Dear Farad,
1.If you know your load in kw, you can calculate armature current by assuming certain value of effeciency.
Effeciency = (Va* Ia) / kW
2. For calcuating its speed, you should know total no. of Conductors in armature. It is quite difficult to find out, without removing armature...
Mr. Beatcan,
List out causes of failure then you can pinpoint what could be problem with that motor.
If possible try to post some more information, so that any one of us can analyse and guide accordingly.
Mr. Farad,
Actually i am not able to understand the purpose of your question. If you are able to get values of the all the parameters, then it would be helpful.
To be frank with you, really i am not able to understand your question even though i was a designer of DC motor.