This is crazy but since i work under someone else i have no choice but to ask for help. My boss has a 3450 RPM, 60 cycle, 1 phase, 115/230 volts, 12.4/6.2 amps. Here's what we need to do other than buying a different motor. A pig will be roasted under a BBQ pit. I need to use this power-full motor and add some kind of extra belts to pulleys or something like that. We need to make this pig rotate at a much and i mean much slower rate so i cooks nice and thoroughly. My dead line is 6/26/09 If anyone has any brilliant ideas plz help.
Wow Juan, let me tell you something, I have no clue how in HELL you got this job if you cannot solve this simple problem. First of all, I would recommend you get a different motor, because the reduction that you would need for this would be massive. I'm not sure if this is possible. I'm sure you know of gear ratios? Well the same thing applies with timing belts and their sprockets. If you have a small sprocket on the motor and then a larger sprocket on the other side, then the larger sprocket turns slower. So you would essentially do that, or you could do multiple reductions. That would be to say that if you put a small sprocket on the motor, and then put a large sprocket on a shaft, then you can put another small sprocket on the shaft and wrap and belt it with another large sprocket. This is called compound gearing. So using that method, you can reduce the speed of the motor. Now, considering this is a pig and it's roasting, I'm thinking that the RPM should be somewhere about 6-10. So the gear ratio should be about 345. Good luck.
You can build one if you have the time, and $. Start by putting a small pulley on the motor shaft, and have it turn a large pulley. On the same shaft of the large pulley, have another small pulley, which turns another large pulley that's attached to the shaft, the pig is on. It will give the motor ample power to turn the pig, and it will slow the rpm's way down.
The motor you are describing is a synchronous motor; the speed cannot be changed easily. Variable frequency as suggested $$$$ can do for a bit, maybe 20% So you are stuck with the gear thing, I would suggest that you get a few BBQ motors at a local store because it has all the gearing. A few, because they may not last for the entire job depending on how well balanced is the load (the pig) If the load is well balanced, meaning that the effort is constant throughout the revolution then the BBQ motor will do fine. If the motor has to break the rotation in some portion and supply enormous torque in other portions it will die on the job I hope this answers your question
This Site Might Help You. RE: How can i slow the RPM on an AC motor? This is crazy but since i work under someone else i have no choice but to ask for help. My boss has a 3450 RPM, 60 cycle, 1 phase, 115/230 volts, 12.4/6.2 amps. Here's what we need to do other than buying a different motor. A pig will be roasted under a BBQ pit. I need to use this power-full...
1. decrease the frequency by power-electronic devices or motor-generator systems this is the classical way but not economical for you 2. replacing the motor with another, which has more poles , u can buy a 875 rpm AC motor with 4 couples of poles with same nominal power ( it will be a little larger) 3. u can use a gear box 4. u can replace the motor with a DC motor (with rectifier )and simply control it with input voltage
