Large motors to move over 40kg!
  • Calling all motor experts!
    I'm looking to find some DC Brushless motors that can power a large payload of up to 20-40kgs! I'm aware that I won't be able to pull the power required to feed the motors directly from the AlexMos card but that doesn't matter as I can use a separate umbilical cord to power this.
    What I'm after is to try and find a larger unit but still be able to control this from the software. Does anyone have any good ideas?
    Many Thanks in advance
  • Direct driven bisycle motor, maybe rewounded, maybe as it is.
  • les moteurs utilisés chez elektor pour leur copie du segway, du coup, il y a aussi les schémas du bloc puissance et de plus, avec centrale inertielle
  • Thanks everyone for their responses, much appreciated! Even this biggest motor will probably be to small ariellago! Do you think I could use some more powerful pancake motors with gear reduction for this! I'm not to sure how the motors are controlled by the software. I have a few cards coming for testing purposes but without buying every motor under the sun for testing I wondered if someone could steer me in the right area. Hopefully the end result will be of use to everyone and there's something very special that's it's being used for! Thanks again!
  • Rogz, my french is a bit bad.. but I think I understand what your saying... I check out those motors and have a look!
  • 2 GB85 on tilt will be enough power! to move 40kg
  • Hey AOPEN3434, Thanks for that. A good find.. I put an order in for a couple to play around with... do you think you could power these from the standard 32bit board or will I have to look at other power options?
  • yes you can power from the 32 bit controller 3s to 6S battery
  • I'd use dual GB90's on tilt: http://www.rvrd.com/product/tiger-gb90/
    Dual GB90 on roll (can be done with modification
    Single GB90 w/ 5:1 reduction on Pan
  • The GB90 is very powerful, I am using it with 4S for RED gimbal, but I think it could take easily higher voltage if even more power is needed.

    40Kg though, I would try bisycle motor (something like this http://www.ebay.com/itm/Brushless-Mini-Hub-Motor-48V-250W-for-Front-Wheel-2013-Newest-for-Electric-Bike-/181043544288?pt=Other_Vehicle_Parts&hash=item2a270940e0&vxp=mtr)

    Motor Type: Brushless Gearless Mini Hub Motor
    Max. Torque: 15N.M !
  • Hey Thanks itsaok and Garug, I didn't realise there was a GB90 on the way.... I've just order 5 GB85's...Doh... maybe I can get them swapped out before they ship!
    Can I ask why I would need the 5:1 reduction on the Pan? I thought that the board itself would sort this movement out.. or are you just referring to making the motor work with less stress because of the weight?

    Many Thanks
  • 5:1 would give you 5x the torque using the same motor than direct drive.
  • Normally, on direct driven motor, the motor does not need to accelerate as it is just trying to keep everything on place as they where. On reduction geared motor, the motor needs to accelerate and stop.

    How well does this work in practise? the upside is more torque, the downside lower correction speed and I guess kind of latency because the motor accelerating and stoping, but those of you actually using reduction gear, does it work well?

    Also, just out of interest, how is the 40 kg camera operated, is it installed on a boat, helicopter...
  • Thanks Garug & itsaok!

    My 5 GB85'S arrived and I'm just placing them into our steel mockup rig for mounting and sizing templates. I'm going to see how the motors cope with the weight of the camera and lens direct. We're using a Red Epic which although doesn't weigh that much the ultraprime lenses do! Plus when you've got all the 3 lens motors on board you start to wack up the weight.

    To answer your question about where we're using it... well I can't tell you exactly but it's for a big project and it's being mounted on a specially designed camera car. We start doing test at the end of this month so I'll be sharing all the details with everyone so you can see how we're getting along!

    Many thanks for everyone's help so far.. I'm sure I'll have more questions popping up soon!
  • Interesting and challenging. Stabilisation, vibration dampening, controlling.

    Especially moving a big and really heavy camera with joystick might be challenging and hard for the motors. (accelerating and stoping the mass). Stabilisation requires really strong and steady mechanics and good balancing.
  • Ok so did our first motor test on the heavyweight gimble last night... Does anyone know the maximum amount of power the GB85's can take?
    We don't have to worry about running them off a battery as we're going to use a umbilical cord to the device.
    I know the Alex mos card can take between 10-25 volts.. We were feeding it a filtered 12v supply last night but even at 255 power on the board it felt that the motors could take some more power.
    Can't find a spec sheet for these motors or the pin outs anywhere on the net and helpfully didn't come with the motors!

    Again if anyone could shed some light it would be much appreciated. Also had a lot of jitters and constant rotation of the motors.. but I think that's a setup thing and will get to that in good time!

    Many Thanks
  • I am running the GB85 at 4S i.e. 15-16 volts and it gets a bit warm at 200.

    Just monitor the motors during the testing that the do not get hot.

