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Admin (Admin)
Board Administrator
Username: Admin

Post Number: 413
Registered: 10-2004
Posted on Wednesday, February 28, 2007 - 7:10 pm:    Edit Post    Move Post (Moderator/Admin Only)

Hi Jeff,

Yes you can as it has a tank style mode (i.e. no mixing function). I'm confident that no properly run event will allow a heavyweight to run from a splat transmitter or are likely to accept 27MHz. With our 4-channel 40MHz FM sets starting at £34.95, you may find it false economy to use splat transmitters. I must point out the dangers of even testing a heavyweight at home with inappropriate transmitters. I'm quite happy to advise on general issues on heavyweight robots which remains of great personal interest. If you could register on the forum, it will make our life easier in replying.

Regards

Paul
roger styan (Roger)
Member
Username: Roger

Post Number: 1
Registered: 3-2007
Posted on Tuesday, March 6, 2007 - 11:33 am:    Edit Post    Move Post (Moderator/Admin Only)

Can you recommend a speed controller fo a 12v 2kW motor (Ex starter motor)? Please!
Admin (Admin)
Board Administrator
Username: Admin

Post Number: 424
Registered: 10-2004
Posted on Tuesday, March 6, 2007 - 7:59 pm:    Edit Post    Move Post (Moderator/Admin Only)

Roger,

Good question, we would not recommend using a series wound starter motor with any of our controllers. Please see http://www.4qd.co.uk/faq/bmnc3.html as 4QD offers a wealth of knowledge including this very topic. We are aware that some customers have used 4QD controllers with starter motors following motor modification but we still recommend against it. What is your application out of interest?
Don_jarr (Don_jarr)
Member
Username: Don_jarr

Post Number: 1
Registered: 3-2007
Posted on Tuesday, March 20, 2007 - 11:45 pm:    Edit Post    Move Post (Moderator/Admin Only)

Hi m8

A quick explanation, I am building a full size R6 unit, (Like R2-D2 but cone dome instead of round,) and it has two motors one in each foot, which will drive a custom made tank track assembly and I wanted it to steer like a tank.

I was looking at using a pair of your 12V 150W 6812S 1470-008, motors and just wondered if you done any sort of controller that worked like a tank sort of thing.

A guy on a tank forum said I would need a mixer, so steering and speed are automatically controlled together, but didn’t say where to get one.

I just wondered if you done anything like this. I did look through the various sections, but not really knowing what I am looking for didn’t help.

Many thanks

:-) Don
Admin (Admin)
Board Administrator
Username: Admin

Post Number: 438
Registered: 10-2004
Posted on Wednesday, March 21, 2007 - 9:35 pm:    Edit Post    Move Post (Moderator/Admin Only)

Don,

What is the weight of the R6? 150W sounds very under powered for a tracked bot even if only 3-4 mph.

I would prefer not to size a speed controller until the motor size is confirmed. We do mixers that allow single stick control (read our mixer post here ) for an explanation on mixers. The type of mixer will depend on the speed controller selected but check out our mixer range here

If you advise the weight and the speed, we should be able to help with sizing the motor.
Don_jarr (Don_jarr)
Member
Username: Don_jarr

Post Number: 2
Registered: 3-2007
Posted on Friday, March 23, 2007 - 12:51 pm:    Edit Post    Move Post (Moderator/Admin Only)

Hi m8

I am aiming on sub 40kg, as the bulk of its going to be carbon fibre with alloy for drive and moving parts. Speed needed is around 4mph. I am currently constructing a foot to see how much space will be available, but I was trying to get away with as small a motor as I can, to avoid having to pack it out with batteries as they are very heavy. It seems the average all alloy and steel R2 weighs in at 100kg + and most people use a pair of 100w or 140w electric scooter motors.

I did sort of base my motor size on an electric scooter the kid up the road owns which has a 300watt motor and can travel at 15mph carrying 100kgs. So I figured an R2 at less than half that weight and a third of the speed two, 150w motors would be ample.

However any info and advice is very much appriceated.

:-) Don
Simon Morrell (Morrells)
Member
Username: Morrells

Post Number: 1
Registered: 4-2007
Posted on Monday, April 16, 2007 - 1:08 pm:    Edit Post    Move Post (Moderator/Admin Only)

Hi
I wish to buy a motor controller which will allow me to drive 2 x 24V wheelchair motors and interface them to my RC receiver so that I just need to use one stick for speed and direction.

I know I'll need to unlock the solonoid brake. I was just going to connect the joystick that came with the wheelchair but I can't think of a way of moving the stick in the X and Y axis using servos - hence the reason for me looking to use a separate motor controller.

