Power Functions - combining different motor types

[xXFoxhound90]

Hi everyone,

Two little question regarding Power Functions:

1. Is it possible to combine 2 L-motors with 2 XL-motors at the same time, working on the same gear of a car (2,0-2,5 kg) or will only motors of one type work? 

2. How many M-, L- and XL-motors can be used on a single 8887 rechargable battery box (to move the same car as above) at the same time?

Thank you in advance! 

xXFoxhound90 

[Aventador2004]

combining 2 types of motors wont work to drive because they rotate at different speeds. 

l motor: fastest.

m motor: only a bit slower.

XL motor: slowest, lots of torque.

i personally think XL is best but that is my opinion.

[aminnich]

Are you looking to have 2 different motors with one output shaft?

 

[Buddy010702]

  On 4/22/2017 at 2:14 PM, xXFoxhound90 said:

1. Is it possible to combine 2 L-motors with 2 XL-motors at the same time, working on the same gear of a car (2,0-2,5 kg) or will only motors of one type work? 

2. How many M-, L- and XL-motors can be used on a single 8887 rechargable battery box (to move the same car as above) at the same time?

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1. It is possible, but I don't suggest it. It's called a adder, and you will need a differential to connect them. Search for a Adder, or if you have sariel's book, you can look there. I don't suggest it because it loses a lot of torque, and is usually large, but nonetheless, it is possible.

2. I don't know exactly how many, but I think it's something around 2L motors, or 4XL/M motors. Don't quote me though. It's a small amount that you can have though.

[Aventador2004]

i forgot about using a adder, they are fast but low torque.

a adder is one side of diff is direct drive the other is connected through another gearset

 

Edited April 22, 2017 by Aventador2004

[xXFoxhound90]

  On 4/22/2017 at 2:31 PM, aminnich said:

Are you looking to have 2 different motors with one output shaft?

 

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Yes, only one output shaft.

I've seen in a video, that 4 L-motors were used to motorize the 42056 Porsche. But I don't really know, if they are all connected to a single battery box:

Alright, so I will only use one type of motor. Sariel's book seems to be a really good information source. Thank you! 

Edited April 22, 2017 by xXFoxhound90

[Aventador2004]

ok, problem solved.

[DugaldIC]

Read through this amazing build by Brunojj1, he's combined an XL with and L motor direct driven with the L motor geared down 3-1. This is the only time I've seen two different motors used at once. 

[mocbuild101]

  On 4/22/2017 at 2:14 PM, xXFoxhound90 said:

1. Is it possible to combine 2 L-motors with 2 XL-motors at the same time, working on the same gear of a car (2,0-2,5 kg) or will only motors of one type work? 

2. How many M-, L- and XL-motors can be used on a single 8887 rechargable battery box (to move the same car as above) at the same time?

Expand  

1. yes but only through an adder, it would be easier (to hard couple them) if it was 4 L-motors OR 4 XL-motors

2. I think 6-8 M-motors, 4-6 L-motors, or 2-4 XL-motors. But it depends on how much they are loaded.

[xXFoxhound90]

Ok. Thank you both of you! Brunojj1's solution looks interesting. I've also ordered Sariel's book to read more about adders. 

[BusterHaus]

I used an adder in one of my early builds. It used two L motors but would work with any combination of motors. 

 

[Void_S]

  On 4/23/2017 at 4:47 PM, BusterHaus said:

I used an adder in one of my early builds. It used two L motors but would work with any combination of motors. 

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It's a very unusual assembly... I'd suppose that initially it was two L motors with no adder and with servo right behind the front axle 

[Blakbird]

Yes, it works just fine.  You don't need an adder, although that is one option.  You can drive to the same output without an adder but you will want to adjust the gear ratios so that the motor speed is about the same or the slower motors will end up dragging on the faster motors.

[xXFoxhound90]

  On 4/24/2017 at 6:54 PM, Blakbird said:

Yes, it works just fine.  You don't need an adder, although that is one option.  You can drive to the same output without an adder but you will want to adjust the gear ratios so that the motor speed is about the same or the slower motors will end up dragging on the faster motors.

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Yes, adjusting the gear ratios was also my first idea, when I was thinking about using different motors. Thank you for advice!

[shadow_elenter]

If you just take a differential, connect the 2 input motors to that on both sides, opposite to each other so the output axle is one in contact wit the differential housing ring...
Where would you lose the torque? obviously the gear ratio difference between the diff housing ring and the gear you put against that, but that's easily solved by gering it back the other way.
Where would the "real" loss occur? 

Gr Onno

[Aventador2004]

  On 4/25/2017 at 11:07 PM, shadow_elenter said:

If you just take a differential, connect the 2 input motors to that on both sides, opposite to each other so the output axle is one in contact wit the differential housing ring...
Where would you lose the torque? obviously the gear ratio difference between the diff housing ring and the gear you put against that, but that's easily solved by gering it back the other way.
Where would the "real" loss occur? 

Gr Onno

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In the friction of the 5 gears + extra for diff. The housing also twists and allows years to slip.