×
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

Steel Slip Rings for Synchronous Motor
2

Steel Slip Rings for Synchronous Motor

Steel Slip Rings for Synchronous Motor

(OP)
What is the recommended steel grade for DC field slip rings?
This is a Synchronous motor, 1750HP, GE, 1200 rpm, 60 HZ, 6600 Volts, 149 Amperes, Field DC-Volts 125 and Field DC-Amps 960. The Outside diameter of the rings is 11.5" and the width is 1.125".

RE: Steel Slip Rings for Synchronous Motor

I don't know the answer. I haven't heard of steel slip rings.  Why use steel instead of copper or bronze?

=====================================
Eng-tips forums: The best place on the web for engineering discussions.

RE: Steel Slip Rings for Synchronous Motor

There are about 7 different classes of materials (includeing Cu)that have been used for slip rings.

STEEL 0.21%C or 1% C with 1% Cr. This is usually used for turbo alternators where high hoop stress may be encountered.
However oxidation is a problem with this material.

Stainless Steel Following is good for poor atmospheric conditions
18% Cr 8% Ni
or
25%Cr 12%Ni
or
17%Cr 10% Ni
Do not combine with Mo and/or W, not advised.

RE: Steel Slip Rings for Synchronous Motor

aolalde, I've looked this up in my Morganite book "Carbon Brushes and Electrical Machines", which states:

"The two steels used are classified as either low carbon (0.21% and known as "20" carbon type) or high carbon (1.0% carbon plus 1.0% chromium)"

- actually this is the same as quoted by DougMSOE.

My older edition of the same book states that nickel steels are used in order to get the necessary tensile strength, and that brush contact and load current distribution is improved by the use of helical grooves in the running surface of the ring.

Incidentally it also says that because the machine operates above critical speed, ring grinding should be carried out at or near running speed.

RE: Steel Slip Rings for Synchronous Motor

(OP)
UKpete & DougMSOE, Many thanks for you for help.

Epete. Due to ambiental contamination which attacks copper alloys.

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