Can you recommend a motor controller that will do the job?

Best regards
Simon Morrell
Admin (Admin)
Board Administrator
Username: Admin

Post Number: 454
Registered: 10-2004
Posted on Monday, April 16, 2007 - 6:58 pm:    Edit Post    Move Post (Moderator/Admin Only)

Simon,

You didn't mention the motor size but let's assume 10A FLC. I assume you require radio control of the motor speed.

You could use a pair of 4QD Vortex 35A controllers (1511-021) with a 4QD interface 3401-005. There is another option using our H bridge controllers but without knowing more about your application, the 4QD solution is a safer bet.

Regards

Paul
Neil Holdstock (Mrgadget)
Member
Username: Mrgadget

Post Number: 1
Registered: 5-2007
Posted on Sunday, May 13, 2007 - 10:21 pm:    Edit Post    Move Post (Moderator/Admin Only)

I am building a truck (model of peterbuilt 379) it will be about 1.2m long and have 10 off 250mm wheels (overall hieght inc tyres). over 3 axles. I need to work out how best to steer it, would it be best to use 1 or 2 servos or one of your geared motors and a h bridge speedo, How would i get the wheels to return to centre. I am going to set it up with radio control. It will have a max wieght of 155kg's laden. I would think approx 30kg's over front axle.
Admin (Admin)
Board Administrator
Username: Admin

Post Number: 487
Registered: 10-2004
Posted on Monday, May 14, 2007 - 12:54 pm:    Edit Post    Move Post (Moderator/Admin Only)

Neil,

This sounds like one monster of a truck! I would be surprised if any of our standard servos would be able to turn a pair of 250mm wheels with 30kg on them. You would really need to know how much torque your steering mechanism needs to move with the vehicle stationary and on max grip surface. Servos are quited typically with kg/cm torque figure. A motor with controller is much more likely to be up to it and probably work out cheaper than going for an industrial servo. You would need an H Bridge controller with feedback. That way you would have a pot connected to your steering rack and this signal would be compared to the joystick signal from the receiver. This way the steering will always follow the joystick signal.

In order to recommend the right parts, can you give some idea of the torque figure needed. It doesn't have to be precise as we can build in some contingency into the motor. Just one other bit of info needed, how quickly to you want to be able to go from lock to lock.
Neil Holdstock (Mrgadget)
Member
Username: Mrgadget

Post Number: 2
Registered: 5-2007
Posted on Monday, May 14, 2007 - 4:43 pm:    Edit Post    Move Post (Moderator/Admin Only)

I am not sure exactly what the torque would be as have not got that far as yet but does 25 to 30 kg's sound close, maybe on grass it could rise beyond anything expected. I do think the motor driven idea is best, so that is the way i will go. could this be done with the front wheels being joined with a type of threaded bar, then a bracket in the centre with a drive nut on, a sprocket welded to the nut then the sprocket driven from the motor, or would this not self centre. (just a basic idea) also looking at the speed in which the steering goes lock to lock, I do not really expect it to go as fast as a small car as this would require to much power, and add more weight to an already heavy machine. I guess if it took 2 or 3 seconds lock to lock I could live with that, it would be more in keeping with the size anyway.
Admin (Admin)
Board Administrator
Username: Admin

Post Number: 488
Registered: 10-2004
Posted on Monday, May 14, 2007 - 8:39 pm:    Edit Post    Move Post (Moderator/Admin Only)

Neil,

Whilst 20 -30kg on the front axle may be a good estimate, the torque figure remains important though and that is a figure you should come up with unless you want to follow the trial and error method. As for methods of steering, that is beyond our scope of support although another reader may be able to help. The electronics will take care of the self centering. 2-3 seconds for lock to lock sounds sensible.

I would suggest looking at what other builders use for steering mechanisms, there are even a few combat robots that use this method of steering. Look up Ackerman steering on the net as this would be a good method to choose in my opinion.

I would suggest building the steering mechanism and then estimate the torque needed by doing a few simple experiments. We certainly will have a suitable motor and electronics, it's just what size to offer.
Neil Holdstock (Mrgadget)
Member
Username: Mrgadget

Post Number: 3
Registered: 5-2007
Posted on Monday, May 14, 2007 - 10:30 pm:    Edit Post    Move Post (Moderator/Admin Only)

Thanks for the info, have been looking on internet at the ackerman steering. didn't realise there was so much to steering geometry, still that has solved that. there are also sites that recommend the use of geared motors for steering rather than servos. so that is obviously the way to go... I will now look into the method of operating the steering and get back to you on the motor torque needed. Many thanks for your help..
marc winter (Wildshot)
Member
Username: Wildshot

