Will clamp-on meters on DC drives output work accurately ?

[edison123]

How accurate are clamp-on meters while measuring output currents of DC drives?

We are having an instance of DC drive panel meter showing a current of 50 amps while two clamp-on (hall effect) meters showing 70 amps.

Will the old fashioned way of using a shunt on the output terminal will help?

Muthu

http://www.edison.co.in

 

[davidbeach]

No idea. But could it be that one is reading max and the other is reading average?

 

[waross]

Or one is reading average and one is reading RMS. On AC systems I have seen noticeable indication errors due to an average reading meter and a distorted sine wave that did not have the same form factor (ratio of average to RMS) as a true sine wave.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[edison123]

David, Bill - This is about DC drives.

Muthu

http://www.edison.co.in

 

[waross]

I was thinking a PWM type of drive rather than a smooth variable DC voltage such as from an MG set.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[davidbeach]

I was also thinking PWM. How is the DC being regulated?

 

[catserveng]

If it is a PWM drive, maybe this will be helpful,

http://www.tek.com/dl/55W_28942_0_HR_Letter.pdf

or this,

https://www.ab.com/support/abdrives/documentation/fb/1020.pdf

MikeL.

 

[edison123]

The client swapped the ABB Drive to Siemens Drive and problem was solved and the motor is running well now.

Thanks guys for your inputs.

I will try to get and post both the drive details.

Muthu

http://www.edison.co.in