Burf2000 Posted October 6, 2011 Posted October 6, 2011 Hey there, I been meaning to ask this for a while. So, I read you should not really run more than 2 XL motors off a PF rechargeable battery, however how many should you run off a train controller / Dacta control Lab? What about if you had xl motors running off a nxt? Should you not run more than 2 at a time. I am trying to think of ways to power my robot better and it uses a lot of xl motors Quote
DLuders Posted October 6, 2011 Posted October 6, 2011 From the Power Functions Frequently-Asked Questions (FAQ) webpage, it says: "2. How many Power Functions Motors can I drive from one Power Functions Battery Box? "As a rule of thumb, you can drive 2 Power Functions XL-Motors, 3 Power Functions Train Motors or 4 Power Functions M-Motors at the same time from one Power Functions Battery Box. If you wish to run a combination of motors, you can e.g. have 1 XL and 2 M running together. The XL-Motor requires about twice as much power as the M-Motor. The Battery Boxes and the IR Receiver have overload protection, so attempting to drive too many motors will not damage anything. The power a motor consumes depends on what function the motor is performing. Motors will operate best when driving a small load." So, it is the Power Functions (PF) Receiver that is limiting the current output. If you don't use a receiver (and connect the motors directly to the PF Battery Box), you can run more than two PF XL motors but you run the risk of damaging them from overcurrent overheating. Most of the Lego Battery Boxes can produce up to 9V. If you want to run additional motors, you'll need additional battery boxes but their additional weight will strain the robot's motors more. It's a vicious cycle. If you use the 8878"]8878[/url] Power Functions Rechargeable Battery Box (pictured below), it's light weight (but lower output voltage of 7.4V) may be worth the high cost. Quote
Burf2000 Posted October 6, 2011 Author Posted October 6, 2011 From the Power Functions Frequently-Asked Questions (FAQ) webpage, it says: "2. How many Power Functions Motors can I drive from one Power Functions Battery Box? "As a rule of thumb, you can drive 2 Power Functions XL-Motors, 3 Power Functions Train Motors or 4 Power Functions M-Motors at the same time from one Power Functions Battery Box. If you wish to run a combination of motors, you can e.g. have 1 XL and 2 M running together. The XL-Motor requires about twice as much power as the M-Motor. The Battery Boxes and the IR Receiver have overload protection, so attempting to drive too many motors will not damage anything. The power a motor consumes depends on what function the motor is performing. Motors will operate best when driving a small load." So, it is the Power Functions (PF) Receiver that is limiting the current output. If you don't use a receiver (and connect the motors directly to the PF Battery Box), you can run more than two PF XL motors but you run the risk of damaging them from overcurrent overheating. Most of the Lego Battery Boxes can produce up to 9V. If you want to run additional motors, you'll need additional battery boxes but their additional weight will strain the robot's motors more. It's a vicious cycle. If you use the 8878"]8878[/url] Power Functions Rechargeable Battery Box (pictured below), it's light weight (but lower output voltage of 7.4V) may be worth the high cost. They are what I use at the moment and are very light weight, I was wonder how many motors you can run off a train controller? Quote
DLuders Posted October 6, 2011 Posted October 6, 2011 I was wondering how many motors you can run off a train controller? The 4548 "Transformer and Speed Regulator" produces a 9V output. That set consists of the 2868b "Electric, Train Speed Regulator 9V" and an electrical transformer to match your country (all seen on this Bricklink webpage). To run Power Functions (PF) motors, you will need a 58118 "Electric, Power Functions Extension Wire with one Light Bluish Gray End (length 50cm)" -- one end clips onto the Train Speed Regulator and the other end clips onto the PF motor. Quote
Burf2000 Posted October 6, 2011 Author Posted October 6, 2011 Hey, I have all that, my question is how many xl motors do we think it can run at once? Quote
Tadej Posted October 6, 2011 Posted October 6, 2011 (edited) So, it is the Power Functions (PF) Receiver that is limiting the current output. If you don't use a receiver (and connect the motors directly to the PF Battery Box), you can run more than two PF XL motors but you run the risk of damaging them from overcurrent overheating. That is not true, have you ever opened a PF battery box, it has a circuit breaker that limits the output current to 800mA. So if you try to connect more than two XL motors directly to the battery box it will not provide enough current to power the motors. As a solution to this problem you can bridge the circuit breaker with a piece of wire, that is what I did when my bulldozer was going slow due to the lack of power and after that it ran like new. Edited October 6, 2011 by Tadej Quote
Jundis Posted October 11, 2019 Posted October 11, 2019 Instead of opening up a new thread for the questions, I just use this one instead: Has anybody tried to power a small pneumatic pump with the wedo M-motor? Also, is it possible to use the same motor with maybe a little gearbox for controlling a pneumatic switch? As I don't already have either the motor nor the switch, it's hard to guess. At least in the Arocs, an L-Motor was used for the pump, but maybe the M-Motor will do the job...? I like to operate two big cylinders with it, speed (air pressure) is not that important. Quote
allanp Posted October 11, 2019 Posted October 11, 2019 (edited) I don't have a wedo motor but if it's similar to the PF M-motor then it should be fine. I know you said speed wasn't important, but if you do find it to be a bit lacking from the wedo motor you can always add a second pump 180 degrees offset from the first pump. As for using the same motor to control the switch you might want to look for "pneumatic autovalve", such as the one posted by Sariel below: Edited October 11, 2019 by allanp Quote
Jundis Posted October 11, 2019 Posted October 11, 2019 2 hours ago, allanp said: I don't have a wedo motor but if it's similar to the PF M-motor then it should be fine. I know you said speed wasn't important, but if you do find it to be a bit lacking from the wedo motor you can always add a second pump 180 degrees offset from the first pump. As for using the same motor to control the switch you might want to look for "pneumatic autovalve", such as the one posted by Sariel below: OMG, this is genious...! Thanks a lot! Quote
Techniccrack Posted October 12, 2019 Posted October 12, 2019 On my project (the Turbo Spider), i use 4 XL motors the same time. But on heavy load the batterybox was the limiting factor here. The protection kicks in when overcurrent (4 motors draw 1600 mah on load). Batterybox is able to power around 850. So i used 2 batteryboxes, two motors per receiver / box. its fine. The 9 regulator can only provide 300 mah. With minimum load no problem, but 4 XL motors way to much. my project made 3 spins and boom, the protection kicked in. hope this helps a little Quote
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