×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

variable duty cycle dc motor timer

variable duty cycle dc motor timer

variable duty cycle dc motor timer

(OP)
Can any one help with the design of a timer that would turn on a small DC motor for 1 minute, followed by a variable 20 - 40 minute rest period, to cycle continuously.
I am fully competent in building the building side, but the maths involved escapes me.
Thanks in anticipation.

RE: variable duty cycle dc motor timer

A 555 is probably the easiest solution...

RE: variable duty cycle dc motor timer

There are off the shelf units to do so if interested, digital time delay cycle timers that have programmable on/off times and number of cycles to execute with the option of repeat indefinitely.

Wheels within wheels / In a spiral array
A pattern so grand / And complex
Time after time / We lose sight of the way
Our causes can't see / Their effects.

RE: variable duty cycle dc motor timer

(OP)
Thanks,analogkid2digitalman .
Any pointers to who, and how much?
Alternatively, would still be interested in just the circuit diagram.

RE: variable duty cycle dc motor timer

Robert,

Check out relays from the likes of Crouzet and Omron. Their multifunction timer relays have the functionality that you seek, and they may have a specific type which is cheaper and does exactly what you want without the other features.

Expect to pay about 70GBP or so. The economics really depends how you value your time building it against the ease ofa ready-made solution. 70GBP doesn't buy much development time at commercial rates.


----------------------------------

If we learn from our mistakes,
I'm getting a great education!

RE: variable duty cycle dc motor timer

Search "Google images" using -  555  "duty cycle"

About 30 schematics.

RE: variable duty cycle dc motor timer

Macromatic TR-63xxx or TR-65xxx repeat cycle timers, about $90 from Newark

http://www.macromatic.com/literature/catalog/pdf/2....

Also came across an Amperite 12DF/FHDFA for about $55, also from Newark.

These may be overkill (handle up to 10A loads), just a suggestion if you need a minimum of hassle.

Good Luck

-Pete

Wheels within wheels / In a spiral array
A pattern so grand / And complex
Time after time / We lose sight of the way
Our causes can't see / Their effects.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources