Variable speed drives

A

Thread Starter

Andrew

Help! I am a complete novice when it comes to electronics but I want to build a tide clock. Now I can either do this mechanically by re-working the clock’s gears, or I can slow down the very small 240v 50Hz induction motor. A guy at work said I can use a Variable Speed Drive to reduce the motor speed by +/-5% to mesh with the lunar cycle. Does anyone know whether VSDs are suitable for this application? Obviously cost is a factor here - I could just look in the newspaper for the daily tides but it wouldn’t be the same fun would it?!

Cheers,
Andrew
 
R
About using the inverter drive as a tool toward the tide clock. The most inverter drives I've worked with rectify incoming A.C. to D.C. then fire the D.C. with SCRs to obtain the varying waveform.. which your probably aware of. I built a BCD clock once which sensed the 60 Hz. then divided this waveform to create an extremely accurate clock. I feel you would be losing this reference.

I could recommend one of three routes to creating a clock. 1) If your into digital electronics create a clock with counter chips like my BCD clock.

2) I've been interested in Basic Stamp programming, I've noticed Nuts and Volts magazine is loaded with Stamp Kits... a clock could possibly be programmed.

3) I've seen a electronic tide clock kit somewhere recently, you could search electronic projects on the internet and probably find a kit for $20-40 bucks... have something presentable on the wall and save yourself abunch of time.

Hope this helps,
ron
 
W

William Sturm

A VS drive sounds like it should work. For low cost
low speed accuracy, you would choose an open loop
volts/hertz drive. For medium cost, but higher speed
accuracy, you would choose an open loop vector drive.
For the best speed accuracy, choose a closed loop
vector drive with a feedback encoder mounted on the
motor.

Bill
 
M

Michael Griffin

The Basic Stamp uses a ceramic resonator, rather than a crystal. The frequency may not be as accurate as you may expect.
 
Top