    Note that if you are using more than 1 motor per axis, they need to be synchronised

    Pinout of the motors? The 3 pins are equal, you do not need to worry about that. Only if the motor is spinning wrong direction, swap any 2 pins or use invert on GUI.
  • Thanks Garug,

    I'll try stepping up the power supply and see how I get on... I've been told they can take up to 22v so 15-16 sounds good!

    What's the best was of synchronising the motors.. is this something that can be done once and then they stay in sync?
    We're going to use 2 on tilt and 2 on roll, they'll be fixed together with an axel so I guess it's best to match these up well at the start.

    Will start uploading some pictures of the project next week!

    Many Thanks
  • Synchronising is one time mechanical adjustment. You need to be able to rotate one of the motors about 360/42 degrees, so that you can get the phases to match.
  • Hey Garug, You don't happen to know what the rpm of the GB85 are do you?
  • I have no exact information on that but as all gimbal motors they are very low KV motors. I would not use it for anything else than gimbal and for direct driven gimbal it is fast enough.

    I am not sure about the gimbal controllers, but with ESCs the rpm depends of voltage.

    My guess would be in range 40 to 80 KV, i.e. in range 600 - 1200 rpm with 15 V. But it is just a guess.
  • Hey Garug, that's great thanks for the reply. We're only using the motors for the gimbal head.. just looking at putting some reduction gear in for the pan motor and wanted to work out the reduction.

    We've been doing some tests and we've found that the wind resistance is quite strong on the frame as we move faster and I don't think we've got enough torque on the motor so I wanted to step it up.

    If that's not enough I may have to look into using some kind of segway type of motor but have no idea how I would interface with the card!

    Many Thanks
  • the gb90 is much stronger than gb85, but probably not strong enough for setup you are describing,

    probably an electric bike or segway type motor would be good. the important thing is that the resistance is high enough, 10 to 20 ohms, otherwise it could load the board too much.
  • I guess the board wouldn't be able to supply the power for this.. would you have to use some kind of amplifier for the signal? Do you know anyone who had done this... or is their anyone here that has done this?
    I'm going to have a go with the reduction gear and see the results whilst looking for some new motors!
  • As long as the resistance is high enough I think it would be fine. I have not measured a electric bike motor, probably it would be too low resistance and amplifier would be needed, but it could also be winded to be high resistance.

    My current system with GB85 motors uses only 1.5 A total from 15 V, that is 22,5 W and less than 8 W per motor.

    This board can handle 6S (25V) and 3A per motor http://flyduino.net/Alex-Mos-Brushless-Gimbal-BLG-32bit-Basecam_1 So it could provide around 75W per motor. That should be enough power, but would require correct resistance on the motor winding. R=U/I= 25/3= 8.3 ohms, I would go for 10 to 12 ohms not to overload the board. (but this calculation should be verified before starting to build any motor ;-)
  • As always Garug... you are the legend! I'll upload some photos soon so you can see what we're up to in Film land!
  • Hey... Its been a while so I thought I would write an update... So I've got the camera frame assembled now and have completed the anti-vibration head that goes on top... as you can see its a beast!

    We've hard installed the motors into the arms and can line them up with mechanical adjustment.
    I'm just hoping that they are going to be powerful enough?

    We've got 2 for Pan on reduction gear , 2 for Tilt direct drive and 1 for roll on a reduction gear.

    The camera car is finished with all the mountings so we're just going to go into the testing stage now! I feel i'm going to run in to troubles with the wind loading!

    What I was just wondering... if these are not powerful enough, I'm going to have to step up to a 24V DC motor with Rotary Encoders on the back and Harmonic drives on the front.

    Now does anybody know... or can anybody modify the Basecam software to run these motors and do the stabilization?

    Would be willing to pay if someone can do this? .... Anyone!




  • Looks huge you should use encoders. Probably not powerful enough without encoders. I can help.
  • Hey Garug, Thanks for the message, yes I may need to add encoders... can I ask how much more power it gives the motor? I've got the GB85's and they are 6kg/cm, I think i need to get that up a bit to deal with the wind alone!
  • Yes, that will not be enough, with encoders GB85 can provide much more torque, but I think still not enough. GB90 with encoders at 24 V could maybe take 10+ load, but I think 40 kg would be too much even for that.
  • I had a weight check with the camera and lenses on the front so i'm about 8-9 kgs with the battery and the lens all up. But then i need to add the remote focus and zoom control so i need to allow minimum of 10kgs! I guess I am going to need bigger better motors!
    Had a look at your rig Garug though... how did you get on with the wind loading... did it knock the controls out at any point?
  • I am not sure what rig you mean, the RED one?

    I am currently using the GB90 and GB85 motors with encoders, and with encoders it does not really get knocked out. But there might be vibrations etc due wind loadings. What kind of speeds are you thinking of?

