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Author Topic: To switch on or not?  (Read 2031 times)

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To switch on or not?
« on: July 25, 2013, 09:03:16 AM »
I have managed to blow a DG3S 8020 drive with my 75v servo motors and since removing the drive I have just noticed that the resistance from the main PSU (now 48v) to the chassis of the cabinet is reading zero on the ohmmeter. If I disconnect the logic PSU (seperate PC PSU to supply 5v and 12v which is installed in the cabinet) then the resistance is high.
So, is this a faulty PC PSU or am I worrying about nothing?

Offline Hood

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Re: To switch on or not?
« Reply #1 on: July 25, 2013, 09:40:05 AM »
What are you measuring between?

Hood
Re: To switch on or not?
« Reply #2 on: July 25, 2013, 09:45:16 AM »
Between the fuse (between my 48v psu capacitor and servo drive) and the chassis, or star earthing block. This is with the power to everything switched off.

Offline Hood

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Re: To switch on or not?
« Reply #3 on: July 25, 2013, 11:15:47 AM »
Ok but is your main power supply connected to anything else? You said you have removed the drive but is there anything else still connected?
 

Hood
Re: To switch on or not?
« Reply #4 on: July 25, 2013, 11:28:01 AM »
Yes, the 48v power supply is connected to two stepper drives and two servo drives. If the PC PSU is disconnected from the servo drives, then the main 48v power supply has no connection to earth which is why I am thinking it is the PC PSU which is at fault.
The PC PSU powers a BOB with 5v, a couple of 12v fans and provides the 12v to the servo drives. Are there any other measurments I can take to verify the PCPSU is at fault before I strip it out?

Offline Hood

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Re: To switch on or not?
« Reply #5 on: July 25, 2013, 02:12:19 PM »
If you disconnect your logic power supply and meter between the 12v and 0v and 5v and 0v on that supply you should get some resistance, if none then it is certainly sounding like there is an issue with it.
Hood
Re: To switch on or not?
« Reply #6 on: July 29, 2013, 08:26:07 AM »
Hi Hood, there is no resistance between 12v and 0v or 5v and 0v but I bit the bullet and switcher her on.
All seems fine at the monent with the servi drivers working ok. Not sure how this will pan out with noise issues but thanks for your support so far.