mv jr yasnac/yaskawa spindle motor problem

[dannystooblue]

I am having a problem with the spindle motor or drive. It typically starts forward really slow but will start in reverse most of the time normal. In forward rotation it seems to be under powered, like maybe one of the 3 phases is not getting all the power required. I have an extra drive and spindle motor but don't want to replace both if I don't need to. Any suggestions would be appreciated. Sometimes it works just fine forward and reverse. Sometimes powering off the machine and powering it back on helps. When it orients for a tool change it kind of lugs. At low rpm's it seems to really run un-constant.

Danny

[underthetire]

Could be one of two thing. Bad transistor packs in the drive, or High/Low winding contactor set, Usually labeled KM1, KM101.

[dannystooblue]

Is there a way to test each of these? which would be easier to test first? How would I go about it?


Danny

[underthetire]

SDU is hard to test without prints. The contactor should read close to 0 ohms with a meter and POWER OFF on the machine. You can manually push in the contactor and check the resistance accross the contacts. If they look burnt, they are probably NFG as well. The newer style will be different if you do need to change them. BE VERY CAREFULL to put the new ones in correctly. The A1 and A2 terminals are for the coil. Those tend to be different on the newer ones. Get it wrong and you let the smoke out of other components.