Dear friends:

I would like to know the method of calculation for starting torque for hoist applications. I mean how to determine starting torque for given hoist load.

Thanks
Sri

Simple machanics and calculations that you should know. I suggest that if you dont already know how to calculate torque requirements for load applications that trying one for a crane is not a good idea.
My suggestion is that you shouldn't do it and rather get an experienced engineer involved. You are dealing with safety issues and can't be relied upon if you don't know how to calculate. You can cause some serious damage or injury. Rather safe ...safety comes first...Get an experienced person involved.

In case you are planning to install a VSD on your hoist,I suggest you refer to jraef post on the selection of vsd for hoist application. You will find many vsd who could provide the required torque for your application but really very few will eventually fit truly yours.

Bob

Hi Bob,

Thanks for your reply. Basically i would like to know torque v/s speed characteristics of given hoist load. By knowing torque v/s speed characteristics of the load, then i can select a motor which meets load characteristics. This is what i trying to do.

Guidance in this regard is highly appreciated.

Sri

What you should be able to get from the hoist manufacturer is a torque/speed curve at maximum rated load for that hoist. It is not as simple as just applying a formula, it requires measurement, and that it ususally done by the manufacturer in order to determine maximum capacity. You can interpolate that curve for your given load.

Hi Jraef:

Thanks for your reply. Let us assume a hoist which is rated for 900 lbs and its dead Weight is 180 lbs. Can you guide me what is the method of calculating or measuring starting torque for the above said load? You are welcome to assume other relevant details like pully dia etc.,

Sri

Is this a true application or just a school project.
If you were serious about obtaining data for a true application I am expecting some very firm data. Not, "You are welcome to assume other relevant details..."
I can see this is just a danger waiting to happen.
Hit the local library and do some reading on basic mechanical calculations in determining torque requirements. That way you might learn more than your actual question.
Don't be afraid to learn....go hit the books!!