Determining if motor is turning or locked in sealed unit 1

[EmergencyPowered]

I was wondering if I can determine if a sealed circulator
pump is rotating or locked up by analyzing voltage and current as in power factor, etc. I have and can use a HIOKI
analyzer, but do not know relation of phase angle to determining each state. Motor uses a capacitor start. Current is flowing, draws a nice arc, but can I prove rotation?

 

[EmergencyPowered]

oh yeah, motor is simple 120v single phase.

 

[dpc]

If motor is not turning it will be drawing locked rotor current which will be several times the normal full load current. All you need to know is the rated current.

Power factor at locked rotor will be extremely low.



David Castor

http://www.cvoes.com

 

[EmergencyPowered]

Thanks, I forgot the obvious here. I'm embarassed....

 

[Skogsgurra]

I ran a test on a small single-phase motor. This one is 90 W at 220 V, 50 Hz. Your motor is probably impedance protected, which makes starting and locked rotor current a lot less compared to running current.

It is also possible that the capacitor makes power factor considerations less reliable when judging run/blocked from the measurements. In this case (90W) the power factor changes very little from locked to running condition.

I think that a simple check with a clamp-on ammeter and comparison to rated current is your best bet. Also, even if these little pumps are rather silent, it will usually be possible to hear if they are working if you use a stethoscope (or wooden stick) to listen to it.

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[waross]

That's nice Gunnar. Thank you.

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

 

[EmergencyPowered]

Thank you gentleman. The circulator is running at .8amps (.72a rating) and is running, but it is one silent little TACO!

 

[rbulsara]

Or more importantly you can check whatever it is circulating (hot water of heating system??) is indeed being circulated.

Rafiq Bulsara

http://www.srengineersct.com