TRUE motor running indication with current monitor
TRUE motor running indication with current monitor
(OP)
How could I get a "true" motor running indication? I was using the motor starter N.O. contacts but since my control circuit is 24VDC and my motors are running at460VAC so it is not a "true" motor running indication when 460VAC is down. My client also asked a current indication for the motor on the door.
Where can I get a device which can show the running current on the door but also has a dry contact output to indicate if there is any current has been detected? I don't want this device to have any over-current or under-current or any sort fo protection. Just a simply current amps indication and a relay output or dry contact output to show motor is running or not running.
Where can I get a device which can show the running current on the door but also has a dry contact output to indicate if there is any current has been detected? I don't want this device to have any over-current or under-current or any sort fo protection. Just a simply current amps indication and a relay output or dry contact output to show motor is running or not running.





RE: TRUE motor running indication with current monitor
RE: TRUE motor running indication with current monitor
RE: TRUE motor running indication with current monitor
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RE: TRUE motor running indication with current monitor
RE: TRUE motor running indication with current monitor
Keith Cress
kcress - http://www.flaminsystems.com
RE: TRUE motor running indication with current monitor
RE: TRUE motor running indication with current monitor
I can imagine a lot of cases where doing something when somethings has to be turning and it's not could lead to very bad things.
Keith Cress
kcress - http://www.flaminsystems.com
RE: TRUE motor running indication with current monitor
http://www.time-mark.com/Default.aspx
Mike L.
RE: TRUE motor running indication with current monitor
I saw nothing there that would work.
Keith Cress
kcress - http://www.flaminsystems.com
RE: TRUE motor running indication with current monitor
Of course I've also used an SEL motor protection relay, and more recently an SEL 751A relay to provide a similar indication as the OP is looking for, just depends on how big the motor is, how important the process and how much money they are willing to spend.
Mike L.
RE: TRUE motor running indication with current monitor
Motor running starts the timer
reset the timer with the prox or encoder
alarm and stop the motor output contactor or vfd if the timer times out.
RE: TRUE motor running indication with current monitor
A.
RE: TRUE motor running indication with current monitor
Are you here or are we wasting our time?
Keith Cress
kcress - http://www.flaminsystems.com
RE: TRUE motor running indication with current monitor
classIdiv2 (if you are still with us)
Here is an example of a motor protection relay that will give you load monitoring indication that your motor is actually turning, without an external sensor.
The key difference that would make this more reliable is below:
I would program it so that after XX seconds, if the kW is not at least 20% of the motor rating and the PF is not at least .3, then you can know that the motor is NOT rotating. This works better than just monitoring current, because current will fluctuate with voltage regardless of load. kW will not, kW is always load. Adding in the PF monitoring isn't absolutely necessary, but it's there and it would function as a double-check. This would replace your Over Load Relay and on this unit, the display can be mounted on the door. There are several others on the market just like this; Load Monitors Corp has one, Siemens has one, and there is another one from Canada that I can't remember the name of and I'm sure several others. The key is, look for one that is a kW monitor
I would not use that from a personnel safety standpoint however, there are other more specific rotation monitors for that which will require an external sensor. But from a machine or process standpoint, this works great.
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