×
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

float contact controls

float contact controls

float contact controls

(OP)
I'm installing a couple of floats in a process water pit. I need the floats to active a light and turn a pump on. Is this possible with one float? I guess to make it clearer, can you control two seperate items with one float??

Thanks in advance

RE: float contact controls

If the float has multiple contacts you can do that directly.  If the float only has one contact, use that contact to drive a relay and let the relay control the other items.

RE: float contact controls

Using an interposing relay would be good practice anyway: relays are usually cheaper and less hassle to replace when, for instance, a pump motor fault occurs and passes a high fault current through the switch. If the pump is anything over a couple of hundred watts you should be using a contactor for switching the pump instead of a relay. You could drive the lamp from a spare pole or auxiliary switch mounted on the contactor.

You could in theory just parallel the lamp and the motor if they were of compatible voltage, but this would be a real cheap and dirty way to do things.

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

One day my ship will come in.
But with my luck, I'll be at the airport!

RE: float contact controls

There are mechanical float switches that provide an adjustable dead band of operation, so that you can use one device that has a single contact which closes when the level reaches "X" height, but does not reset (open) until the level is "X + Y" height. This technical information article explains how they work and what the issues are to applying them, but you can find other manufacturers by looking for "sump operation" level controls.

[quote http://www.ab.com/en/epub/catalogs/12768/229240/2286210/229278/tab3.html] AB Float Switch article link [/quote]

Eng-Tips: Help for your job, not for your homework  Read FAQ731-376

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