    10, even 15 kg is much different than 40 kg. 40 kg is really huge and dangerous weight. Dangerous because the inertia, and 40 kg would require much different construction than 15 kg.

    Many years ago I was tuning this kind of tree axis tables http://www.ideal-aerosmith.com/motion/three-axis-position-and-rate-table-2103htc/ It was able to take 100 kg load, but even without load it was scary to see that thing moving 60 RPM , though it was placed in metal cage that had to be locked for it to start.

    Also 15 kg is dangerous if rotating some + 180 degrees/s as these gimbals can. It could easily crush a hand. That is especially important to remember when setting the system up and would be good idea to tune it first time with a mockup of the camera/lens system, not to break the real thing if the gimbal gets out of control.

    That was enough of safety.

    15 kg could be doable for GB90 sized motor with encoders. Not sure though.

    What kind of movement is needed?

    1. How much does the gimbal need to turn up/down, does it need to roll other than stabilise when attached in car, does the yaw need to rotate full 360? It would be good to minimise the gimbal size and if movement can be somewhat limited, that helps. Maybe also having axis order Pitch, Yaw, Roll would help if up and down movement can be limited to some +-40 degrees.

    2. How fast moving with joystick is needed. That requires really huge force from the motors to start and stop 15 kg if fast speeds are needed.

    Ps. How much could the camera/lens weight be reduced, battery probably could be placed outside the gimbal, would be good to look also to the lens and accessories, if weight on those can be reduced. The price of the gimbal goes exponentially up when the camera system gets more weight... 9 kg would be much nicer than 15 kg. It would be also good to get rid of all loose mass, that is not firmly attached mass, they cause easily reduced performance on gimbals.

  • Hi Garug, could you pls confirm me that GB90 counts 42 poles? ...As seems impossible to find this detail on the net...thx!
  • Yes, GB90 is 42 poles.
  • Hello everyone, I began to be testing larger motors and have one that is CDK Direct Driver. This motor comes with the controller and has a torque of 5 Nm, and is a lot of power, ideal for my projects. But connect this with the most powerful engine controller Pro W-BGC and fails to move at full power. Its potency is equal to an engine GB95.

    There are some solution like put an amplifier?
    It would be great to use this power, but the W-BGC PRO driver fails to yield to this engine to the fullest.

    Any ideas?
  • That is interesting looking motor, but what motor exactly is it. Is it 3 phase direct driven brushless motor? What kind of resistance it has per phase? How many poles?

    It could be that it has very low resistance, and that would cause problems.
  • there are also tiger GB90, i-flight GB100 & i-flight GB110 motors if you need more power
  • This brushless motor and has 3 phases. It works perfect with the BGC driver.
    I leave a link to the detail:

    Page 22

    Also I have the original driver of this engine, it's worth ...

    Previously I did a test with the original driver, and the engine has plenty of power:

    Obviously he is working with more tension, a 60volt per phase.
  • Working in the film industry over 15 years ago. I am with this project over five years ago, even before he left the gimbals drivers. This motor is very expensive, about U$D1000 approx. If one could avail maximum power with BGC controllers can be used in gimbals for heavier cameras.
    Not just for the cameras, but for the great effort you have to make a large head.

    As you can see in the video, the original driver of this engine is much bigger, working with 220v and has more technology.
    There is something very wise in this, you can not compare one with another controller, although the W-BGC PRO controller is small, has its power, but not enough.

    That is why I happened to think if there is a 3-phase amplifier for this engine, thus we would be a good solution.
    Or consider using the original motor controller.

    What do you think?
  • I did not find the technical data, how many poles, what resistance per phase.

    Could you measure the resistance?

    If it is between 2 and 10 ohms, the BaseCamBGC Pro should be able to drive it with good power.

    The motor looks like it has a build in encoder. not very likely it works directly with BaseCamBGC Pro board, but could be, depending of the sensor type. It would be possible to install a separate encoder, but a bit difficult.

    For best power encoder should be connected.

    The motor looks very good construction, probably can take big load with its bearings no problem and no additional support needed.

    If the motor is between 2 to 10 ohms, I would suggest you contact BaseCam via email provided here.

  • It has 3 phases as any brushless motor gimbal. Each phase is 29 ohms. It is a little high.
  • if I had to make the biggest and most powerful engine that you can use with the controller SBGC as could be and how hard would it have?
  • Well, I would resume this conversation.
    Anyone know how we can reach the maximum power of the big motors?

    There will be a new electronics Basecam, powerful enough for large motors, or be a PWM amplifier?

    Anyone have any idea?
  • It depends of motor, My biggest motor weight 2 kg alone, it is now 10 ohms. normal board (1.5 A drivers) can handle it at 15 V and it gives nice tongue.

    BaseCam Pro board can handle 8A, 25V so that could handle pretty powerful motor.