×
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

generate a warning for current drawn

generate a warning for current drawn

generate a warning for current drawn

(OP)
Dear all,
I have posted this in the motors and motor controls engg, but decided to post in this forum as well to search for a solution.

I have a chiller compressor motor monitored by a CT 800/5amp, 15va burden capacity.
I want to know is there any readyly available control unit which can be used to monitor the motor current using the mentioned CT and generate a warning for current drawn by the motor 400-800amp, (value settable). May suggest a suitable circuit to achieve the goal.- Regards.

RE: generate a warning for current drawn

A link to the current transformer would help.
Do you mean something like this one?

http://www.brunelcorp.com/ECC/CTX.HTM

It seems that you just put a low value resistor across the current transformer output and you will get a suitable AC signal to monitor. If you are going to make your own detector it will consist of a few resistors, a few capacitors and a comparator. You will also need some sort of power supply like a plug top 9V DC supply or similar. Is this an acceptable type of solution or do you just want to get an off the shelf module?

RE: generate a warning for current drawn

(OP)
Thank you logbook for the reply.
I really prefer to get an off the shelf solution, but as interested to do it by myself also provided I get a workable circuit. Your help for this is most welcome.
Regards.

RE: generate a warning for current drawn

honeykuwait,

an off-the-shelf solution like the one suggested by skogs is going to be cheaper and easier if you only ever want to make one. You should search for one that does what you want. If no such beast exists then by all means go ahead and design one. In this case you will have to decide on or state the following:

1) What is the maximum primary current that is not a fault?
2) What is the minimum primary current that is a fault?
3) What is the nature of the alarm? (500W light bulb, serial data stream to a computer, 20mA LED current?)

If the answers to (1) and (2) are too close together (say within 20%) adjustment/calibration will be necessary.

 

RE: generate a warning for current drawn

(OP)
Hi Logbbok,skogsgurra (Electrical)
Thanks for the advise, I found CR4395 shall meet my requirement.I will come back after using the CR4935.

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