×
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

Volt Free Contact

Volt Free Contact

Volt Free Contact

(OP)
Does remote start/stop of equipment is possible through volt free (Dry) contacts provided in equipments' control panel? I want to start/stop the pump through BMS. Manufacturer states that he has provided Volt free contacts for start/stop in pump's control panel.

RE: Volt Free Contact

Yes. You run the hot line to the volt free contact with a voltage and current that the contact is rated for, and the switched-leg to the line side of your starter coil, and when the BMS shuts the contact, the motor starts. Be aware of the ratings on the contact. They may not be adequate to work with large inductive starter coils. Not all contacts are created equal.

xnuke
"Live and act within the limit of your knowledge and keep expanding it to the limit of your life." Ayn Rand, Atlas Shrugged.
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.

RE: Volt Free Contact

(OP)
Thanks xnuke,

But our engineer says, volt free contacts are for taking status only. You cant provide command via volt free contacts. Any advise pls.

RE: Volt Free Contact

Your engineer may be correct. Often, low-rated contacts are provided for status only. Without a schematic and bill of material for the control panel, I doubt anyone can advise you. Can you share them?

xnuke
"Live and act within the limit of your knowledge and keep expanding it to the limit of your life." Ayn Rand, Atlas Shrugged.
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.

RE: Volt Free Contact

What the supplier might mean is volt free switching where you supply the volts and current that activate a switch on the other side of the relay / switch in the pump panel. it's a bit of a strange way of putting it, but just separates the two systems. Essentially you're powering the solenoid bit of the realy and the pump panel contacts to start / stop are inside the pump panel.

As noted above you need to know what the contacts need in order to make the contact - 12VDc or 240V AC or something else and maximum current the contacts can take.

Simply saying there are a pair of contacts here which start / stop the pump without giving you the voltage and current rating is next to useless.

Also is the relay latched or does the pump stop on loss of volts?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Volt Free Contact

I just re-read the original post. Are there two control panels - one for the BMS and one for the pump? If so, I was wrong in my previous post. The dry contact would need to be in the BMS panel, and receive and switch a hot leg wire from the pump control panel.

xnuke
"Live and act within the limit of your knowledge and keep expanding it to the limit of your life." Ayn Rand, Atlas Shrugged.
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.

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

eBook - Efficient and Effective Production Support with 3D Printed Jigs and Fixtures
Jigs and fixtures offer manufacturers a reliable process for delivering accurate, high-quality outcomes, whether for a specific part or feature, or for consistency across multiples of parts. Although the methodologies and materials for producing jigs and fixtures have evolved beyond the conventional metal tooling of years past, their position as a manufacturing staple remains constant due to the benefits they offer. Download Now
Overcoming Cutting Tool Challenges in Aerospace Machining
Aerospace manufacturing has always been on the cutting edge, from materials to production techniques. However, these two aspects of aerospace machining can conflict, as manufacturers strive to maintain machining efficiency with new materials by using new methods and cutting tools. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close