Sizing Gearbox for 7.5HP Motor w/1750rpm & 580rpm Input Speed

In summary, the conversation discusses the process of sizing a gearbox for a 7.5HP motor with a pulley and v-belt and connecting it to a right angle worm gearbox with an input speed of 580rpm. The gearbox will need to handle 7.5 HP at 580 RPM and factors such as duty cycle, lubrication, and cooling should be considered when selecting the gearbox. The gearbox should be sized for the lower input speed and more torque, and a larger V-belt pulley can be used to reduce belt tension. The conversation also mentions using a worm box rated for 7.5 HP or more and determining the desired reduction ratio or output RPM.
  • #1
SevenToFive
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If I have a 7.5HP motor running at 1750rpm with a pulley and v-belt and connect it to a gearbox, where the right angle worm gearbox sees an input speed of 580rpm, how would I go about sizing the gearbox?

Am I correct to say that I would size the gearbox for the lower input speed and more torque, and lower output rpm? So I would then calculate the torque generated with a 580rpm input speed, and verify that the gearing is capable of handling the increased torque.

I don't think the gearbox is going to be really seeing the 7.5HP, and if the gearbox becomes overloaded, the belt would probably slip on the pulleys connecting the motor and gearbox correct?

Just looking to confirm that I am on the correct path of thought here. Thanks to everyone who replies.
 
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  • #2
SevenToFive said:
If I have a 7.5HP motor running at 1750rpm with a pulley and v-belt and connect it to a gearbox, where the right angle worm gearbox sees an input speed of 580rpm, how would I go about sizing the gearbox?
The gearbox will need to handle 7.5 HP at 580 RPM. Check the duty cycle, lubrication and cooling of the gearbox.

SevenToFive said:
Am I correct to say that I would size the gearbox for the lower input speed and more torque, and lower output rpm?
Yes, the slower the output shaft, the heavier it will need to be to handle the torque when transmitting 7.5 HP. But you know the input RPM and HP so you can base selection on input shaft torque.

SevenToFive said:
I don't think the gearbox is going to be really seeing the 7.5HP, and if the gearbox becomes overloaded, the belt would probably slip on the pulleys connecting the motor and gearbox correct?
Belts will not slip if they are correctly fitted. If they do slip they will creep during normal operation and so will wear the belts. What section belt and how many will you need for the input torque? Use bigger V-belt pulleys to reduce belt tension or number of belts.

Do you have a link to a list of worm boxes rated at 7.5 HP or more?
What reduction ratio or output RPM is your target ?
 
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  • #3
Baluncore, as always thanks for your help.
 

FAQ: Sizing Gearbox for 7.5HP Motor w/1750rpm & 580rpm Input Speed

1. How do I determine the gear ratio for a 7.5HP motor with an input speed of 1750rpm and an output speed of 580rpm?

The gear ratio can be calculated by dividing the input speed by the output speed. In this case, the gear ratio would be 1750/580 = 3.02.

2. What type of gearbox would be best suited for a 7.5HP motor with these specifications?

The type of gearbox needed would depend on the specific application and requirements. However, a helical gearbox is often a good choice for this type of motor as it offers high efficiency and smooth operation.

3. How is the torque requirement calculated for a 7.5HP motor with an input speed of 1750rpm and an output speed of 580rpm?

The torque requirement can be calculated by multiplying the power (in horsepower) by 5252 and dividing by the output speed (in revolutions per minute). In this case, the torque requirement would be (7.5 x 5252)/580 = 68.45 ft-lbs.

4. What factors should be considered when selecting a gearbox for a 7.5HP motor?

Some important factors to consider when selecting a gearbox for a 7.5HP motor include the input and output speeds, gear ratio, torque requirement, efficiency, and the specific application and operating conditions.

5. Can a gearbox with a different gear ratio be used with a 7.5HP motor with these specifications?

Yes, a gearbox with a different gear ratio can be used as long as it is suitable for the motor's power and speed range. However, it is important to carefully consider the gear ratio and other factors to ensure optimal performance and longevity of the motor and gearbox.

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