| Author |
Message |
Francis Thompson (Francis40s)
Member
Username: Francis40s
Post Number: 4
Registered: 1-2009
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| Posted on Saturday, January 24, 2009 - 11:19 am: |
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Hey, I'm building a big(ish) UGV, and am using 4 1.1kW starter motors, each of which pull 91A. I'm looking for speed controls capable of running two of these motors each, and they have to be suitable for use with a standard radio control receiver. I've seen RC boat ESCs which claim a limit of over 400A (http://www.ripmax.com/item.asp?itemid=P-XTRA-SESPRINT&selectedtab=060&Category=0 60-050-120), but it seems impossible, especially when you consider that the motor wire only has cross-sectional area 2.5mm^2. What do you think? |
Admin (Admin)
Board Administrator
Username: Admin
Post Number: 963
Registered: 10-2004
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| Posted on Monday, January 26, 2009 - 7:01 pm: |
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Francis, I can't think of a motor much worse than a starter motor for your application as they frequently take 40A before they even start rotating. Your choice though but we would urge you to reconsider your motor choice. We would not recommend any of our motor speed controllers for use with a starter motor especially if it is series wound.
Don't get me started on these claims from many motor speed controller manufacturers. they tend to claim the absolute maximum rating of the MOSFET transistors rather than the controller as a whole assembly. I have tested that particular controller and without water cooling it was good for about 20A continuous.
Sizing a speed controller is not just about the max current rating but is also about motor inductances and back emf's. Large bodied low current motors are rather good at popping controllers designed for small high current drain motors. |
Quadra (Quadra)
Member
Username: Quadra
Post Number: 6
Registered: 1-2008
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| Posted on Tuesday, January 20, 2009 - 9:04 pm: |
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Hi Paul
I don't know if you remember me, but I asked your advice about a speed controller for a childrens small scale landrover which is running two 24v 370w motors. You advised me that a VTX 75 would be a good choice and that tacho feedback system would work really well, as I wanted to restrict the top speed mechanically via the throttle pedal. Anyway, when you enquired with 4QD they said that they would only sell you 5 TFB's and not just one, and that was where we left it. I got onto 4QD (god help me!) and asked if they would supply the speed controller with one TFB, and they said they would. This pleased me as I had already attached the generator motor to my main motor, but I would have prefered to have bought the hardware from you, to say thanks for the technical help. I have completed the build and the system you suggested works brilliantly, I reckon its got enough torque to pull my wifes fiesta.
This is a shot of it in action, fully loaded.
www.youtube.com/watch?v=sY_jeMKkjvg
So thanks for all your help with the electrical side of things, I did purchase some others bits from you and I have passed your name onto other builders and they all love the shop.
Cheers Mike |
Admin (Admin)
Board Administrator
Username: Admin
Post Number: 964
Registered: 10-2004
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| Posted on Monday, January 26, 2009 - 7:11 pm: |
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Mike,
Yes I remember your application from about a year ago, also I remember being disappointed that 4QD would not support their distributor in getting you the model you needed. I glad to hear you got it sorted and the video of the land rover looks great. Thank you for your kind words and recommendations to other builders.
Regards
Paul |
Max Hunter
Unregistered guest
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| Posted on Tuesday, January 20, 2009 - 10:18 pm: |
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We're building a Greenpower electric racing car (to be powered by a nominal 240W DC Fracmo motor) - we were looking for a speed controller which would be able to power this, preferably from the 4QD range. It should be capable of regenerative braking - what would you reccommend? We were looking at the Pro 120 and the Pro 150 but couldn't see many differences (apart from one being programmable) - and what of the 4QD 4QD series? Please advise... Thanks, Max |
Admin (Admin)
Board Administrator
Username: Admin
Post Number: 965
Registered: 10-2004
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| Posted on Monday, January 26, 2009 - 7:20 pm: |
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Max,
Assuming the motor is 24Vdc, I would suggest using the smallest of the 4QD range the Vortex-40 24V 1511-021 unboxed or the 1511-031 boxed. As your motor is only going to be drawing say 12A or so, a 40A controller is plenty big enough. It does have regen breaking as well. |
space_ma
Unregistered guest
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| Posted on Sunday, February 15, 2009 - 7:37 pm: |
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can you suggest a good speed controller which will work for a featherweight robot that will also work with the RE 385 Planetary Gearbox 100:1 moter |
Admin (Admin)
Board Administrator
Username: Admin
Post Number: 981
Registered: 10-2004
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| Posted on Tuesday, February 17, 2009 - 8:17 pm: |
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Hi,
The RE385 100:1 geared motor draws under 1A so just about any of our speed controllers from Dimension Engineering and Electronize and others will be fine. I can't imagine what you would be using such a small motor as this in a featherweight robot for though. |
David Barnsley
Unregistered guest
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| Posted on Tuesday, March 24, 2009 - 10:24 am: |
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Hi,
I plan to use two of your 24v 150w gold motors using your sabertooth dual 25A speed controller to control my featherweight robot.
I will be powering it from 3 x 7.2v 3300mah batteries connected in series
could you tell me if this combo will work together ok. if not could you recommend a dual controller that will work.
