Archive through January 7, 2008
| Author | Message | ||
| Admin (Admin) Board Administrator Username: Admin Post Number: 530 Registered: 10-2004 |
Robin, Hopefully you spot this reply as you did not leave a reply Email address. Yes we will almost certainly have a suitable motor. Torque is a function of both wheel size and motor power and gearbox ratio. At the moment, too many variable exist to recommend a motor, if you can decide on a wheel size, 'vehicle' speed and are there any motor physical size constraints? From this we should be able to recommend a product. |
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| robin Unregistered guest |
Thank you for your reply! I have no physical size constraints for the motors or the wheels. I imagined the wheel size to be about 6cm diameter but it doesn't really matter. I just need to make best use of the 4300mAh battery while travelling 50 meters yet also need to make slow, small (2cm) movements. Therefore I need the wheels to respond to a range of voltages (up to 6v), but with still enough torque to move at the low voltage speeds. I was hoping the cheapest of the Tamiya geared motor boxes would do? (I have a tiny budget, sorry!). It's 1 motor per wheel by the way. |
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| Admin (Admin) Board Administrator Username: Admin Post Number: 533 Registered: 10-2004 |
Robin, If you could quote the maximum desired speed in mph or m/s that would really help in choosing the right product. Also, what running time are you looking for from the battery? |
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| Robin CW (Robin) Member Username: Robin Post Number: 1 Registered: 7-2007 |
I could start with specs and get a quote, but I should start by saying I can't spend more than 30quid on motors and wheels. A speed that is comfortable to walk at would be good, maybe between 30 to 50m/s |
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| Jamie McHarg (Ayrshirerobotics) Member Username: Ayrshirerobotics Post Number: 9 Registered: 4-2006 |
I don't know any humans that could walk 30 metres or 50 metres in a second and say they did it comfortably!  Comfortable walking speeds are usually around 1.5m/s to 3m/s. Sounds fun otherwise, a laptop on wheels |
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| Admin (Admin) Board Administrator Username: Admin Post Number: 537 Registered: 10-2004 |
Robin, As Jamie points out, a good walking speed is about 4mph or 1.8 m/s. If you need feed the 60mm wheel diameter, 4mph & a 1:1 gear ratio into our robot speed calculator which you can find on the top nav bar of the shop, you get 569 rpm. I would recommend the 1450-052 motor which would give you about 6 mph at 7.2V. You could also consider the 1450-102 which gives 4.8 mph at 7.2V but at a lower power. Unfortunately the Tamiya range does not quote final RPM so it is a bit of a gamble. The 1452-011 has 6 possible ratios so one of these may well suit as may the 1452-007. Both of these will work with the Tamiya sports or narrow tyre set. |
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| Robin CW (Robin) Member Username: Robin Post Number: 2 Registered: 7-2007 |
Ha ha I'm sorry, I meant 30-50cm/s ! A slow walk. Thanks for the advice. I wonder what the acceleration would be for those models? |
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| Admin (Admin) Board Administrator Username: Admin Post Number: 539 Registered: 10-2004 |
Robin 30-50cm/s is rather slow, much slower than walking pace. If this is the speed you want, you may well get away with a higher reduction geared motor and a lower power rating. This is why it is important to get the basics such as wheel size and speed early on. Hopefully you have enough info to select your motor. |
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| Terence B J Perks Unregistered guest |
Hi, I am developing a prototype rotary display unit for a Client. Have found your website which appears to have all the components i need to construct this. Unit will be free standing self contained, ie no trailing wires, with a rotating weight of app 12kg,to rotate at say 5 rpm, on an 8 hour continuous cycle with overnight recharge. I require a geared motor unit (950D?, battery pack,charging unit and speed reg(?) Can you please quote me for a compatible package including costs and availability. Your reply keenly awaited. Regards Terence B J Perks |
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| Admin (Admin) Board Administrator Username: Admin Post Number: 545 Registered: 10-2004 |
Terence, Unfortunately you did not leave an Email address to send you a quote. All prices can be found on our website but in terms of part selection: Motor 1450-106 should be okay but with the long running time, 1450-056 could be a better bet. You will need to check on the running current to size the battery but a 12V 7.2Ah would be a good start. A suitable charger would be the 1070-031 and a speed regulator would be the 1062-004 or 005 (panel mount version). Carriage costs depend on where in the UK you are but for the above it would most likely be £8.75 due to the weight of the battery. |
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| Kjs_kabin (Kjs_kabin) Member Username: Kjs_kabin Post Number: 1 Registered: 10-2007 |
hello, I am looking for a motor to power a childs car.This is a mini hotrod and the motor needs to be able to comfortably move the weight of a child upto age 6. I need the motor to be able to go forward and reverse. Would the power axle on your site be powerful enough? what would you suggest? thanks simon |
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| Admin (Admin) Board Administrator Username: Admin Post Number: 604 Registered: 10-2004 |
Simon, You did not supply an Email address so hopefully you spot this. All of our motors will go forwards and reverse but you would need some form of motor speed controller. If you are referring to the MY9716, this is way way over powered for your needs, even the MY7712NZ (1471-103) is over powered but would be usable. Speed depends on wheel diameter but under 200mm should be about right, you can slow if down further with a speed controller. |
