4 hour run in for commissioning?

[gronk2003]

We are presently in thew middle of a big expansion and the question has come up about a recommendation not do a 4 hour run in on our motors. Any thoughts on this?

 

[electricpete]

I would say minimum 1 hour run. 2-4 gives even better confidence and may be more appropriate for larger motors which take longer to reach thermal equilibrium. Make sure you measure parameters at the end of the run: temperatures, vibration, and current.

I personally have been bit twice this year by motors that didn’t show a problem when monitored during first few minutes after repair. We either didn’t leave it running long enough or measured at beginning of the run but not at the end of a run.

 

[jbartos]

Suggestion: The longer run may be required if the following exist:
1. Nature of the motor load
2. Motor size
3. High ambient temperature
4. High humidity
5. Low quality power supply
6. Higher vibration
7. Etc.

 

[pennpoint]

gronk2003
Well "gronk" its your motors, your installation, your customer with your name all over them! How much time are you willing to prove your metal? How confident are you.
As (jbartos) points out how many of those items he listed and how correctly did you address them there may be more. Any one of them can cause you and your customer problems down the road.
What are your $/hr cost?
Find a problem now or later.
Your at that juncture now. Its time to cut bait or fish.
If you worked for me, I'd tell you to decide "its your project. But do not make my company look bad".

Good Luck,
more to follow I am sure

pennpoint

 

[Midos]

4 hour load runs are the norm during commissioning in the uk and offshore etc. However we only do a 30 minute no load run while checking the NDE & DE temperature and for exessive vibration.

 

[jbartos]

Suggestion: If any monitored parameter is increasing/decreasing, judging the parameter adversity, during the commissioning period, then it is necessary either to stop the commissioning or prolong the test to find out the parameter increases/decreases after 4 hours.