I have a small 1.5hp 230/460V motor which is wired for 460V. Upon performing an IR test as part of the acceptance testing of this new motor we noticed that we were getting low readings when tested at 1000V. The highest readings that were reported were 13megaohms.
I instructed the technicians to then perform a DAR test on the motor. The results for this were as follows:
A = 30 sec =9.1
60 sec 14.2
DAR = 1.56
B= 30 sec = 14.1
60 sec = 16.3
DAR = 1.15
C= 30 sec = 14.0
60sec = 16.2
DAR = 1.15
Only the A phase DAR reading was over 1.4 which appeard to be good but the other two were below 1.4. I decided to do a PI test on one of the leads and the one minute and 10 minute were the same at about 14.2 for a PI of 1. I know a PI of one is low and it should be at least 2 or greater.
From this I am going to recommend that the motor is damaged and should not be accepted as is. Do you guys agree with this procedure and recommendation?
Just as a side note, it is very humid out today if that would have any great effect.
I instructed the technicians to then perform a DAR test on the motor. The results for this were as follows:
A = 30 sec =9.1
60 sec 14.2
DAR = 1.56
B= 30 sec = 14.1
60 sec = 16.3
DAR = 1.15
C= 30 sec = 14.0
60sec = 16.2
DAR = 1.15
Only the A phase DAR reading was over 1.4 which appeard to be good but the other two were below 1.4. I decided to do a PI test on one of the leads and the one minute and 10 minute were the same at about 14.2 for a PI of 1. I know a PI of one is low and it should be at least 2 or greater.
From this I am going to recommend that the motor is damaged and should not be accepted as is. Do you guys agree with this procedure and recommendation?
Just as a side note, it is very humid out today if that would have any great effect.