Regards, Dave |
Admin (Admin)
Board Administrator
Username: Admin
Post Number: 1018
Registered: 10-2004
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| Posted on Wednesday, March 25, 2009 - 7:02 pm: |
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Dave,
I am quite happy with that setup, the motors stall at 25A which is within the controller rating plus you are running at a reduced voltage so the currents will be even lower. |
David Brandon
Unregistered guest
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| Posted on Sunday, April 12, 2009 - 5:44 pm: |
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Hi I am looking to use two bosch 750w motors in a skid steer format. please could you tell me what I would need to controll these. I allready have a transmitter and reciever and would like to control the digitaly.
Regards
Dave |
Admin (Admin)
Board Administrator
Username: Admin
Post Number: 1035
Registered: 10-2004
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| Posted on Monday, April 20, 2009 - 9:39 pm: |
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Dave,
Not sure that I completely understand your question as regards controlling digitally. The receiver outputs a pulse of between 1 and 2ms depending on the transmitter joystick position. Normal practice is to take this signal into a motor speed controller(s). If you can explain your digital control requirements, we should be able to explain a suitable setup. |
Deevee (Deevee)
Member
Username: Deevee
Post Number: 2
Registered: 4-2009
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| Posted on Tuesday, April 14, 2009 - 11:56 am: |
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Hello again! Another question for you - bit more general this time. I have some small fans; 12v DC (like the sort you find inside computers) and I want to be able to control their speed over an R/C link. Which speed controller is best suited to this job - or a better question maybe- how do you go about specifying an R/C speed controller against a motor? I'm planning on having a few of these fans wired up in parallel. Any tips would be much appreciated.
Cheers
Dev |
Admin (Admin)
Board Administrator
Username: Admin
Post Number: 1036
Registered: 10-2004
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| Posted on Monday, April 20, 2009 - 9:50 pm: |
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Dev,
Specifying a motor speed controller is based on such parameters as motor current, need to reverse, motor body size (motor inductance), interface method, response time, how aggressively it is used (combat robots speed controllers are not only subject to mechanical shock but also rapid motor reversals often full forwards to full reverse in under 200mS).
Your application is very simple, cooling fans tend to only draw a relatively small current and will not really stress a controller. I would suggest the Dimension Engineering controller Syren 10 our part number 1506-001. |
Mark
Unregistered guest
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| Posted on Wednesday, April 22, 2009 - 9:27 pm: |
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Hi there new to this.
I have been wanting to create my own Go Kart, I have therefore been looking up the possible options. They are now talking about using DC motors on a fast moving fast accerelation kart? Is this true? can a motor possibly have that much power and acceralation and what would i controll it with which motor driver? Would i need a geared motor or a direct drive? Can a battery possibly even hold enough energy for long enough? or would you have to have a series of batterys? I have been reading the web page and still can not really understand what is needed for basic motor movement for this IE: do i need any more than motor, motor speed controller, foot pedal throttle, battery, wires?
Thankyou
Julian
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Admin (Admin)
Board Administrator
Username: Admin
Post Number: 1042
Registered: 10-2004
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| Posted on Sunday, April 26, 2009 - 8:40 pm: |
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Julian,
"They are now talking about using DC motors on..." Who are they? Yes you can build an electric powered go kart but you have not given indicated what sort of performance you are after. I just built an electric kart for my son which quite happily goes around the garden at about 8mph. If you want a Kart to compete with IC engines then that is very different but possible but will have limitations.
You will need a motor speed controller but until the motor is selected, the controller cannot be specified yet. By asking the question of whether you need a geared motor or direct drive suggests you need to do more research. Check out our robot speed calculator and you will find that a 3,600 rpm motor on direct drive with 11" wheels will do over 112mph although it is highly unlikely to get there before burning out the motor.
Battery life depends on battery technology, motor power, efficiency etc..
Your last sentence sounds about right in what you need, switches and safety links would also be needed. |
Bill Cubbin
Unregistered guest
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| Posted on Saturday, May 2, 2009 - 12:57 pm: |
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Hi,
I have an electric tricycle with an EMD PM50/63-NE-24-GB4 25/1 gear ratio motor. (http://www.emd.co.uk/range/pm50+gb0.php)
I am looking for a speed controller that will give variable speed with regenerative braking. Would you also advise on the additional factor of reversing. Many Thanks.
Bill Cubbin |
Admin (Admin)
Board Administrator
Username: Admin
Post Number: 1052
Registered: 10-2004
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| Posted on Saturday, May 2, 2009 - 7:18 pm: |
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Bill,
Is that 24Vdc version?
I have a concern over regen braking, are you sure that you can regen with a worm drive gearbox because as far as I know you cannot. |
Bill Cubbin
Unregistered guest
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| Posted on Sunday, May 3, 2009 - 12:31 am: |
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Hi Paul,
Thanks for getting back to me so promptly. It is the 24v DC motor and you are correct regarding the regen braking as the trike is not fixed gear. Silly me.
Bill Cubbin |
Admin (Admin)
Board Administrator
Username: Admin
Post Number: 1053
Registered: 10-2004
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| Posted on Wednesday, May 6, 2009 - 8:46 pm: |
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Bill,
As the motor appears to be just a couple hundred watts, if we assume say 12A running current and that you do not require reverse, I would suggest the 4QD uni series 24V 40A part number 1514-424. A chassis plate and cover is also available should you need them. |
