ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat Box
Recent Posts
New tool
by gfretwell - 10/19/20 03:43 PM
Where is Everyone?
by Bill Addiss - 10/17/20 07:04 PM
Beyond Belief
by gfretwell - 09/27/20 12:03 AM
Questioning the electrical norms
by LongRunner - 09/23/20 06:38 AM
Smoke & mirrors?
by HotLine1 - 09/21/20 03:42 PM
New in the Gallery:
Facebook follies, bad wiring
FPE in Germany pt.2
Who's Online Now
0 registered members (), 21 guests, and 18 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
Overcurrent Protection #80179 03/12/02 07:28 PM
Joined: Oct 2000
Posts: 2,749
Joe Tedesco Offline OP
Member
What types of overcurrent devices do you install to protect motor circuits?

Do you have any comments about fuses or circuit breakers?

[This message has been edited by Joe Tedesco (edited 03-13-2002).]


Joe Tedesco, NEC Consultant
2017 / 2014 NEC & Related Books and Study Guides
Re: Overcurrent Protection #80180 03/13/02 12:27 PM
Joined: Oct 2000
Posts: 2,749
Joe Tedesco Offline OP
Member
What is a design E motor, and required overcurrent protection for one?


Joe Tedesco, NEC Consultant
Re: Overcurrent Protection #80181 03/13/02 09:17 PM
Joined: Jan 2002
Posts: 163
D
dana1028 Offline
Member
Design E motors - in my motor class this was discussed last week...they said this is an example of the code getting ahead of technology...kind of...a few years ago there was talk of developing these super efficient (E) motors...turned out these motors were so expensive to develope no one wanted to buy them....so...no such motors are on the market.

Re: Overcurrent Protection #80182 03/13/02 10:10 PM
Joined: Mar 2002
Posts: 582
R
Ron Offline
Member
I like to use a motor circuit protector (aka MCP or cirucit breaker with instantaneous only) with a solid state overload. This allows for the most flexibility and ease of maintenance.

Although manufacturers like Baldor have made Super E - Premium efficiency motors, I believe they are still Design B. Design letter indicating the shape of the tourque speed curve characteristics.


Ron
Re: Overcurrent Protection #80183 03/14/02 02:09 AM
Joined: Oct 2001
Posts: 597
E
ElectricAL Offline
Member
Joe,

As I recall, the Design E NEMA spec was rescinded. . .about a year ago. I read it in a trade journal (can't find the one right now) and heard it from a State Electrical Inspector who was leading a Code Class, February, last year.

Al


Al Hildenbrand
Re: Overcurrent Protection #80184 03/14/02 08:22 AM
Joined: Aug 2001
Posts: 31
C
ctolbert Offline
Member
To comment on the first question:

The thing I deal with everyday is the use of IEC starters and the MSP (motor starter protector).

The reason I bring this up, the MSP does not meet UL 489. Which means that it cannot be used as a stand alone SSPD (short circuit protective device.) In Europe, it is recognized as such. It's really confusing.

It can be used in the context of NEC 430-53c which is group motor rating. However, I get at least 10 calls a week on use of this within a motor control circuit.

I came to the realization, that the cost of these devices ($19.00 - $120.00) makes them such a commodity...that I will be seeing more and more of them in place of NEMA devices.

It's not a bad thing, if used correctly.

IMHO,
Carl


Carl Lee Tolbert
Technical Support
AC Drives
Automationdirect.com
Your source for the most practical automation products at almost-free pricing, delivered by 11 a.m., just by clicking a mouse.
PH: (770)844-4200
Fax:(770)886-3199
www.automationdirect.com
Re: Overcurrent Protection #80185 03/14/02 08:39 PM
Joined: Oct 2000
Posts: 3,631
Admin Offline
Administrator
Member
(Posted for ctolbert)

[Linked Image]

Quote
This shows what the MSP looks like. I also wrote a paper on this, that you may be interested in.

- Carl

[This message has been edited by Webmaster (edited 03-14-2002).]


Featured:

2020 National Electrical Code
2020 National Electrical
Code (NEC)

* * * * * * *

2020 Master Electrician Exam Preparation Combos
2020 NEC Electrician
Exam Prep Combos:
Master / Journeyman

 

Member Spotlight
Tom
Tom
Shinnston, WV USA
Posts: 1,044
Joined: January 2001
Show All Member Profiles 
Top Posters(30 Days)
BigB 3
Popular Topics(Views)
270,700 Are you busy
204,940 Re: Forum
193,051 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.7.3