Post Number: 1
Registered: 6-2007
Posted on Tuesday, June 12, 2007 - 8:10 pm:    Edit Post    Move Post (Moderator/Admin Only)

I wish to build an off-road vehicle to carry one person and a payload ( combined weight 100kg) and a vehicle weight of about 60 kg (including batteries.
I was intending to use 2 of your 24V 350W MY1016B4M6 motors with chain drive to the wheels. What I am not sure of is which controller to use, I want to drive both motors as one and be able to reverse. Please could you recommend a controller solution.
I also have a 24 volt 350 watt mobility scooter for which I need a controller, this must offer reversing also, any suggestion will be much appreciated.
Admin (Admin)
Board Administrator
Username: Admin

Post Number: 502
Registered: 10-2004
Posted on Tuesday, June 12, 2007 - 9:44 pm:    Edit Post    Move Post (Moderator/Admin Only)

Marc,

No problem in putting both motors electrically in parallel with VTX 24V 75A driving them.

For a single motor, you would get away with a VTX 24V 35A. Both of these solutions will require a pot type throttle input with a reverse switch / ignition.

Feel free to ask if you need any further assistance.
wullie (Wullie71)
Member
Username: Wullie71

Post Number: 1
Registered: 6-2007
Posted on Friday, June 15, 2007 - 3:12 pm:    Edit Post    Move Post (Moderator/Admin Only)

Hi
Looking to convert an Electric outboard.
Looking for a speed controller with control via a variable resistor.
The motor is 12v and runs approx 40A. ~(38Ib Thrust.)
The control at the moment is via two switches.
One does direction the other is speed.
5 speeds.
Admin (Admin)
Board Administrator
Username: Admin

Post Number: 505
Registered: 10-2004
Posted on Friday, June 15, 2007 - 5:21 pm:    Edit Post    Move Post (Moderator/Admin Only)

Wullie,

The 4QD VTX 75 12V 1511-023 will be fine. Use a 10k pot for the speed and a toggle switch for the reverse. You can also add an ignition switch and it is even possible to combine the reverse and ignition into a single switch. The pot will give a smooth speed control from stop to maximum with on-board presets to set the max speed, the acceleration & deceleration ramps.
Scott
Unregistered guest
Posted on Friday, July 13, 2007 - 11:19 am:    Edit Post    Move Post (Moderator/Admin Only)

I'm looking for a speed controller and potentiometer to control a pair of Fracmo 24v, 5 amp ex-wheelchair motors for use in a Toylander vehicle I've built for my son.
Looking through your products it looks like the 4QD Pro 120 Series is probably the one, but your wiring diagram only shows one motor connected, how would you wire in a second motor (1 motor to each of the rear wheels).
Knowing very little about electrics would it be possible to supply a wiring diagram when I purchase a speed controller from you, if I were to let you know what was going in the vehicle.
Admin (Admin)
Board Administrator
Username: Admin

Post Number: 522
Registered: 10-2004
Posted on Tuesday, July 17, 2007 - 7:35 pm:    Edit Post    Move Post (Moderator/Admin Only)

Scott,

The PRO 120 is far too large for the small motors you specified. With a total working load of just 10A, the VTX 24V 35A will be fine. As for a potentiometer, use a 5 or 10k linear pot for which we offer two types, the more expensive one offering better performance.

The speed controllers come with full instrcutions and there is no problem in wiring both motors in parallel.

You did not leave an Email address so we could not send you a personal reply.
Alan Brassey
Unregistered guest
Posted on Friday, August 17, 2007 - 9:57 am:    Edit Post    Move Post (Moderator/Admin Only)

I am building a 2 x Class 20 - 24 volt battery powered Locomotive. Each will be driven by 4 DC motors and I am considering purchasing the Technobots Feather Gold 24V 150W - Part No: 1410-010. Can you supply a speed controller for each loco that will operate the 4 motors and can the 2 loco's be operated by one switch for forward and reverse plus horns and lights. The 2 loco's will either be driven as a pair or as a single unit.
Admin (Admin)
Board Administrator
Username: Admin

Post Number: 559
Registered: 10-2004
Posted on Sunday, August 19, 2007 - 9:29 am:    Edit Post    Move Post (Moderator/Admin Only)

Alan,

The 4QD VTX 24V 75A 1511-024 -034 boxed version) will be a good choice for each loco.

To use each loco as a single unit means each will require its own ignition / direction switch and throttle and battery supply. To use them as a pair is possible with a little ingenuity with the switching. You will need to common the 24V supplies on the negative side to do this (common ground). When ordering, include a note with a request to supply a drawing of how to connect up the controllers in this way.