3 phase motor monitoring
3 phase motor monitoring
(OP)
Can a single phase current monitor be used to determine if a 3 phase motor is running? I don't need an analog indication, only running or not running. Under normal conditions, I am confident that the single phase current switch will be fine, but my concern comes if I blow a fuse on one phase. It's an old panel so the motor is fused individually on each leg.
What will happen if I blow one phase? Will the other phases blow from the load change?
What will happen if I blow one phase? Will the other phases blow from the load change?





RE: 3 phase motor monitoring
Normally, motor running is determined by the status of the motor starter contactor. Auxiliary contacts from the contactor indicate if the starter is on or off.
The current monitor would provide a backup to this. If the fuse blows on the phase being monitored and you get indication that motor is off, what is this information used for?
RE: 3 phase motor monitoring
RE: 3 phase motor monitoring
http://www.loadcontrols.com/products/products.html
They have some relative inexpensive power sensing products for motors.
David Baird
Sr Controls Designer
EET degree.
Journeyman Electrician.
RE: 3 phase motor monitoring
But if the panel is so unreliable, maybe efforts should be focused there.
RE: 3 phase motor monitoring
Keith Cress
kcress - http://www.flaminsystems.com
RE: 3 phase motor monitoring
RE: 3 phase motor monitoring
RE: 3 phase motor monitoring
RE: 3 phase motor monitoring
RE: 3 phase motor monitoring
Have you considered a fuse monitor? http
Sorry about the mess the link is in - anyone know how to avoid this problem?
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If we learn from our mistakes I'm getting a great education!
RE: 3 phase motor monitoring
Try WWW.tinyurl.com
ED
RE: 3 phase motor monitoring
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If we learn from our mistakes I'm getting a great education!
RE: 3 phase motor monitoring
Or, use a sail switch as dpc or itsmoked suggested. You can fabricate one from a few square inches of thin metal of a type that will survive your environment and a limit switch. Cheap rugged and dependable.
Bill
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"Why not the best?"
Jimmy Carter
RE: 3 phase motor monitoring
More accurate than that is to use a Power Factor monitor on one phase in the same way. Current fluctuates with voltage, power factor does not.
RE: 3 phase motor monitoring
If you install properly selected motor rated dual rating fuses, these will protect your machine on single phasing by blowing one of the remaining two fuses, since the current in remaining two phases rises to almost twice.
Govind
Electrical Engineer
FFC, Pakistan
RE: 3 phase motor monitoring
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RE: 3 phase motor monitoring
Thank you for participating.
Keith Cress
kcress - http://www.flaminsystems.com
RE: 3 phase motor monitoring
xJAyx what is the motor voltage?
What is the supply voltage?
Are they the same?
Are you trying to determine if the fan motor is running or are you trying to determine if it is single phasing or both?
Tom
None of us is as smart as all of us.
RE: 3 phase motor monitoring
Check out this URL and see if these devices will help solve your phase loss concerns. (Single phasing) They appear to be very economical. h
Tom
None of us is as smart as all of us.
RE: 3 phase motor monitoring
I will try this again here is the URL.
h
Tom
None of us is as smart as all of us.
RE: 3 phase motor monitoring
Just copy and paste the url in the address bar and it will work. I tried it and it is OK I must not have hi-lighted all of it when it was copied.
Tom
None of us is as smart as all of us.
RE: 3 phase motor monitoring
It's a limitation of how the site processes HTML. When it encounters a $ symbol it truncates the address at that point. I'm sure folks can figure it out from what you posted.
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If we learn from our mistakes I'm getting a great education!
RE: 3 phase motor monitoring
Thanks Scotty, I thought that I had goofed.
Tom
None of us is as smart as all of us.