Calculating Speed for a Mechanical Dolly Driven by Electric Motors

In summary, the conversation was about using electrical winch motors to power a mechanical dolly with 18" wheels. The question was how to calculate the speed of the dolly and determine the size of the sprockets needed. The solution was to calculate the RPM of the winch drum and the wheel, which ended up being the same, resulting in the need for sprockets of the same size. A drawing was suggested for further clarification.
  • #1
fanning21
2
0
Hi there,

I have recently been working on a project that involves building a mechanical dolly that is driven by 2 electrical motors.

I have decided to use 2 electrical winch motors which each have a rating of 5700kg and a drum size of diameter 64mm

My question is, how do I calculate the speed of the vehicle if I am planning on using 18" wheels.

Do i need to calculate the rotational speed of the drum first?

I need this information in order to decide which sized sprockets I am to use.

Thanks!
 
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  • #2
Using the rating and the drum diameter you can find out how much torque it will produce (you'd only need this to confirm that the motors are strong enough to power your dolly for a certain vehicle weight and/or certain incline). You'll have to find out what the rpm of the drum is either via the description or by testing it out. You know the wheel size and you'll have to decide what vehicle speed you want so you can pick out the sprocket based on that. Or if there is a maximum sprocket size that you can put in your design or that you wouldn't want to exceed you can choose than to find the vehicle speed. I'm a little confused about how exactly the motors will be driving the motorized dolly. Are you going to attach sprockets to the wheel shaft and the motor shaft? Or are you going to attempt to make the wench cable go around a pulley to turn the wheels? Or something else? Maybe a simple drawing would help.
 
  • #3
If you have the horsepower/kW you can calculate the speed.
 
  • #4
Thank you for the quick response, and sorry if my explanation was not too clear!

My plan was to attach one sprocket to the winch drum and another one to the shaft in order to drive the wheel..

My issue was deciding on the ratio of the sizes of the two different sprockets. I first calculated the RPM of the drum using the diamater and line speed. Then I calculated the RPM of a 19" wheel with a speed of 3 km/h

Basically both RPM's are roughly 33rpm which means that both sprockets must be the same size!

Does this make any sense??
 
  • #5
fanning21 said:
Thank you for the quick response, and sorry if my explanation was not too clear!

My plan was to attach one sprocket to the winch drum and another one to the shaft in order to drive the wheel..

My issue was deciding on the ratio of the sizes of the two different sprockets. I first calculated the RPM of the drum using the diamater and line speed. Then I calculated the RPM of a 19" wheel with a speed of 3 km/h

Basically both RPM's are roughly 33rpm which means that both sprockets must be the same size!

Does this make any sense??

Yup, that makes sense. The sprockets would be the same size since the rpms wanted for the wheel shaft and what the winch produce are the same. Good luck with your project.
 

1. How do you calculate the speed of a mechanical dolly driven by electric motors?

The speed of a mechanical dolly driven by electric motors can be calculated by dividing the distance traveled by the amount of time it took to travel that distance. This is known as the formula for speed, which is speed = distance/time.

2. What factors affect the speed of a mechanical dolly?

There are several factors that can affect the speed of a mechanical dolly. These include the type and power of the electric motor, the weight and load of the dolly, the terrain and surface it is traveling on, and any external forces such as wind resistance.

3. How can the speed of a mechanical dolly be increased?

The speed of a mechanical dolly can be increased by using a more powerful electric motor, reducing the weight and load on the dolly, or optimizing the terrain and surface it travels on. Regular maintenance and lubrication of the dolly's moving parts can also help to improve its speed.

4. Is there a maximum speed for a mechanical dolly driven by electric motors?

Yes, there is a maximum speed for a mechanical dolly driven by electric motors. This is determined by the capabilities of the electric motor and the design of the dolly. It is important to follow the recommended speed limits for safety and to avoid damaging the dolly or its components.

5. How accurate are speed calculations for a mechanical dolly driven by electric motors?

The accuracy of speed calculations for a mechanical dolly driven by electric motors depends on the precision of the measurements taken for distance and time. It is also important to take into account any external factors that may affect the speed, such as inclines or rough terrain. Regular calibration and maintenance of the dolly and its components can help to ensure accurate speed calculations.

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