Conduit Banging Noise

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wire4u73

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I am not sure if this is the right forum or not but here is the question. I have a client that has an existing 10HP motor approximately 150' from the electrical panel every time the motor starts up the conduit makes a banging noise. The owner would like to know what is causing this noise and if there is a solution to make it stop. Any suggestions?
 
What size wire is feeding it?
Is the pipe secured?
Is a flexable connection at the motor?
 
What voltage and phase characterisitics. If its a 208 3 P it could be drawing as much as 180 at start. The noise could possibly the conductors slaping in the raceway or maybe the raceway is moving.

Chck the supports
 
Without actually seeing the install or hearing the noise, I would suggest vibration feedback from the motor, inadequate conduit strapping, possibly a current imbalance in the conductors causing some other conductor in the conduit to be slapping the interior surface of the conduit.
 
cpal said:
What voltage and phase characterisitics. If its a 208 3 P it could be drawing as much as 180 at start. The noise could possibly the conductors slaping in the raceway or maybe the raceway is moving.
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I would bet this is the reason and it is not that uncommon.

In my opinion it is not broken but if the owner wants to fix it you could add a soft start to the motor or increase the size of the conductors.
 
cpal said:
What voltage and phase characterisitics. If its a 208 3 P it could be drawing as much as 180 at start. The noise could possibly the conductors slaping in the raceway or maybe the raceway is moving.

Chck the supports
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We have some Cranes that the 480 volt wires that feed them do that occasionally.
 
cpal said:
The noise could possibly the conductors slaping in the raceway
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ptonsparky said:
conductors moving around in the conduit. Common enough.
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There are a few things about my work I love. When I get to turn the new lights on in a big structure, the sound and feel around big gennys, the sound of a big tranny energizing, and of course, the sound described above.
 
Thanks for all your help. I am going to send a technician out to the site to do further investigation. These are some of the same ideas that I had want some more expert opinions.
 
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