Gearbox Ques.

[fseboi]

I have a .75kW elec. motor with a gear box on it with a reduction ratio of 100:1 and torque is 317

The intention of this is to lift AND HOLD a sound and lighting truss aprrox 6mtrs in the air, weighing about 1500kg.

I want to know is there ANY way of finding out what the elec. motor and gearbox hold in the air, in kilograms...

Thanks,

Get back to me on snowy424@hotmail.com

Thanks

 

[ScottyUK]

Buy a purpose-made electric hoist. It will cost less overall by the time your homebrewed item has been certified for lifting applications. You were going to get it certified, weren't you? The safety aspects, and potential liability arising from any failure of a lifting device, is bad enough using commercially available products, let alone home-made ones.


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One day my ship will come in.
But with my luck, I'll be at the airport!

 

[Barry1961]

The gear motor combination you have will not work as it is. The pitch radius of the drum/sheave/sprocket would be too small. You would need an additional secondary reduction.

Calculating the amount of weight that the gear motor can lift involves a lot of information besides the straight math of torque to linear force.

Are the bearings in the gearbox rated to handle the overhung load?
What is the minimum bend radius of the cable you are using?
What is the size of the drum?
What is the efficiency of the gearbox?
Does the gearbox have a high starting friction, worm gear?
Does the motor have a spring set brake?
Is there a load brake?
What type of motor, AC, DC, servo?
How fast does this need to lift?
Will the platform be guided?
What is the co-efficient of friction of the guides?
If there is a jam how much force will be produced?
What is the weak link in a jam?

The torque rating of the gearbox is probably 317 Nm (Newton-meter). If you had a 2 meter diameter drum the radius would be 1 meter and in theory you could lift 317 Newtons. If the radius was 0.5 meter in theory you could lift 634 Newtons. But in reality it is not that simple at all.

.75 kw is enough power to kill several people at once. 1500 kg suspended 6 meters in the air is enough power to kill the rest. Even if you buy a hoist get some familiar with structural steel to mount it. This is nothing to guess at unless you don’t mind killing the people nearby.

Barry1961