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| mikemoden01 Unregistered guest |
I am building a replica childs Bugatti car for my small grandson and wish to have it electrically driven. Any advice on motor, drive system and battery would be much appreciated and I can then place orders. Many thanks, Mike |
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| Admin (Admin) Board Administrator Username: Admin Post Number: 610 Registered: 10-2004 |
Mike, We will have a suitable motor in our range but we will need further information to make a recommendation. Can you advise us the wheel diameter, desired speed and the estimated vehicle weight. Additional information such as running time and any limitations on size or space would help as well. |
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| Darrenkarp (Darrenkarp) Member Username: Darrenkarp Post Number: 1 Registered: 11-2007 |
Hi, I'm about to embark on making my own flight simulator motion platform and need to ascertain if you have the correct specification 24vdc motors available. I'm not that technical when it comes to motors with gearboxes so have pasted a section from the plans below: Drive Power - minimum 240W - actual choice 280W Drive Force - 657Newtons - actual choice 741N Drive output speed - ideally around 16rpm - actual choice 11.4 rpm This uses a motor arm of approx 15cms in length to obtain the torque required. Can you help? |
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| Admin (Admin) Board Administrator Username: Admin Post Number: 627 Registered: 10-2004 |
Darren, You did not leave an Email address so we are unable to send you a personal reply. Our geared motors are intended for drive motors on electric vehicles so their final RPM is far higher than you are seeking. You could use further speed reduction using our gears or chain sprockets but that depends on your application. For example, our motor 1471-109 which is 250W has a torque of 6.25Nm at 380 RPM with a further 24:1 reduction would give a torque output ignoring losses of only 150Nm. This is only a quarter of what you are looking for unless your quoted torque relates to the torque at a distance of 15cms. In which case our motor with the 24:1 would give 1000 newtons at 15cm. So no, we do not have such a heavily geared motor of that power but with additional reduction, yes that's is possible if our understanding of your figures is correct. |
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| Darren Karp (Darrenkarp) Member Username: Darrenkarp Post Number: 4 Registered: 11-2007 |
Hi, It appears I haven't given you enough information about the torque values. Here is an excerpt from my platform design manual: We need to find a motor/gearbox combination with as high a torque as we can, which also has the right power and output speed. The one we have selected has 280W power and output torque of 100Nm and output speed of 11.4rpm (geared down from a motor speed of 4000rpm). This is, as with all things, a bit of a compromise. We would like a higher output speed (possibly around 16rpm) but that would mean a reduction in torque (down to 62Nm). Bringing back the definition of torque (force applied at a set lever length, like a long handled spanner), we see that we have a 100Nm drive needing to resist 657 N. That then sets the length of the motor arms for us. The way torque works is that the shorter the lever, the more force you have to apply (like trying to remove your car wheel nuts with a small wrench). So, if our drive has a torque of 100Nm it will exert a force of 100Newtons on the end of a 1 metre lever - or 1000Newtons on the end of a 0.1metre lever (100mm). We need a force of 657Newtons to resist the downwards force of the payload, so our lever length should be: - 100Nm x 1000mm/657N = 152mm As you will see, we have again allowed for some safety factor here and will use a lever length some 10% shorter i.e. 135mm. In summary, we have worked out the following parts of the motion base: - Drive Power - minimum 240W - actual choice 280W Drive Force - 657Newtons - actual choice 741N Drive output speed - ideally around 16rpm - actual choice 11.4 rpm Can you help at all? Regards Darren [email protected] |
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| Admin (Admin) Board Administrator Username: Admin Post Number: 635 Registered: 10-2004 |
Hi Darren, Looks like our assumption was correct regarding the torque figures. Regardless, we do not stock any high power geared motors with such a low output speed. The best we can offer is one of our geared motors with a further reduction using sprockets or gears but that is a lot more work for you. So sorry, we cannot help with a direct drive geared motor. Regards Paul |
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| Richard Minter Unregistered guest |
Hello Paul, I wonder if you can help. Im in the process of building a hog roast. Can you advise me of a suitable motor that could cope with rotating a spit mounted pig of up to 60Kgs in weight at about 3 revs per minute. regards, Richard Minter. |
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| Admin (Admin) Board Administrator Username: Admin Post Number: 656 Registered: 10-2004 |
Richard, A couple of points come to mind on this application. We could assume an evenly balanced load but that would not be the case. So an assumption, an in balance of 20kg at a distance of 30cm gives a torque excluding losses of 6kg/m. Our small 21W 3000:1 geared motors are rated at only 4.6 kg/m. An additional concern would be any additional load caused by the cook prodding at or cutting of the hog whilst it was turning. Whilst we have motors that would have sufficient power, they do not have a low enough final speed for you without further reduction using gears or sprockets. I'm not sure we can help with this application although a current limiting supply could help protect our small motors. Regards Paul |
