[TCML] July 4th and why not to be in a hurry

[David Rieben]

Phillip, Bart,

sniperz:

----- Original Message ----- 
From: "bartb" <bartb at classictesla.com>

> Hi Phillip,
> 
> The VFD receives 1 phase 240V power and outputs 3-phase 230V power to 
> the motor. The frequency is changed which changes the speed of the 
> motor. It all  built in to the VFD. I simply use a small potentiometer 
> mounted on the control panel to vary the analog signal and the drive 
> takes this information and vary's the frequency accordingly. The PLC is 
> the brains, but it's mainly for errors. The main reason I use it is that 
> if the VFD gets an error of any type, the motor will either stop within 
> 5 seconds or freewheel to a stop. The VFD outputs an error signal which 
> I feed into the PLC. If there are any errors, it will shut down the main 
> contactor to the coil. While I was at it, I threw in a deadman switch 
> (low level signal), enable key, etc.
> 
> Adam Minchey also runs 3-phase via VFD on his coils. One could also use 
> a DC motor and simply vary the voltage for bps control.

Yep, I use a permanent magnet DC treadmill drive motor 
powered through a variac and a FWB rectifier, which pretty
much gives an infinite range of speed control. Not quite as many 
"bells and whistles" as is available with a VFD drive system
but never the less, it still gets the job done ;^)

> Take care,
> Bart

David