I have a WoodGun E140 and would like to be able to control the speed of the draft fan. The boiler has a single phase Baldor 1/3 HP motor running at 3450 RPM. I have not been able to find a cost effective drive (VFD) that will work with a single phase motor. There are some very low cost VFD units that work with 3 phase motors and 3 phase motors are not that expensive, so this seems like the way to go.
I am wondering if anyone has experience with the low cost ($100) VFD's such as this:
http://www.automationdirect.com/static/specs/gs1drives.pdf
The other concern I have is with motor sizing. The small 3 phase motors are rated for HP at 1800 rpm. A 1/4 HP motor at 1800 PRM makes more torque than my 1/3 HP motor, however the 3-phase motors I was looking at claim they can maintain their rated HP at 2x the base speed (or 1/4 hp at 3600 RPM). I would have expected the HP output to go up with RPM. In any case, I am wondering what will happen with the VFD if the loading of the motor exceeds the output rating of the motor or VFD? Will the motor be shut down, or will it be slowed down to a sustainable power level?
Has anyone else done a similar conversion?
Thanks,
Scott B.
I am wondering if anyone has experience with the low cost ($100) VFD's such as this:
http://www.automationdirect.com/static/specs/gs1drives.pdf
The other concern I have is with motor sizing. The small 3 phase motors are rated for HP at 1800 rpm. A 1/4 HP motor at 1800 PRM makes more torque than my 1/3 HP motor, however the 3-phase motors I was looking at claim they can maintain their rated HP at 2x the base speed (or 1/4 hp at 3600 RPM). I would have expected the HP output to go up with RPM. In any case, I am wondering what will happen with the VFD if the loading of the motor exceeds the output rating of the motor or VFD? Will the motor be shut down, or will it be slowed down to a sustainable power level?
Has anyone else done a similar conversion?
Thanks,
Scott B.