×
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

Motor nameplate data and drive question

Motor nameplate data and drive question

Motor nameplate data and drive question

(OP)
I recently received a motor with nameplate in two parts.

Part 1:
Interter data
20 HP
6-60 HZ
460 V
23.6 Amps
1.0 service factor

Part 2
Sine Data
25 HP
60 HZ
460 Hz
29.7 Amps
1.15 service factor

The motor will be installed using a standard combination started (60 Hz) not a VFD.  

Question 1 - Should the conduit, wire, starter, fuses, etc. be sized for per the NEC based on the 25 HP motor?

Question 2 - Is it a code requirements that if a drive is being installed on a piece of equipment with a standard motor (motor not rated by inverter service) that motor be replaced with a motor that is rated for inverter service?


RE: Motor nameplate data and drive question

To install the motor for use on utility power, I believe you need to size per NEC based on the 25 HP nameplate marking.

NEC does not require the use of a motor rated for inverter service when connecting the motor to a VFD. If the motor needs to be UL listed, such as for use in a hazardous (classified) location, I believe that the UL label will be valid only  for a motor that is rated for inverter service.

RE: Motor nameplate data and drive question

That's right. I also think that what that nameplate is saying is that it is an inverter rated motor, but not at 25HP. Instead they are saying that as an inverter motor it is only rated for a 20HP load.

http:/www.jraef.com
Eng-Tips: Help for your job, not for your homework  Read FAQ731-376 pirate

RE: Motor nameplate data and drive question

Use:
Inverter Data  when used with VFD.
Sine Data  when connected to the utility or fix frequency source.

RE: Motor nameplate data and drive question

The derate on the inverter is probably due to a constant torque requirement over 6-60hz.  It's probably good for 25hp variable torque 6-60hz or 25hp constant torque 15-60hz.  Reliance often rates and labels their motors that way.

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