Stueeee
Old git
- Messages
- 1,092
- Location
- N W Kent
I have had a 'DoAll' vertical bandsaw for a long time, which has always given me great service. However, the speed adjustment is by a cone pulley setup which is both really awkward to adjust (a handwheel round the back where I store various sawbands) and quirky, in that any speed adjustment seems to go in leaps and bounds. So I have always used it at a bandspeed of about 250 FPM, which is fine for cutting steel etc. with an M42 HSS band, but could usefully be a great deal faster when I'm cutting Aluminium or wood.
My idea is to replace the existing 415v four pole 3/4 HP motor, with a 1 HP 4 pole motor and change the pulley arrangement to provide static gearing which delivers the existing 250ish FPM @ 30HZ, then adjusting the frequency up to 90HZ to achieve the speed increase for cutting plywood etc. Is 30-90HZ likely to be sustainable on the motor for reasonable periods of time? the idea of increasing the motor size from 3/4 to 1HP is in recognition of the power reduction which will occur at low frequency/RPM, the existing 3/4HP motor has never shown any signs of struggling even cutting heavy steel plate.
I have a new 415V in 415V out VFD as in the photo below:
I have absolutely no experience with VFDs, so configuring this one, using its 'Chinglish' manual looks like it might be 'interesting' for me. I won't be needing the jog, reverse or any other fancy features. But I will want to use a remote potentiometer which I intend to install in my home made speed indicator. The VFD manual shows a remote pot as a configurable option, but no resistance for it is specified -working on the basis that most of these VFDs are similar inside, what would the potentimeter resistance value typically be?
Thanks for looking, I'd welcome your views, even if they turn out to be 'if was going there, I wouldn't start from here'
My idea is to replace the existing 415v four pole 3/4 HP motor, with a 1 HP 4 pole motor and change the pulley arrangement to provide static gearing which delivers the existing 250ish FPM @ 30HZ, then adjusting the frequency up to 90HZ to achieve the speed increase for cutting plywood etc. Is 30-90HZ likely to be sustainable on the motor for reasonable periods of time? the idea of increasing the motor size from 3/4 to 1HP is in recognition of the power reduction which will occur at low frequency/RPM, the existing 3/4HP motor has never shown any signs of struggling even cutting heavy steel plate.
I have a new 415V in 415V out VFD as in the photo below:
I have absolutely no experience with VFDs, so configuring this one, using its 'Chinglish' manual looks like it might be 'interesting' for me. I won't be needing the jog, reverse or any other fancy features. But I will want to use a remote potentiometer which I intend to install in my home made speed indicator. The VFD manual shows a remote pot as a configurable option, but no resistance for it is specified -working on the basis that most of these VFDs are similar inside, what would the potentimeter resistance value typically be?
Thanks for looking, I'd welcome your views, even if they turn out to be 'if was going there, I wouldn't start from here'