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".
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
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RE: Steel Slip Rings for Synchronous Motor
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
"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
Epete. Due to ambiental contamination which attacks copper alloys.