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Locksley Robinson
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Join Date: Nov 2006
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Calculation for sizing hoist

07/10/2008 11:40 AM

Could you suggest a formula for calculating the hp requirement for the sizing of a rope hoist to lift a load of 500Kg at 16 m/min over a height of 27m.

Thank you for your help
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Anonymous Poster
#1

Re: Calculation for sizing hoist

07/10/2008 11:10 PM

Dear friend,

pls. refere the DESIGN DATA BOOK By: PSG COLLAGE OF TECH. INDIA.

Regards,

Mitul Patel
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Johan van Niekerk
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#2

Re: Calculation for sizing hoist

07/11/2008 1:28 AM

The power you need is:

P = M g v/n

M = mass in Kg

g = gravity accelleration 9.81 m/s/s

v = velocity in m/s

n = effeciency of hoist.

If the hoist is one that does not drop the weight when stoppe the efficiency is less than 50%.

You will need P = (500 x 9.81 x 16/60) / 0.5

= 2.616 KW or 3 KW to allow for safety.

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Locksley Robinson
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#3
In reply to #2

Re: Calculation for sizing hoist

07/11/2008 10:09 AM

Thank you Johan, this has been helpful. In my further research, I have seen where most manufacturers of this type of electric winch recommend 1.5-2 KW for lifting a 500 Kg load. This would result in efficiencies of approx 60 to 80% (based on your formula). Is this reasonable?
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Johan van Niekerk
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#4
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Re: Calculation for sizing hoist

07/14/2008 1:14 AM

If the efficiency is higher than 50% then the hoist will reverse when stopped. For this type of hoist you need a braking mechanism which is usually only done on larger hoist motors.

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