×
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

delay cutoff circuits....

delay cutoff circuits....

delay cutoff circuits....

(OP)
Hi im designing a circuit that will eventually allow us to control a motor via a switch that when activated will shut the motor down after 5 seconds if the switch is held open and will then stay shut down untill another push button is hit.

so far i have come up with an RC circuit that works well but im having issues with isolating the RC control circuit from the motor contactor becaure of the inductor

I am interested in wether a Solid state relay would work for this or do they have inductance on the control side?

help !

RE: delay cutoff circuits....

Hi Michael,

I don't know if this will help but I have used an optoisolator in the past to separate the relay coil from the control circuit.

See tutorial on relay drive designs and a little history on relays

http://www.uoguelph.ca/~antoon/gadgets/relays/relays.ht...

RE: delay cutoff circuits....

Suggestion: The Solid State Relay (SSR) might be used depending on its design that would include isolation between its input and the output switching part. The schematic diagram of the solid state relay is needed assess the isolation. The timing on the SSR input side must be compatible with the SSR input parameters.

RE: delay cutoff circuits....

(OP)
thanks for the info

so a SSR is an optoisolated voltage controlled voltage source with very little input impedance?  

if so then thst would be perfect.

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