Motor high amps
Motor high amps
(OP)
Hi.
In our plant DCS there's always current (amps) icon associated with each motor. What does this current value gives me ?
And, how can i know the max and min amps for any motor ?
Regards,
In our plant DCS there's always current (amps) icon associated with each motor. What does this current value gives me ?
And, how can i know the max and min amps for any motor ?
Regards,





RE: Motor high amps
"Theory is when you know all and nothing works. Practice is when all works and nobody knows why. In this case we have put together theory and practice: nothing works... and nobody knows why! (Albert Einstein)
RE: Motor high amps
RE: Motor high amps
I remember a scheme where the CTs were over or under wound as required so that 150% of motor current corresponded to 5 Amps in the secondary circuit of the CT. The software was then set up so that a 100% on the monitor indicated 150% of rated current. But, what your DCS indicates may depend on the philosophy of the engineer who designed it.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Motor high amps
I mean, if the maximum allowed current is 60 amps, and it showed in the DCS that it is 40 amps, does this indicate a problem in the driven equipment ?
If, yes what is the possible causes for this.
And, vice versa, if the current in the DCS is like 70 amps, what does this indicate ?
RE: Motor high amps
But as David Beach said, we have no idea how the DCS was configured and what current values were programmed into it. The DCS knows nothing about the motors except what someone told it.
"Theory is when you know all and nothing works. Practice is when all works and nobody knows why. In this case we have put together theory and practice: nothing works... and nobody knows why! (Albert Einstein)
RE: Motor high amps
If you exceed that number of amps you are reducing the motor's life by some rate depending on how much you exceed it by.
That said, your DCS system better be accurately showing the current. At some point in time someone should have used a clamp-on ammeter to confirm that the DCS is correctly reporting the current. The DCS should be showing 100% when the MAX current is reached.
Keith Cress
kcress - http://www.flaminsystems.com
RE: Motor high amps
RE: Motor high amps
It is trivial to have crappy, wrong, non-valid numbers showing on a DCS. If you use a separate tool to determine the motor's current then go to the DCS and find they agree then you can start investigating why your motor really is drawing less current than expected.
In some cases a low reading indicates a serious problem in others it means no load. We can't tell you based on the scant information you've coughed up.
Keith Cress
kcress - http://www.flaminsystems.com
RE: Motor high amps
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RE: Motor high amps
RE: Motor high amps
Second, as to minimum amps, the motor completely unloaded will still draw somewhere between 20 and 50% of nameplate FLA. So, I would doubt that displayed minimum amps have anything to do with the motor. Instead, the minimum amps is probably being used to indicate loading conditions in the connected load. To know what the significance of that indication is, you would have to know how the load uses torque and what operational limits to torque exist. It would not be possible to say much more about it from here since we know essentially nothing about the load (except that it is some kind of pump).