one?

Because the purpose of a torque converter is to solve an issue that electric motors don’t have. Same reason electric cars don’t use torque converters.


Maybe I should say fluid gearbox. I know a torque converter can disconnect when the vehicle stops moving which wouldn’t be a help but a coupling w a 3:1 that was liquid would be cool and quiet.

A torque converter’s main function is to remove the need for a clutch between a prime mover and a transmission/gearbox, to allow the prime mover to idle while in gear.

Since electric motors don’t need to idle, and thus don’t need a clutch, they don’t need a torque converter.

They’re inefficient, messy, large and a pain to design.

Gears/belts are cheaper, cleaner, more efficient and easier to design.


I am not totally sure If you and @MysticalDork is thinking the same. If you are, just ignore this:

As far as I know the torque converters job is to make the engine stay in its optimum rpm range, as they put out more torque at higher rpms vs lower.

However Electric motors dont have this problem as they put out the same torque all over the rpm range, which makes the torque converter unessecary

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This reminds me of putting a differential on an esk8. Cars have differentials because they don’t have two engines. One engine per wheel would be far better and allow maximum power transfer. They get over this limitation by using a differential so the car doesn’t have torque steer as a single-wheel drive. The other alternative is to reduce the number of rear wheels like the Polaris Slingshot.

To reduce the number of motors, just to create the problem, so you can solve it by using a differential – sounds silly to me.

This topic reminds me of that.

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Maybe @Hummie want to use it for his hubmotor in some kind of creative way?

i think he wants to try to use a 100kv motor with a 3:1 coupling. that would result in excelent start ups and will overcome the speed limit of a (100kv*battery voltage*wheel diameter) motor by 3.

Then he could use planetary gears - or anything else besides a torque converter? Electric motors already have full torque all the way down to zero speed …

This is like adding a clutch when you could just stop applying power to the motor

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2018 prediction: someone releases a “torque converter” that’s not a torque converter, just like someone else released direct drive that’s not direct drive


a fluid gearbox is what Im looking for. Isnt there a 3:1 fluid gearbox? a coupling maybe or something. don’t know the terminology. @DeathCookies no application in mind, more so a regular pulley board. If could make a quiet fluid gearbox be pretty cool

A torque converter only works when you have a speed diferencial between the impeller and the turbine, it wouldn’t convert torque across all the rpm range, the lower the ratio the less multiplication, so when your wheel is stopped and you engage the motor you have maximum multiplication, right as you start to move this drop really fast

And even so the multiplication of most cars is between 1.2 to 1.3, not a lot

For eboard I think the efficiency loss would be to big to make sense, unless we complicate the design and include locking up at higher rpms, most cars do that to improve fuel economy

ok maybe a torque converter isn’t what I was thinking. isn’t there some type of liquid gearing mechanism?

Yep, basically every hydraulic motor is a fluid gearing, a motor that pressurizes a fluid and that fluid is used to do work, take a look at hydraulic pumps and hydraulic motors

I’ll be searching not that I want to do it, butcan it do a speed to torque conversion like a pulley and 3:1?