gear reduction/increaser vs pulley????

[budder]

I'm writing this post for some help due to my lack of knowledge. I have been working on a project in my garage that I am using a 5hp 240v single ph motor at 3250 rpm. max 15amp continuous. the issue is that I am running this project through a pulley system in order to get the desired rpm output at the project (which is roughly 1400rpm). In order for the project to be effective I need to increase the rpm at the output by 300-400 rpm (I can only get to about 1000 without exceeding ampacity). when I get to that point I exceed the 5hp or under requirements that I am looking for and ultimately exceed amp limits. I have tried many combinations of pulley sizes and even a gear reduction box which only increased the draw. my question is: is it possible to overcome amp to hp ratio with a gear/pulley system or is it always relative? for example if I go to a pulley system or gearing reduction/increaser would this take the load off of the motor and reduce the amp draw? or is there another way to achieve this? any help would be appreciated.

 

[MikeHalloran]

Uh, 240/15 corresponds to ~4.82HP, with no conversion losses.

You can't get 5HP out of a 4.8HP pipe.

Using a four pole motor at ~1750 rpm and no belts or gears will get rid of the losses external to the motor, so all you need to buy is a 4 pole motor with ~120 pct efficiency. ;-)

Reduce the motor rpm a little more and use it start a Diesel.



Mike Halloran
Pembroke Pines, FL, USA

 

[eromlignod]

It's all about power. If you want to drive a load that has the same torque requirements, but at a higher speed, it takes more power (Power = torque x rpm). No matter what mechanical advantage you use, power in = power out. You can't create extra energy from nothing.

The upshot is: you need a bigger motor.

Don
Kansas City