osvaldo1961
Plastic
- Joined
- Apr 5, 2019
Hi everybody, (and excuse me for my English)
First timer, I recently got a single phase output (so said the seller) VFD in order to upgrade (a bit) my big wood lathe whose motor is a 1.8 Hp PSC motor.
I have been playing around with that, and I would like to share with you my experience.
First option offered is to simply connect two VFD terminal with motor.
Result:
1. Many vibration out of the range in between 40-80 hz
2. Below 20 Hz it stop itself do no torque available
3. Reverse from VFD is not possible; it will stop and start again in the same way.
Second option offered is to remove capacitor and supply its winding with a second Phase supplied from the third output terminal. So you are working with a true 2 Phase motor
A bit better!
1. Few vibration from 10 to 100 Hz
2. Not so bad torque between 30-75 Hz
3. But anyway the slippage under load is too big to be honest.
Outstanding (a least for me)! I discover that this VFD can be set to give a 3 Phase output also!
So I tested with a little smaller 3 Phase motor and I discovered, to say that, the warm water!
As everybody says in forums you can’t use a 1 (or even 2) Phase motor with VFD and get good performance, not too far from 3 Phases option.
Everybody say that, but nobody apparently knows why, or at least they did’t say!
Ok, if you keep the capacitor and change frequency you will lose the correct angle between the 2 Phases and with so, performance.
But, if you remove capacitor and you supply the motor with 2 Phases at 90° straight from the VFD which one are the deep technical reasons you lose so much torque, even at standard frequency, and you get so much slippage compared with connection straight from plug?
Are anybody able to give me an explanation?
Thank a lot and Best regards
Osvaldo
First timer, I recently got a single phase output (so said the seller) VFD in order to upgrade (a bit) my big wood lathe whose motor is a 1.8 Hp PSC motor.
I have been playing around with that, and I would like to share with you my experience.
First option offered is to simply connect two VFD terminal with motor.
Result:
1. Many vibration out of the range in between 40-80 hz
2. Below 20 Hz it stop itself do no torque available
3. Reverse from VFD is not possible; it will stop and start again in the same way.
Second option offered is to remove capacitor and supply its winding with a second Phase supplied from the third output terminal. So you are working with a true 2 Phase motor
A bit better!
1. Few vibration from 10 to 100 Hz
2. Not so bad torque between 30-75 Hz
3. But anyway the slippage under load is too big to be honest.
Outstanding (a least for me)! I discover that this VFD can be set to give a 3 Phase output also!
So I tested with a little smaller 3 Phase motor and I discovered, to say that, the warm water!
As everybody says in forums you can’t use a 1 (or even 2) Phase motor with VFD and get good performance, not too far from 3 Phases option.
Everybody say that, but nobody apparently knows why, or at least they did’t say!
Ok, if you keep the capacitor and change frequency you will lose the correct angle between the 2 Phases and with so, performance.
But, if you remove capacitor and you supply the motor with 2 Phases at 90° straight from the VFD which one are the deep technical reasons you lose so much torque, even at standard frequency, and you get so much slippage compared with connection straight from plug?
Are anybody able to give me an explanation?
Thank a lot and Best regards
Osvaldo