Worm Gears-worst efficiency

[motiondave]

Aldoz winches are a 300w motor, but they are sitting on a gearbox to provide pulling force. They are designed for moving 900kg slow.
Bobbuilt ran winches a while ago as well. Noisy, but very powerful.

And I asked the supplier of the motion dynamics motors about what sort of torque would be there near 500watts, he said according to the paper calculations, near 40nm of torque.
That would be probably quite near that as well for the ebay daytons.
Considering we are overdriving the motors something fierce.
But even he knows paper figures are not accurate.
A dyno meter device would solve all speculation, but unless you have one at your disposal, we can only assume that a big motor will provide enough power.

[motiondave]

motiondave hi.
experiment with a big motor. Turn the engine without load and check the number of PRM, it just repeats from the load.

ummmm......please explain why?

[motiondave]

Sorry Crack, I accidently deleted the post I just replied to.....sorry....

You said "motiondave hi.
experiment with a big motor. Turn the engine without load and check the number of PRM, it just repeats from the load."

[tronicgr]

If a supplier is honnest is allways a big question.
I regret to say ,but there isnt a international standard for motor/gearbox specs.
All compagnies make there own specs after there own rules.
(dyadic gives a 1G acceleration for there scn5,but he is missing steps doing that)see old forum.
Spurgears arent 98% efficient to,between 55% and 70% normaly it depents on there stages.
Planetary gears are the most efficient from the freewheeling gearboxes.
I am able to reduce costs with a JRK21v3 50usd and pmdc servo 60usd but need to pay 150 euro for a planetary gear.
I was thinking to make a ballscrew actuator for les,but Thanos scared me with the loadcell.
@Thanos:Do i realy need loadcel feedback,even when the forces from the sim are the 50% from actuator trust force.
sorry for my bad english.
regards

Ballscrew mechanism is another type of worm-gear but linear. I don't think you can backdrive a ball screw that easy under load. The little braking that the motor applies when its off (during to its winding shorted to the ground) should be enough to hold position for the gaps of the power pulses from the motor driver.

If you can fabricate cheap balscrew with low backlash, go for it!! Force-Dynamics for example is using ballscrew successfully in their 3DOF/4DOF systems for many years now! And they are so fast and smooth!!!

The loadcell is nothing to be scared of... It can be used along normal potentiometers or other positioning sensors, to help with the efficiency of the power side of the motor, for example to help overcome stall conditions. In general you can use loadcell to be able to deliver more or less power depending on the inertia of the mass, providing more smooth results and well spread torque across all possible positions of your actuators.


Thanos

[basthard]

guys we're almost there ....
we are finalizing the purchase of the various pieces and then race .....
according to our calculations should be sufficient to 500w
have a good rotation of screwball 25mm diameter 10 pitch ...
we talk about 200kg per actuator at a speed of outgoing 250mm / s
transmission with HTD 5 pitch sufficiently silent, with reduction (interchangeable) of 6:1 ...
as soon as new news ....
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basthard-thecure