Help
Help
(OP)
Hi,
I just dont know what type of Stepper Motor to buy (cheap used). I am hoping to use a stepper motor and driver ( advise please on type cost ect ) to drive/tune a Vaccume Variable Capacitor...all I can tell you is the VVC is 2-100pf and 5KV . The motor will rotate very slowly ( dont exactly know how slow ) to tune the ham radio bands on the attached copper magnetic loop, so I REALLY need to know what details the Stepper store will ask for, this I do not know, Im thinking torque, step angle? Voltage? Unipolar or Bipolar???. Im not sure but Ive read some VVC for sale adds, most say 19turns...unsure if this is 9.5 either way or 19 one way and 19 back again? Fact is I have not ordered the VVC as yet. The run from Radio control in shack to antenna is 50feet.
All is not lost...to assist I have attached a photo of my intention.
Advise what you can.
stepper001
http:/ /files.eng ineering.c om/getfile .aspx?fold er=12e1ec5 4-b5cc-4b1 8-9ea7-fe4 5d8b0785a& amp;file=S tepper.jpg
I just dont know what type of Stepper Motor to buy (cheap used). I am hoping to use a stepper motor and driver ( advise please on type cost ect ) to drive/tune a Vaccume Variable Capacitor...all I can tell you is the VVC is 2-100pf and 5KV . The motor will rotate very slowly ( dont exactly know how slow ) to tune the ham radio bands on the attached copper magnetic loop, so I REALLY need to know what details the Stepper store will ask for, this I do not know, Im thinking torque, step angle? Voltage? Unipolar or Bipolar???. Im not sure but Ive read some VVC for sale adds, most say 19turns...unsure if this is 9.5 either way or 19 one way and 19 back again? Fact is I have not ordered the VVC as yet. The run from Radio control in shack to antenna is 50feet.
All is not lost...to assist I have attached a photo of my intention.
Advise what you can.
stepper001
http:/





RE: Help
19 turns X 360 degrees/turn / 0.9 degrees/step = 7600 steps.
Note that the band you cover is divided into that many discrete steps, and is not continuously tunable, no matter how slow you run the stepper.
You can run a stepper with a fairly simple power driver from four bits of a microcontroller, or four bits from the printer port of an obsolete laptop computer, but the programming is a nontrivial effort. Adding half-stepping to that result, doubling the resolution, is a relative triviality, but it may still not be what you want.
I suggest you read up on steppers some more before deciding they will do what you want.
Mike Halloran
Pembroke Pines, FL, USA
RE: Help
RE: Help
Very greatful for the advice thank you. I am going to wait until I locate and purchase my VVC, then I may return, why well it I just learned VVC turning range various a lot.
Regards,
stepper001