ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat
Recent Posts
Increasing demand factors in residential
by tortuga - 03/28/24 05:57 PM
Portable generator question
by Steve Miller - 03/19/24 08:50 PM
Do we need grounding?
by NORCAL - 03/19/24 05:11 PM
240V only in a home and NEC?
by dsk - 03/19/24 06:33 AM
Cordless Tools: The Obvious Question
by renosteinke - 03/14/24 08:05 PM
New in the Gallery:
This is a new one
This is a new one
by timmp, September 24
Few pics I found
Few pics I found
by timmp, August 15
Who's Online Now
0 members (), 260 guests, and 19 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
Joined: Dec 2003
Posts: 36
D
Member
Would anyone know how to size the resistors on a Wye start/delta run closed transition starter? Say for a 50 Hp 230V motor?

Stay up to Code with the Latest NEC:


>> 2023 NEC & Related Reference & Exam Prep
2023 NEC & Related Reference & Study Guides

Pass Your Exam the FIRST TIME with the Latest NEC & Exam Prep

>> 2020 NEC & Related Reference & Study Guides
 

Joined: Oct 2000
Posts: 2,723
Likes: 1
Broom Pusher and
Member
I believe the Resistors would be sized ("size" = Resistance value - in Ohms), so as to allow the same level of Current that the "Wye" configuration does.

Example:
Motor's FLA = 130 Amps
Starting (Wye Connection) Ampere = +/- 75 Amps
Resistors are sized to allow +/- 75 Amps at rated Voltage.

I am not 100% sure on this, so let me find some references, then reply back.

Scott


Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!
Joined: Dec 2003
Posts: 36
D
Member
That makes sense to me. The smaller you make them the closer to normal current you have. The next question is Watt ratings. The resistors are only in the circuit for a split second in the transition between wye and delta so would you need full power ratings(Peak I^2 R) on them?


Link Copied to Clipboard
Powered by UBB.threads™ PHP Forum Software 7.7.5