I personally use the red lion IMI series coupled with a pnp type hall effect proximity sensor to detect the key way on the output shaft, i have found that Red lion instrumentation has provision for data to be sent via twisted pair to a remote display or to a chart recorder...
My suggestion after reading through all the messages here, and most are fine recommendation, but i see we fail to answer the question you originally ask,are there standards?
Yes and no.
But to make this a short but effective reply, i would like to suggest this.
Any type of sensor of critical...
The best bet, if it is determined that the y-d contactors are satisfactory, and usually 9 out of 10 times, the fault lies in the winding, believe it or not, the motors on mixer, especially those of hobart, and others, are prone to dielectric failures of the winding, which means the resistance...