Electrical driver start/stop 1

[roker]

hello,

according to the sequence of operation a pump with a 1HP electrical motor starts every 7 minutes for 2 minutes and stops for another 7 min and so on.
can the electrical motor be started and stopped for such a mode of operation? is there any recommendation for the maximal start/stop per aperiod of time?

regards,
roker

 

[zdas04]

Roker,
You might get a better read on this issue in one of the electrical fora. Either motors or motor controllers. Those guys are a bit strange, but very helpful.

David

 

[electricpete]

I resemble that remark!

http://www.joliet-equipment.com/allowable_starts.htm

You have one start per 9 minutes or 6.7 starts per hour.

It also depends on speed and inertia. Worst case is high speed. Assuming you have 1hp 2-pole motor with low inertia load, you are allowed 15 starts per hour with minimum 75 seconds off between starts. You are well within these limits. If you have 4-pole motor you are allowed even more starts.

If your pump has inertia above NEMA standard the limit would be more restrictive. but I doubt that is the case for your pump load. Even fans (which generally have higher inertia than pumps of comparable speed and horsepowera0 usually are lower than the NEMA standard inertias

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[electricpete]

I forgot to say these are based on NEMA requirements.

Even though you are within the NEMA requirements you might certainly anticipate possible reduced motor life compared to less-frequent start motors. NEMA doesn't address probabilistic things like lifetime.

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[Bjegovic]

you shall be fine with this sequence.

normally, such small motors can be started 10 times per hour or even more, so I agree with electricpete.

if still in doubt, contact the motor manufacturer!