Does anyone know what the max safe rpm for my new 1750 rpm motor is. My VFD does allow me to overclock it. Thanks guys and I will post pics tomorrow.
1750 is max because the synchronous speed is 1800rpm with 2.8% motor slip the nameplate data is based on full load continuos duty motor ratings. Any higher will create heating in the motor windings and eventually fail the motor.
what are your motor specs icho ? There are some good posts' out there to read (if you havent already)..........about motor speeds , bearings , do's and don'ts
Icho if you run your motor at synchronous speed 1800rpm there will be little to no torque produced by your motor which won't do any good it it's the lagging flux current created by motor slip is what creates torque and gives you constant horse power for driving a load. If you run above synchronous speed you can only proportionally run again at 2.8% above rated base speed and in fact the motor will become asynchronous and therefore become a generator actually producing the same amount of power and lowering torque characteristics. The only reason to do this would be for power factor correction decreasing the inductive reactance of the circuit and drawing less power (watts).
Hmm I think you lost me at synchronous. Lol. I'm hoping to play with it later today and see how it grinds a blade. using it as is seems to work good with plenty of power. I am considering adding pulleys in the future. I just have to fugure out how much torque I will lose. Thanks for the info.
I've been reading quite a bit about overspending a motor so I decided to email the supplier. Here's what they got back to me with. You can overspeed the motor with the same horsepower up to 2700 rpm. But you will not have all the shaft torque. The torque *will decrease *over 1750 rpm on a way that is inversely proportional to the rpms. * The formula to apply is:* Torque [lb-ft] = HPx5250/rpm * Rpm **** ************* Torque 900 **rpm = ****** 3 lb-ft 1750 rpm =******* 3 lb-ft 2000 rpm =******* 2.6 lb-ft 2400 rpm = ****** 2.18 lb-ft 2700 rpm =******* 1.94 lb-ft* ( 64%) It is safe to go up to *5000 rpm* to but the torque will really *decrease faster than the ratio here. We do not have a formula to determine that. Now keep in mind that this is for my specific set up so before you try to speed up your motor do some. Research to prevent possible damage to your set up. This is great news for me cause now I should be able to get the sfm I need safely and still have the torque I need with my 1hp motor. I've been cleaning my garage the past couple days but when I get a chance I will try to post a video. So far I'm lovin my new grinder. Hope this helps you guys out.
