I collect social security as m y only income. I also pay alimony to an ex spouse. Is there a percentage maximum that she can collect from my social security?:

What kind of social security is it ? There is one kind that is a retirement benefit and another that is a disability benefit.

It is a retirement benefit

It seems its up to the max levels set by the state the order is in. You can look here.

Social Security Act §459 (http://www.ssa.gov/OP_Home/ssact/title04/0459.htm)