×
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

Isolating Motors On One Phase From PLCs On Another Phase

Isolating Motors On One Phase From PLCs On Another Phase

Isolating Motors On One Phase From PLCs On Another Phase

(OP)
If I have a 208VAC AB phase (from a 3 phase supply) powering five 220V motors, is it best to have a step up transformer or just go ahead and use an isolation transformer rated at 208 Or 220 – between the motors and where they tap off of the supply phase.  The main reason I’m doing this is to prevent motor surges, etc. from affecting PLCs on the BC phase of the source supply.

No one at other sites I have visited seems to be able to answer this.

RE: Isolating Motors On One Phase From PLCs On Another Phase

A transformer is not going to prevent a motor surge. Are you trying to protect the PLC power supply from a low-voltage condition brought on by starting the motors, or are you trying to isolate any noise created by the motors when they start? If the later, use a power conditioner on the input to the PLC power supply. It should filter out any transients caused by the motor starting. If it is a voltage dip problem the right power conditioner might work for that too, but you may need a UPS to be sure.

"Venditori de oleum-vipera non vigere excordis populi"


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